Protein Requirement Calculator: g per Day by Clinical Condition

Grams of protein a day from the published g/kg/day range for a clinical condition, on a weight basis you choose and declare. Prints the bottom of the range, the top, the midpoint and the nitrogen each works out to — because the literature states a range and a page that prints one number hides that. The restricted renal targets and the raised renal-replacement targets are separate, labelled rows.

Last updated 1 Oct 2026

These figures come from published predictive equations and reference ranges. They are not a measurement of the person in front of you, and they are not a feeding prescription — they are a starting estimate for a dietitian or clinician to weigh against the patient, the local policy and, where it is available, measurement.

Protein from a published g/kg/day range

condition and weight → g protein/day across the range, plus g nitrogen/day

Clinical condition — which published range to applyEach row is a numeric range taken from the published literature, not a recommendation this page is making. The table further down the page names the source behind every row and the body weight basis that source used. Read it before trusting a row: the two renal families point in OPPOSITE directions, and the critical-illness rows with a BMI in their label are stated by their source against IDEAL body weight, not actual.

Weight to calculate on (kg)The weight you have decided to use, in kilograms. This page does not choose it for you and does not work it out: if you want ideal or adjusted body weight, get the number from the ideal body weight page or the adjusted body weight page and type the answer here. Which weight to use at all is argued out on the dosing weight selection page.

What that weight isA declaration, not a calculation: it changes no arithmetic, and the page uses whatever number you typed above. It is here because the answer is meaningless without it, and because the page can then tell you when the row you picked was published against a different basis. In obesity the choice moves the answer by tens of grams a day, and that is the commonest protein error in practice.

Actual body weight (kg) — only for the comparison rowOptional. Leave at 0 to hide the comparison. If you are calculating on an ideal or adjusted weight, put the measured weight here as well and the page prints the calculation weight as a percentage of it — so you can see at a glance how large the adjustment you have made actually is.

Total energy target (kcal/day) — optionalOptional. Leave at 0 to hide the percentage-of-energy rows. Get the figure from the energy requirement page if you need one. If you give a daily energy figure, the page works out what fraction of it the protein would be, counting protein at 4 kcal/g. That is the figure to compare against the 10 to 35 per cent of energy the US Dietary Reference Intakes allow for adults.

Custom range — low end (g/kg/day)Only used when the condition selector is set to “Custom range”. Locked otherwise, so the numbers you can see are always the numbers the page used. If you enter the two ends the wrong way round the page sorts them for you and says so.

Custom range — high end (g/kg/day)The other end of your own range. Use this for a local guideline, or for a published range this page does not carry. The arithmetic is identical; only the provenance changes, and the provenance then belongs to you rather than to this page.

87.5g protein/dayExample

a 70 kg ward inpatient with an acute illness, on the 1.0 to 1.5 g/kg/day range, weight declared as actual

Protein from a g/kg/day range, and the nitrogen it carries

g protein/day = (g/kg/day) × W · midpoint = (low + high)/2 × W · g N/day = (g protein/day) / 6.25 · protein energy = (g protein/day) × 4 kcal/g · % of energy = 400 × (g protein/day) / (kcal/day)

W: the weight you typed, in kg. This page never computes it. Actual, ideal and adjusted body weight all belong to the medical pages linked above, and which of them to use belongs to the clinician
low, high: the two ends of the published g/kg/day range for the row selected. The table below names the source of each pair. Where a source states a single figure rather than a range, the two ends are equal and the page says so by printing a range width of zero
6.25: the conventional nitrogen-to-protein factor, from the observation that protein averages about 16 per cent nitrogen (1/0.16 = 6.25). It is a convention, not a constant: measured nitrogen content across proteins runs from about 13 to 19 per cent, which would give factors from 5.26 to 7.69. Every page in this group uses 6.25, and so does the medical nitrogen balance page, so the arithmetic is consistent across them
4 kcal/g: the Atwater factor for protein, used only for the percentage-of-energy rows. Intravenous amino acids are assigned the same 4 kcal/g on the parenteral page

Worked example

a 70 kg ward inpatient with an acute illness, on the 1.0 to 1.5 g/kg/day range, weight declared as actual
The row gives a range, so work both ends. Bottom: 1.0 × 70 = 70 g protein a day. Top: 1.5 × 70 = 105 g. The range is 35 g of protein a day wide, which is half as much again as the bottom of it — that width is the honest answer and it is why this page refuses to print one number on its own.
The midpoint, which is the headline: (70 + 105)/2 = 87.5 g protein a day. It has no special status. It is the middle of a published spread, nothing more, and where in that spread a given patient should sit is a clinical judgement about catabolism, absorption and monitoring.
Nitrogen, which is the currency the parenteral and nitrogen-balance pages work in: 87.5 / 6.25 = 14.0 g N a day, with the range running 70/6.25 = 11.2 g N to 105/6.25 = 16.8 g N.
Energy, if you want the percentage: 87.5 × 4 = 350 kcal a day of protein energy. Against a 2,000 kcal target that is 17.5 per cent, comfortably inside the 10 to 35 per cent the Dietary Reference Intakes allow for adults.
NOW CHANGE ONLY THE WEIGHT BASIS AND WATCH THE ANSWER MOVE. Take a patient measuring 120 kg whose ideal body weight is 70 kg, in critical illness at a BMI over 40. The published row is 2.0 to 2.5 g/kg of IDEAL body weight: 140 to 175 g a day, midpoint 157.5 g. Apply the same row to the actual 120 kg and you get 240 to 300 g a day, midpoint 270 g — a figure no guideline anywhere recommends, arrived at by reading one word of the row wrongly. That is the whole reason the weight basis is a declared field on this page and why the page says something when the declaration and the row disagree.
And the renal direction, which is the other way the answer goes badly wrong. The same 70 kg patient conservatively managed on CKD stage 4 without diabetes: 0.55 to 0.60 g/kg/day, so 38.5 to 42 g a day, midpoint 40.25 g. Put the same patient on continuous renal replacement therapy and the row becomes 1.5 to 1.7 g/kg/day, so 105 to 119 g a day, midpoint 112 g — nearly three times as much. The two rows are adjacent in the selector and point in opposite directions; the labels say NOT on dialysis and ON renal replacement therapy in capitals for that reason.
Carry the nitrogen figure to the parenteral macronutrient page when the route is intravenous, or to the enteral feed rate page to see what volume of a given feed would deliver it. Measured nitrogen balance, which is a different question from a target, is on the medical nitrogen balance page.

Where each row’s numbers come from

Numbers, sources and the weight each source attaches its number to. The numbers are facts and are restated across many independent publications; what is NOT reproduced here is any guideline’s recommendation text, its criteria or its own table layout, because those are the expression of the guideline and belong to the body that wrote it. Where restatements of one guideline disagree about the weight basis — which is genuinely the case for the renal rows — this table says so rather than picking one. Two rows are published against IDEAL body weight and are the commonest place this arithmetic goes wrong.
Row	g/kg/day	Source of the figures	Weight basis the source states
Healthy adult, maintenance	0.66 to 0.80	US Institute of Medicine Dietary Reference Intakes: EAR 0.66, RDA 0.80	Body weight, healthy adults
Healthy adult 65 or over	1.0 to 1.2	ESPEN Expert Group (Deutz 2014) and the PROT-AGE group (Bauer 2013)	Body weight
Ward inpatient, acute illness or polymorbid	1.0 to 1.5	ESPEN polymorbid inpatient guidance states a minimum of 1.0; the PENG requirements group states 1.0 to 1.5	Actual body weight
Older adult with acute or chronic illness	1.2 to 1.5	PROT-AGE and ESPEN Expert Group; up to 2.0 is quoted for severe illness	Body weight
Critical illness, BMI under 30	1.2 to 2.0	ASPEN and SCCM critical care guideline	ACTUAL body weight
Critical illness, BMI 30 to 40	at least 2.0	ASPEN and SCCM critical care guideline	IDEAL body weight
Critical illness, BMI 40 or over	up to 2.5	ASPEN and SCCM critical care guideline	IDEAL body weight
Major burns	1.5 to 2.0	ESPEN burns recommendations and ISBI practice guidelines	Body weight
Pressure ulcer or wound healing	1.25 to 1.5	EPUAP and NPUAP pressure ulcer nutrition guidance	Body weight
Cirrhosis or chronic liver disease	1.2 to 1.5	ESPEN liver disease guidance	Body weight; dry weight where there is ascites
Cancer	1.0 to 1.5	ESPEN oncology guideline: above 1.0, up to 1.5 if possible	Body weight
CKD 3 to 5, conservative, no diabetes	0.55 to 0.60	KDOQI 2020 nutrition in CKD	Restatements differ — confirm against your own copy
CKD 3 to 5, conservative, with diabetes	0.60 to 0.80	KDOQI 2020 nutrition in CKD	Restatements differ — confirm against your own copy
CKD 3 to 5, very-low-protein with keto-analogues	0.28 to 0.43	KDOQI 2020 nutrition in CKD, specialist supervision	As above
Maintenance dialysis	1.0 to 1.2	KDOQI 2020 nutrition in CKD	Restatements differ — confirm against your own copy
AKI, not on RRT, non-catabolic	0.8 to 1.0	KDIGO acute kidney injury guideline	Body weight
AKI on renal replacement therapy	1.0 to 1.5	KDIGO acute kidney injury guideline	Body weight
Continuous RRT, or hypercatabolic on RRT	1.5 to 1.7	KDIGO acute kidney injury guideline: up to a maximum of 1.7	Body weight

The same 70 kg patient across five rows

One weight, five rows, a factor of four and a half from top to bottom. The point of the table is that the condition selector, not the weight, is doing almost all of the work on this page — so a row chosen carelessly is a much larger error than a weight estimated roughly. Read the labels: the first two rows are deliberate restrictions and the last is a deliberate elevation, and the conservatively managed kidney and the kidney on a filter are not the same patient.
Row	Bottom (g/day)	Midpoint (g/day)	Top (g/day)	Nitrogen at midpoint (g N/day)
CKD 3 to 5, very-low-protein with keto-analogues	19.6	24.9	30.1	3.98
CKD 3 to 5, conservative, no diabetes	38.5	40.3	42.0	6.44
Healthy adult, maintenance	46.2	51.1	56.0	8.18
Ward inpatient, acute illness	70.0	87.5	105.0	14.00
Continuous RRT, or hypercatabolic on RRT	105.0	112.0	119.0	17.92

Why this page prints a range, a weight basis and a source rather than a requirement

A protein requirement is not a measurement. There is no instrument that reads it off a patient, and nothing upstream of this page prescribes it the way a prescription prescribes an infusion rate. What exists is a body of published g/kg/day ranges, attached to clinical conditions, each with a provenance and each disagreeing with its neighbours by a clinically meaningful margin. This page multiplies one of those ranges by a weight you supply. That is the whole of what it does, and saying so plainly is the only honest framing: the number is what the published range gives for these inputs, and the decision about what to actually give belongs to the dietitian or clinician who owns it.

Which is why there is no single number at the top. The headline is the midpoint of a range and the two ends are printed immediately below it, because a reader shown only a midpoint does not know whether the published spread around it was 5 per cent or 60 per cent wide. For a ward inpatient the range is 1.0 to 1.5 g/kg/day — the top is half as much again as the bottom. For critical illness below a BMI of 30 it is 1.2 to 2.0, and at 80 kg that is the difference between 96 and 160 g of protein a day. Printing the midpoint alone would make that spread invisible, and the spread is the most important thing on the page.

The weight basis is a declared field because it is the commonest error in practice. Two of the rows here — critical illness at a BMI of 30 or more — are published by their source against IDEAL body weight, and applying them to a measured weight produces an intake nobody has ever recommended. At 2.0 g/kg the gap between an actual 120 kg and an ideal 70 kg is 100 g of protein a day. This page therefore asks you to say which weight you have typed, says something when your declaration and your chosen row disagree, and refuses to compute ideal or adjusted weight itself: those calculations already exist on the medical side and duplicating them would eventually mean two pages on this site disagreeing about the same arithmetic. If you give the measured weight as well, the page prints the calculation weight as a percentage of it, so a large adjustment cannot be made by accident.

The renal rows are the ones worth reading slowly. Protein targets in kidney disease point in two opposite directions depending on one fact: whether the patient is being managed conservatively or is on renal replacement therapy. Conservative management of CKD stages 3 to 5 restricts protein — 0.55 to 0.60 g/kg/day without diabetes — in order to slow progression and limit nitrogenous waste. A patient on dialysis or on a continuous filter loses amino acids into the circuit and is frequently catabolic, and the target rises: 1.0 to 1.2 g/kg/day on maintenance dialysis, 1.0 to 1.5 in acute kidney injury on renal replacement therapy, and up to 1.7 on continuous renal replacement therapy or when hypercatabolic. For a 70 kg patient the restricted row gives about 40 g a day and the continuous-filter row about 112 g. Getting those the wrong way round is not a rounding error, so every renal row on this page says NOT on dialysis or ON renal replacement therapy in capital letters, and the rows are deliberately not adjacent shorthand labels that could be misread at a glance.

What the page deliberately does not do. It does not decide where in a range a patient sits. It does not reproduce any guideline’s recommendation text, criteria list or table, because the numbers are facts and widely restated while the text is the guideline’s own work — the table above gives numbers and names sources rather than quoting them. It has no view on whether a high target is wise: in critical illness the EFFORT Protein trial randomised 2.2 g/kg/day or more against 1.2 g/kg/day or less and found no overall benefit, with slower discharge and higher 60-day mortality among patients with acute kidney injury, and a page that printed a large number without saying so would be misleading by omission. And it will not answer at all on a weight of zero. For the nitrogen you would actually be delivering by a given route, use the enteral feed rate page or the parenteral macronutrient page, both of which use the same 6.25 factor. For measured nitrogen balance from a urine collection — a different question, answered from a lab result rather than from a target — use the medical nitrogen balance page. Refeeding risk, which is what governs how fast any of this can be introduced, is assessed on the refeeding syndrome risk interpreter.

Frequently asked questions

Why does the page not just tell me the protein requirement?

Because nothing published supports a single number, and a page that printed one would be inventing precision. The literature gives ranges, the ranges differ between bodies, and the choice of where to sit inside a range depends on catabolic state, on what is being absorbed and on monitoring that a calculator cannot see. So the page prints the range, names the source, shows the nitrogen each end carries and leaves the decision with the person who can see the patient. The midpoint at the top is a convenience, not a recommendation.

Should I use actual, ideal or adjusted body weight?

That depends on the row and on the patient, and this page does not decide it. What it does is make the choice visible: you declare which weight you typed, and if the row you selected was published against a different basis the page says so. Two rows here — critical illness at a BMI of 30 or more — are stated by their source against ideal body weight specifically. The argument about which weight to use for what is set out on the medical dosing weight selection page, and the ideal and adjusted weights themselves are calculated on their own pages, linked above. Nothing is gained by this page having a fourth opinion.

Why is 6.25 used to convert protein to nitrogen, and is it exact?

It is a convention, not a constant. It comes from the observation that protein averages about 16 per cent nitrogen, and 1 divided by 0.16 is 6.25. Measured nitrogen content across real proteins runs from roughly 13 to 19 per cent, which would give factors from 5.26 to 7.69, and food-specific factors in the 5.18 to 6.38 range have been published. In clinical nutrition 6.25 is used anyway, because the precision gained by a specific factor is far smaller than the uncertainty in the target itself. Every page in this group uses 6.25, and so does the medical nitrogen balance page, so figures carry across without a hidden conversion.

The conservative CKD row and the renal replacement row are completely different. Is that right?

Yes, and it is the most important thing on the page. Conservatively managed chronic kidney disease restricts protein to slow progression and limit nitrogenous waste: 0.55 to 0.60 g/kg/day without diabetes. A patient on dialysis or a continuous filter loses amino acids into the circuit and is often catabolic, so the target goes up: 1.0 to 1.2 on maintenance dialysis, up to 1.7 on continuous renal replacement therapy. For a 70 kg patient that is roughly 40 g a day against roughly 112 g. The rows are labelled NOT on dialysis and ON renal replacement therapy in capitals because reading them the wrong way round would be a genuinely harmful error in either direction.

What does the very-low-protein row mean, and should I use it?

Almost certainly not unless you are already part of the team doing it. A very-low-protein diet of 0.28 to 0.43 g/kg/day is only safe with keto-analogue or essential amino acid supplementation and renal dietetic supervision, with nutritional status monitored throughout. Without the supplementation the same number is simply undernutrition. The row exists so the arithmetic is available where it is being done deliberately, and the page says so every time it is selected.

Why does the critical illness row show two different figures?

Because two bodies published different answers and hiding one of them would misinform you. The ASPEN and SCCM critical care guideline gives 1.2 to 2.0 g/kg of actual body weight a day. The ESPEN intensive care guideline instead names a single target of 1.3 g/kg/day, delivered progressively rather than from day one. At 80 kg that is 104 g against a range topping out at 160 g. The page prints the ASPEN range as the headline and the ESPEN figure as its own row, and the band note points at the EFFORT Protein trial, which tested a high target against a usual one and did not find the high target better.

Can I use this for a child?

No. Every range on this page is an adult range, and paediatric protein requirements are stated per kilogram by age band on a quite different basis. Nothing here should be applied to a child, and the page carries no paediatric row rather than carrying one that would be wrong. Paediatric maintenance fluid, which is the adjacent paediatric arithmetic this site does cover, is on the medical paediatric maintenance fluid page.

Why does it ask for an energy target, and what is the percentage for?

It is optional and it is a sanity check. Protein counted at 4 kcal/g as a fraction of the total energy you are planning tells you whether the two numbers are coherent: the US Dietary Reference Intakes allow 10 to 35 per cent of energy from protein in adults. A figure above 35 per cent can be a real feature of a high-protein, energy-restricted plan, or it can mean the energy target is too low — the page flags it and takes no view on which. Leave the field at 0 to hide those rows.

Related calculators

References

Institute of Medicine (US), Dietary Reference Intakes for Energy, Carbohydrate, Fibre, Fat, Fatty Acids, Cholesterol, Protein and Amino Acids (National Academies Press, 2005), doi:10.17226/10490. Source for the healthy-adult row: EAR 0.66 and RDA 0.80 g good-quality protein/kg/day, and for the acceptable macronutrient distribution range used in the percentage-of-energy flag. The 35 per cent upper bound was cross-checked against the Australian and New Zealand NHMRC nutrient reference values, which restate the IOM figure as 20 to 35 per cent of energy from fat and an upper limit of 35 per cent of energy from protein while themselves recommending 15 to 25 per cent.
N.E.P. Deutz, J.M. Bauer, R. Barazzoni et al., “Protein intake and exercise for optimal muscle function with aging: recommendations from the ESPEN Expert Group”, Clinical Nutrition 33 (2014), doi:10.1016/j.clnu.2014.04.007, together with J.M. Bauer et al. for the PROT-AGE Study Group (2013). Source for the older-adult rows: 1.0 to 1.2 g/kg/day in health, 1.2 to 1.5 g/kg/day with acute or chronic illness, and up to 2.0 g/kg/day quoted in severe illness or injury.
Guidelines and Audit Implementation Network / ASPEN and SCCM, Guidelines for the Provision and Assessment of Nutrition Support Therapy in the Adult Critically Ill Patient (2016), as restated in independently published guideline summaries. Source for the critical illness rows: 1.2 to 2.0 g/kg actual body weight/day below a BMI of 30, at least 2.0 g/kg IDEAL body weight/day at BMI 30 to 40, and up to 2.5 g/kg IDEAL body weight/day at BMI 40 or over. Only the figures and the weight basis are taken; no recommendation text or table is reproduced.
P. Singer et al., ESPEN guideline on clinical nutrition in the intensive care unit (2019), as restated in independently published implementation summaries. Source for the comparison row: a progressive target of 1.3 g/kg/day, with the same targets calculated on adjusted body weight above a BMI of 30. Carried on the page specifically to show that this and the ASPEN range disagree.
D.K. Heyland et al., the EFFORT Protein trial, and the subsequent secondary analyses published in Critical Care (2023). High protein of 2.2 g/kg/day or more against usual protein of 1.2 g/kg/day or less in critically ill patients at high nutritional risk: no overall benefit, and in the 312 patients with acute kidney injury a slower time to discharge alive (hazard ratio 0.5, 95% CI 0.4 to 0.8) and higher 60-day mortality (relative risk 1.4, 95% CI 1.1 to 1.8). Cited because the top of the critical-illness range on this page is not a target the evidence supports chasing.
KDOQI Clinical Practice Guideline for Nutrition in CKD, 2020 update (National Kidney Foundation / Academy of Nutrition and Dietetics), as restated in independent peer-reviewed reviews of low-protein diets in CKD. Source for the renal rows: 0.55 to 0.60 g/kg/day in metabolically stable CKD stages 3 to 5 without diabetes, 0.60 to 0.80 g/kg/day with diabetes, 0.28 to 0.43 g/kg/day as a very-low-protein diet with keto-analogues, and 1.0 to 1.2 g/kg/day on maintenance dialysis. Restatements of this guideline differ about whether the weight is actual, ideal or adjusted, which is why the table above says so instead of choosing.
KDIGO Clinical Practice Guideline for Acute Kidney Injury (2012), recommendation 3.3.4. Source for the AKI rows: 0.8 to 1.0 g/kg/day in non-catabolic AKI without dialysis, 1.0 to 1.5 g/kg/day in AKI on renal replacement therapy, and up to a maximum of 1.7 g/kg/day in patients on continuous renal replacement therapy and in hypercatabolic patients.
Food and Agriculture Organization of the United Nations, Food energy — methods of analysis and conversion factors (FAO Food and Nutrition Paper 77, 2003), chapters 2 and 3. Source for the nitrogen-to-protein factor and its limits: protein averages about 16 per cent nitrogen, giving 1/0.16 = 6.25, while measured nitrogen content runs from about 13 to 19 per cent (factors 5.26 to 7.69) and Jones factors for commonly eaten foods run from 5.18 to 6.38. Also the source for the 4 kcal/g protein energy factor used in the percentage-of-energy rows.
Parenteral and Enteral Nutrition Group of the British Dietetic Association, A Pocket Guide to Clinical Nutrition, 5th edition (2018), protein and fluid section, consulted via the publicly distributed summary. Used as a secondary cross-check that the ranges above are the ones UK dietetic practice works from, and as the source for the 1.0 to 1.5 g/kg actual body weight/day general inpatient figure attributed to its own requirements group, the burns figure of 1.5 to 2.0 g/kg/day attributed to ESPEN and the ISBI practice guidelines, the pressure ulcer figure of 1.25 to 1.5 g/kg/day attributed to EPUAP and NPUAP, the cirrhosis figure of 1.2 to 1.5 g/kg/day and the oncology figure of above 1.0 up to 1.5 g/kg/day attributed to ESPEN. Its own table is not reproduced; the figures are cross-cited to the bodies it names. It is also the source for the statement that 6.25 is “just an approximation to give a starting point”.
Derivation performed for this page rather than taken from a source: the width of a published range in g/day is (high − low) × W, so it scales with weight exactly as the target does, and the ratio of the top of a range to the bottom is a property of the row alone. For the ward inpatient row that ratio is 1.5, for critical illness below a BMI of 30 it is 1.67, and for the healthy adult row it is 1.21. A page printing only a midpoint would conceal a 67 per cent spread, which is why this one does not.

CalcEngines health calculators are for education and for checking arithmetic that has already been decided elsewhere. They are not medical advice, they do not decide what to give, and they do not replace the judgement of a doctor, nurse, midwife or dietitian who knows the person in front of them. Every figure depends on the values you enter and on the assumptions stated on the page — check it against the prescription, the product label and your local policy before acting on it.