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eGFR kidney function calculator

Enter your age and blood creatinine. Choose your laboratory’s sex coefficient for an adult CKD-EPI 2021 estimate.

Educational estimate. Qualified clinical review has not been performed. Do not use this result to diagnose a condition or choose treatment.

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Calculator measurements
years

Age in completed years.

Serum or plasma creatinine, not a urine result.

Your result will appear here

Enter your measurements above, or try the worked example. Entry limits are not healthy reference ranges.

Inputs and results stay in this page's memory. They are not saved, uploaded or added to links. Changing units clears that value.

Conceptual illustration of two kidneys and fluid filtration with an orange accent.

What this result means

eGFR estimates how well the kidneys filter using blood measurements and a population equation. This calculator uses the 2021 CKD-EPI creatinine equation for adults. It is an estimate in mL/min/1.73 m², not a diagnosis, medication dose or direct measurement of kidney function. [1]

What this calculator uses

Age in completed years, serum or plasma creatinine and the laboratory's female or male coefficient. It does not ask for race. The result is normalised to a standard body surface area, which explains the 1.73 m² in the unit. [1]

Why creatinine is only part of the picture

Creatinine can be influenced by muscle mass, diet, supplements and other factors. An estimated result can differ from measured GFR. When greater accuracy matters, a clinician may use cystatin C with creatinine or a measured filtration test. [1]

Use previous results and urine albumin

A lower result needs clinical context. Chronic kidney disease generally requires persistence for at least three months or other evidence of kidney damage. Urine albumin and the pattern over time matter. A sudden decline or acute symptoms needs prompt assessment, not a three-month wait. [2]

What is a normal eGFR?

There is no single number that explains everyone's kidney health. Age, urine albumin and other evidence matter. A result at or above 90 does not rule out kidney damage, and a single lower result does not by itself establish chronic kidney disease. [1][2]

Does this tell me my kidney disease stage?

No. GFR categories are only part of a clinical assessment that includes persistence, cause and albuminuria. This calculator does not label a one-off result as a chronic disease stage. [2]

Why is this different from my laboratory's eGFR?

Check the equation version, exact unrounded creatinine, age, sex coefficient, units and rounding. Some laboratories use a different equation or report results above a threshold as >90 rather than an exact number. Your laboratory report remains the measurement record. [1]

Which sex coefficient should I use?

Use the coefficient appropriate to the laboratory's method and your clinical context. The equation was developed with female and male categories. Hormone treatment and other circumstances can make selection and creatinine interpretation uncertain; discuss them with your clinician rather than guessing.

Can I use it during an acute kidney problem or pregnancy?

Do not rely on this equation in those situations. The adult creatinine model assumes a suitable stable context, and it is not validated here for pregnancy or acute changes. Use professional assessment and an appropriate method. [1]

Can I use eGFR to change a medicine dose?

No. Dosing may require a different kidney estimate, body size adjustment, the specific product instructions and professional judgement. Do not substitute this indexed educational result for a dosing assessment. [1]

Formula and assumptions

Formula
eGFR = 142 × min(SCr/κ,1)^α × max(SCr/κ,1)^−1.200 × 0.9938^age × 1.012 if female. SCr in mg/dL; κ = 0.7 female, 0.9 male; α = −0.241 female, −0.302 male. µmol/L ÷ 88.4 = mg/dL. [1]
Version
2021 CKD-EPI creatinine equation without race, ckd-epi-creatinine-2021.v1
Rounding
Do not round creatinine before the equation. Display the final eGFR to one decimal; that display precision is not a claim of medical accuracy.
Worked example
For age 40 and serum creatinine 1.00 mg/dL (88.4 µmol/L), CKD-EPI 2021 gives approximately 97.6 mL/min/1.73 m² with the male coefficient and 73.0 with the female coefficient. The examples show why coefficient selection must be explicit. [1]

Who this is for — and when not to use it

Intended use

Educational adult creatinine-based eGFR estimation using stable, suitable blood creatinine and an explicitly selected equation coefficient.

Not intended for

Acute kidney injury assessment, paediatric or pregnancy estimation, medication dosing, transplant decisions or replacement of measured GFR.

Exclusions

  • Children; pregnancy; acute kidney injury or rapidly changing creatinine.
  • Urine creatinine or a result reported only as > or < a limit.
  • Situations where creatinine is a poor marker, including markedly unusual muscle mass or amputation.
  • Using the indexed result directly for a drug dose; using a sex coefficient without appropriate clinical context.

Evidence sources

  1. 1. eGFR equations for adults: 2021 CKD-EPI creatinine equation — US National Institute of Diabetes and Digestive and Kidney Diseases. Accessed Oct 4, 2026.
  2. 2. KDIGO 2024 clinical practice guideline for evaluation and management of CKD — Kidney Disease: Improving Global Outcomes. Accessed Oct 4, 2026.