Creatinine Unit Converter

Convert serum creatinine between mg/dL and µmol/L, with adult reference ranges and what a change actually means.

Last updated 31 Aug 2026

Creatinine converter

Mass ⇄ molar

Serum creatinine

µmol/L ÷ 88.4 = mg/dL.

Reference groupRanges are laboratory-specific; confirm against your own report.

114.9µmol/LExample

Creatinine 1.3 mg/dL

Formula and conversion factor

µmol/L = mg/dL × 88.40
mg/dL = µmol/L ÷ 88.40

88.40: derived from the molecular weight of creatinine, 113.12 Da
mg/L: mg/dL × 10

Worked example

Creatinine 1.3 mg/dL
1.3 × 88.40 = 114.9 µmol/L
= 13.0 mg/L

Reference ranges

Reference intervals assume average muscle mass. They are not meaningful in cachexia, amputation, paraplegia or unusually high muscle bulk.
Group	mg/dL	µmol/L
Men, adult	0.74 – 1.35	65 – 119
Women, adult	0.59 – 1.04	52 – 92
Children 3 – 18 years	0.5 – 1.0	44 – 88
Infants	0.2 – 0.4	18 – 35

What creatinine measures

Creatinine is the breakdown product of creatine phosphate in muscle, produced at a rate proportional to muscle mass and cleared almost entirely by glomerular filtration with a small tubular secretory component. That proportionality is both why it works as a filtration marker and why it fails in the patients where it matters most.

The relationship between creatinine and GFR is hyperbolic, not linear, and this is the single most important thing to understand about the number. A rise from 0.7 to 1.4 mg/dL keeps the result inside most reference ranges while representing a loss of roughly half of kidney function. The same absolute rise from 4.0 to 4.7 represents a far smaller change. A creatinine within the reference interval never excludes significant chronic kidney disease, and a rising creatinine within range in a patient with a previous value is a more useful signal than a single number.

Several drugs raise creatinine by blocking its tubular secretion without touching GFR — trimethoprim, cimetidine, dolutegravir, cobicistat and ritonavir among them. The rise appears within days, plateaus, and reverses on stopping. Recognising it prevents unnecessary investigation and inappropriate discontinuation of effective treatment.

Frequently asked questions

How do I convert creatinine from mg/dL to µmol/L?

Multiply by 88.4. A creatinine of 1.3 mg/dL is 114.9 µmol/L. Divide by 88.4 to go the other way.

Can creatinine be normal with kidney disease?

Yes, routinely. The relationship with GFR is hyperbolic, so kidney function can fall by half while creatinine stays within the reference range. This is why eGFR is calculated rather than reading creatinine alone.

Which drugs raise creatinine without harming the kidneys?

Trimethoprim, cimetidine, dolutegravir, cobicistat and ritonavir all block tubular creatinine secretion. The rise appears within days, then plateaus, and reverses on stopping.

Why is my creatinine low?

Most often low muscle mass — from cachexia, amputation, paraplegia, advanced age or prolonged illness. It means an eGFR calculated from creatinine will overestimate true kidney function, and cystatin C is the better test.

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References

KDIGO 2024 Clinical Practice Guideline for the Evaluation and Management of Chronic Kidney Disease.
Inker LA et al. New creatinine- and cystatin C-based equations to estimate GFR without race. N Engl J Med. 2021;385(19):1737–49.