Parenteral Nutrition Macronutrient Calculator
Parenteral Nutrition Macronutrient Calculator
Energy from the grams in the bag, with the right densities — dextrose monohydrate at 3.4 kcal/g, not 4 — plus the glucose infusion rate and lipid dose against their published ceilings, and both calorie conventions side by side.
Parenteral nutrition energy and substrate load
Grams in the bag to kcal/day250 g dextrose, 90 g amino acids, 250 mL of 20% lipid, 70 kg, total-energy convention
Energy densities, and what they are read against
Amino acid energy = grams × 4 kcal/g
Lipid energy = mL × 1.1 (10%), 2.0 (20%) or 3.0 (30%) kcal/mL
Non-protein energy = dextrose + lipid · Total energy = non-protein + amino acids
Glucose infusion rate (mg/kg/min) = grams of dextrose × 1000 ÷ (weight × 1440)
- 3.4, not 4
- parenteral dextrose is the monohydrate, which carries a water molecule and yields 3.4 kcal/g rather than the 4 kcal/g of anhydrous glucose. Using 4 inflates a 250 g bag by 150 kcal/day. Straight off the package insert: “3.4 kcal/g of dextrose, hydrous”, with 50% dextrose providing 170 kcal per 100 mL
- lipid: about 10 kcal/g, and per mL not proportional
- a lipid emulsion is not pure oil — the glycerol and egg-yolk phospholipid are metabolised too, so a gram of emulsion lipid is about 10 kcal rather than 9. And because phospholipid and glycerin sit at the same absolute concentration in the 10% and 20% products, energy per mL does not scale with strength: 1.1, 2.0 and 3.0 kcal/mL
- amino acids at 4 kcal/g, and whether to count them
- 4 kcal/g is the convention; whether those calories belong in the energy total is genuinely unresolved, and both practices exist. The choice moves the default bag from 1,710 to 1,350 kcal/day. This page computes both and asks which one you mean
- the substrate ceilings, and what this does not compute
- glucose, not exceeding 5 mg/kg/min (ESPEN) against 4 to 5 g/kg/day of utilisation, 2.8 to 3.5 mg/kg/min (German guideline); lipid, 1.5 g/kg/day (ESPEN), 0.7 to 1.3 (German guideline) and “not to exceed 2.5 g/kg/day” (Intralipid label), with a rate limit of 0.11 g/kg/hour. Not computed here: osmolarity, electrolytes, vitamins, fluid volume and calcium-phosphate compatibility — for a made-up solution see the solution osmolarity calculator
Worked example
250 g dextrose, 90 g amino acids, 250 mL of 20% lipid, 70 kg, total-energy convention
Dextrose: 250 × 3.4 = 850 kcal/day. Lipid: 250 mL × 2.0 kcal/mL = 500. Non-protein energy = 1,350 kcal/day
Amino acids: 90 × 4 = 360. Total energy = 1,350 + 360 = 1,710 kcal/day
The convention is worth 360 kcal/day — 21.1% of the total. The same bag is "1,710 kcal" or "1,350 kcal" depending only on which convention is in use
Had dextrose been costed at 4 kcal/g the total would read 1,860 — 150 kcal/day too high, and the commonest arithmetic error in this area
Glucose infusion rate: 250 × 1000 ÷ (70 × 1440) = 2.48 mg/kg/min, below ESPEN's 5 and below the German guideline's 2.8 to 3.5
Lipid dose: 250 × 0.2 ÷ 70 = 0.71 g/kg/day, inside ESPEN's 1.5 and the German guideline's 0.7 to 1.3; lipid is 37.0% of non-protein energy, inside its 25 to 40%
Per kg: 24.4 kcal/kg/day total, or 19.3 non-protein. Which of those to compare against a 20–25 or 25–30 kcal/kg target is exactly the question the convention decides
Energy densities, with the source each comes from
| Component | Energy | Source |
|---|---|---|
| Dextrose monohydrate (hydrous) | 3.4 kcal/g | Dextrose Injection USP prescribing information: “3.4 kcal/g of dextrose, hydrous”. 50% provides 170 kcal/100 mL at 2,523 mOsmol/L; 70% provides 238 kcal/100 mL at 3,532 mOsmol/L |
| Amino acids | 4 kcal/g | Saudi MOH adult parenteral nutrition guideline: “each gram of AA contains approximately 4 kcals” |
| Lipid, per gram of emulsion lipid | about 10 kcal/g | Saudi MOH guideline: “approximately 10 kcal” — above the 9 kcal/g of pure triglyceride, because the glycerol and phospholipid are metabolised too |
| 10% lipid emulsion | 1.1 kcal/mL | Intralipid prescribing information, 2025: “1.1 kcal per mL”; 1.2% egg yolk phospholipids and 2.25% glycerin; osmolality about 300 mOsmol/kg |
| 20% lipid emulsion | 2.0 kcal/mL | Same label: “2,000 kcal/L”; same phospholipid and glycerin; osmolality about 350 mOsmol/kg |
| 30% lipid emulsion | 3.0 kcal/mL | Intralipid 30% label: “3.0 kcal per mL”, 1.7% glycerin; supplied for dilution to 20% or less |
Published substrate ceilings, and where they disagree
| Figure | Guideline or label | At 70 kg |
|---|---|---|
| Glucose not to exceed 5 mg/kg/min | ESPEN intensive care 2019, rec. 23 | 504 g of dextrose a day |
| Glucose utilisation about 4–5 g/kg/day; 3.0–3.5 preferable; 1–2 initially in high-risk patients | German parenteral nutrition guideline, carbohydrates | 280–350 g/day, i.e. 2.8–3.5 mg/kg/min — below ESPEN’s ceiling; 70–140 g/day initially |
| Lipid not to exceed 1.5 g/kg/day | ESPEN intensive care 2019, rec. 25 | 105 g/day, i.e. 525 mL of 20% |
| Lipid 0.7–1.3 g/kg/day, up to 1.5 if energy needs are high; 25–40% of non-protein energy | German parenteral nutrition guideline, lipids | 49–91 g/day, i.e. 245–455 mL of 20% |
| Adult dose not to exceed 2.5 g/kg/day; maximum lipid infusion 0.11 g/kg/hour | Intralipid prescribing information; Saudi MOH guideline | 175 g/day, well above both guideline ceilings; 7.7 g/hour |
| Peripheral formulations 750 to below 900 mOsm/L | Saudi MOH guideline | A route limit, not a substrate limit |
Four numbers that decide whether the bag adds up
A parenteral nutrition prescription is a set of grams and millilitres, and turning those into an energy figure has exactly four places to go wrong. The first is the dextrose density. Parenteral dextrose is the monohydrate and yields 3.4 kcal/g, not the 4 kcal/g of anhydrous glucose; the package insert for Dextrose Injection USP says so in those words, and its 170 kcal per 100 mL of 50% dextrose is the same number restated. Using 4 overstates a 250 g bag by 150 kcal/day, every day, and nothing in the prescription looks wrong.
The second is lipid, where two traps sit together. An emulsion is not pure oil: the glycerol and egg-yolk phospholipid are metabolised too, so a gram of emulsion lipid is about 10 kcal rather than 9. And because phospholipid and glycerin are present at the same absolute concentration in the 10% and 20% products, energy per millilitre does not scale with strength — the labelled figures are 1.1, 2.0 and 3.0 kcal/mL, so 10% is not half of 20%. Entering grams of fat where the field asks for millilitres of emulsion is the other half of this trap, and at 20% it understates lipid energy fivefold.
The third is a convention rather than an error, and it moves the number most. Amino acids are counted at 4 kcal/g, and whether those calories belong in the energy total is genuinely unsettled: both practices exist. On the default bag the choice is worth 360 kcal/day, 21% of the total, so the same prescription is “1,710 kcal” or “1,350 kcal” depending on house style. It matters as soon as the figure meets a target: 24.4 kcal/kg/day total against 19.3 non-protein lands on opposite sides of a 20 to 25 kcal/kg window. See resting energy expenditure and protein requirements for the targets themselves.
The fourth is the substrate loads, which limit rate rather than energy. ESPEN says glucose “should not exceed 5 mg/kg/min”, while the German parenteral nutrition guideline puts normal utilisation lower at 4 to 5 g/kg/day, 2.8 to 3.5 mg/kg/min. Carbohydrate beyond oxidative capacity goes to lipogenesis, which raises CO₂ production and can lift the respiratory quotient above 1.0. Lipid ceilings disagree openly — 1.5 g/kg/day from ESPEN, 0.7 to 1.3 from the German guideline, “not to exceed 2.5 g/kg/day” on the Intralipid label — and all are tabulated with their sources. Paediatric glucose figures are entirely different: see the neonatal glucose infusion rate calculator. In anyone who has eaten little for days the first question is refeeding risk, not the energy target. This page computes a figure and prints the published targets beside it with the guideline each comes from. The prescription is the clinician’s, taken with the patient in front of them.
Frequently asked questions
How many calories are in a gram of dextrose in parenteral nutrition?
3.4 kcal/g, not 4. Parenteral dextrose is the monohydrate; the prescribing information for Dextrose Injection USP states “3.4 kcal/g of dextrose, hydrous” and gives 170 kcal per 100 mL for the 50% solution. The 4 kcal/g figure belongs to anhydrous glucose and overstates a 250 g bag by 150 kcal/day.
How many calories per mL is 20% lipid emulsion?
2.0 kcal/mL, per the Intralipid prescribing information. 10% is 1.1 kcal/mL and 30% is 3.0 — note that 10% is not half of 20%, because the glycerol and phospholipid are at the same absolute concentration in both products and form a larger share of the dilute one. A gram of emulsion lipid is about 10 kcal rather than 9 for the same reason.
Should protein calories be counted in the total?
Both conventions are in clinical use and the question is not settled. What matters is saying which one a figure uses: on the default bag here the difference is 360 kcal/day, 21% of the total, so the same prescription can be described as 1,710 kcal or 1,350 kcal. This page shows both.
What is the maximum glucose infusion rate in parenteral nutrition?
The published figures differ. ESPEN’s 2019 intensive care guideline: glucose “should not exceed 5 mg/kg/min” (rec. 23), which is 504 g of dextrose a day at 70 kg. The German parenteral nutrition guideline puts normal utilisation at approximately 4 to 5 g/kg/day — 2.8 to 3.5 mg/kg/min — preferring 3.0 to 3.5, with 1 to 2 g/kg/day initially in high-risk patients. Published figures rather than a prescription.
What is the maximum lipid dose?
The sources disagree and the page prints all of them. ESPEN: lipids “should not exceed 1.5 g lipids/kg/day”. The German guideline: 0.7 to 1.3 g/kg/day, up to 1.5 where energy requirements are high, with lipid providing 25 to 40% of non-protein energy. The Intralipid label: an adult dose “not to exceed 2.5 g/kg/day”. A separate limit of 0.11 g/kg/hour applies to the infusion rate.
Related calculators
References
- Pfizer Inc. Dextrose Injection USP prescribing information, 50% and 70%. “3.4 kcal/g of dextrose, hydrous”; 50% provides 170 kcal per 100 mL at 2,523 mOsmol/L and 70% provides 238 kcal per 100 mL at 3,532 mOsmol/L.
- US Food and Drug Administration. Intralipid 10%, 20% and 30% (lipid injectable emulsion) prescribing information, 2025. “1.1 kcal per mL” for 10% and “2,000 kcal/L” for 20%, each with 1.2% egg yolk phospholipids and 2.25% glycerin; adult dose “not to exceed 2.5 g/kg/day”. The Intralipid 30% label gives “3.0 kcal per mL” with 1.7% glycerin.
- Ministry of Health, Saudi Arabia. Clinical Practice Guideline: adult parenteral nutrition, September 2024. Dextrose 3.4 kcal/g, amino acids approximately 4 kcal/g, lipid in PN approximately 10 kcal/g; goal dextrose 5 mg/kg/min and lipid 1 g/kg/day with a maximum lipid infusion of 0.11 g/kg/hour; peripheral formulations between 750 and below 900 mOsm/L.
- Singer P, Blaser AR, Berger MM, et al. ESPEN guideline on clinical nutrition in the intensive care unit. Clin Nutr. 2019;38(1):48–79. Recommendations 15 (indirect calorimetry in ventilated patients, Grade B), 17 (not exceeding 70% of energy expenditure in the early phase), 22 (1.3 g/kg protein equivalents), 23 (glucose “should not exceed 5 mg/kg/min”) and 25 (lipids “should not exceed 1.5 g lipids/kg/day”). Predictive equations are “associated with significant inaccuracy (up to 60%)”, with 20–25 kcal/kg/day named as the simplest alternative.
- German Association for Nutritional Medicine (DGEM). Carbohydrates — Guidelines on Parenteral Nutrition. GMS Ger Med Sci. 2009. “Humans with normal metabolism utilise approximately 4–5 g/kg body weight/day of glucose”; 3.0 to 3.5 g/kg/day, which is 2.1–2.4 mg/kg/min, “is preferable”; 1–2 g/kg/day initially in high-risk patients.
- German Association for Nutritional Medicine (DGEM). Lipid Emulsions — Guidelines on Parenteral Nutrition, chapter 6. GMS Ger Med Sci. 2009. “0.7–1.3 g triglycerides/kg body weight” a day, up to 1.5 g/kg where energy requirements are high; lipid “about 25–40% of the parenteral non-protein energy supply”.
Not medical advice. For healthcare professionals and education. Reference intervals vary by laboratory and assay — always use your own laboratory's. Never base a dose or a treatment decision on this page alone. Full disclaimer at calcengines.com/disclaimer/