GFR Calculator

Modify the values and click the Calculate button to use

CKD-EPI GFR: 99.2 mL/min/1.73m²

MDRD 4-variable: 89.3 mL/min/1.73m²
CKD-EPI: 99.2 mL/min/1.73m²
Mayo quadratic: 120.3 mL/min/1.73m²
CKD stage: Normal or CKD 1

eGFR is an estimate based on serum creatinine. It can be affected by muscle mass, diet, medications, and acute illness. It is not a diagnosis of kidney disease.

CKD stages

Stage	eGFR (mL/min/1.73m²)
Normal	90+ with no proteinuria
CKD 1	90+ with evidence of kidney damage
CKD 2 (mild)	60–89 with evidence of kidney damage
CKD 3 (moderate)	30–59
CKD 4 (severe)	15–29
CKD 5 (failure)	below 15

What this GFR calculator does

Glomerular filtration rate (GFR) estimates how much blood the kidneys filter per minute. This calculator estimates GFR from serum creatinine, age, sex, and race using the MDRD 4-variable equation, the CKD-EPI equation, and the Mayo quadratic formula. It also shows the standard CKD stage ranges.

eGFR is a screening estimate, not a diagnosis. It can be affected by muscle mass, diet, medications, and acute illness.

How to use this calculator

Enter serum creatinine and choose mg/dL or µmol/L.
Enter age, sex, and race.
Click Calculate to see the three estimates and the CKD stage.

The default example is a 50-year-old man with a creatinine of 0.9 mg/dL.

GFR formulas

MDRD:
  175 × Scr^-1.154 × age^-0.203 × 0.742 (female) × 1.212 (Black)

CKD-EPI:
  141 × min(Scr/k, 1)^a × max(Scr/k, 1)^-1.209
      × 0.993^age × 1.018 (female) × 1.159 (Black)

Mayo:
  exp(1.911 + 5.249/Scr − 2.114/Scr² − 0.00686 × age − 0.205 (female))

k is 0.9 for men and 0.7 for women; a is −0.411 for men and −0.329 for women.

CKD stages

Stage	eGFR (mL/min/1.73 m²)
Normal	90+ with no proteinuria
CKD 1	90+ with kidney damage
CKD 2	60–89 with kidney damage
CKD 3	30–59
CKD 4	15–29
CKD 5	below 15

What the results mean

The default example gives about 89.3 (MDRD), 99.2 (CKD-EPI), and 120.3 (Mayo) mL/min/1.73 m². Differences between equations are expected; CKD-EPI is commonly used in practice.

Assumptions and limitations

The equations were developed in specific populations and may be less accurate in very muscular or very frail people, pregnancy, children, and acute kidney injury. The race coefficient is controversial and may not be appropriate for every patient. This calculator does not measure proteinuria or kidney damage.

Do not use this page to diagnose or stage kidney disease. Discuss results with a clinician and use the equation your laboratory reports.

Frequently asked questions

Which equation should I use?

CKD-EPI is widely used. MDRD is older but still common. The Mayo formula is an alternative. Your clinician or laboratory may prefer a specific equation.

Does a low eGFR mean kidney disease?

Not necessarily. eGFR can fall temporarily with dehydration or acute illness. CKD requires persistent findings and evidence of kidney damage.

Why does race appear in the formula?

Older equations included a race coefficient. Its use is now debated because race is a social category, not a biological variable. Follow your clinician's guidance.

Can I use this for children?

No. Children use different equations, often based on height and cystatin C.

Reference table

Serum creatinine units

Serum creatinine (S Cr )	mg/dL µmol/L
0.5 mg/dL	44.2 µmol/L
1.0 mg/dL	88.4 µmol/L
1.5 mg/dL	132.6 µmol/L
2.0 mg/dL	176.8 µmol/L
3.0 mg/dL	265.2 µmol/L

Conversion: µmol/L = mg/dL × 88.4. eGFR equations also use age and sex and are not interchangeable between labs.

Source

References:

Disclaimer

This calculator is for informational and educational purposes only. It is not a diagnosis or medical advice. Confirm kidney function with a qualified clinician.

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