Every equation, side by side
Optional — adds the CrCl comparison.
Estimated GFR — CKD-EPI 2021 (creatinine + cystatin C)
Example78.0mL/min/1.73m²
KDIGO G2 · Mildly decreased
CKD-EPI 2021 — creatinine
73.1 mL/min/1.73m²
Race-free. Current standard when only creatinine is available.
G2CKD-EPI 2012 — cystatin C
75.3 mL/min/1.73m²
Useful where creatinine is unreliable — atypical muscle mass.
G2CKD-EPI 2021 — creatinine + cystatin CPreferred
78.0 mL/min/1.73m²
The most accurate of the three. Preferred when both are available.
G2MDRD — legacy
66.6
Superseded by CKD-EPI 2021. Shown for comparison with older results.
De-indexing makes the two figures comparable — it does not make them interchangeable. Where a product label specifies creatinine clearance, dose against CrCl.
Stays in your browser
You cannot convert directly, because the two are reported in different units: eGFR is indexed to body surface area (mL/min/1.73 m²) and creatinine clearance is not (mL/min). To make them comparable, de-index eGFR by multiplying by the patient’s BSA and dividing by 1.73, or index CrCl the other way. Even then they are not interchangeable — creatinine clearance exceeds true GFR because creatinine is both filtered and secreted.
Overview
GFR — glomerular filtration rate — is the volume of plasma filtered by the glomeruli per minute. It is the best single measure of kidney function, but measuring it directly requires an exogenous marker and is impractical in routine care.
eGFRis an estimate of that value from a blood test, reported in mL/min/1.73 m² — indexed to a standard body surface area so that results are comparable between people of different sizes. It is what CKD staging is built on.
Creatinine clearance is a different quantity: the volume of plasma cleared of creatinine per minute, in mL/min, not indexed. It systematically exceeds true GFR because the renal tubules secrete creatinine in addition to filtering it. It remains the reference for renal drug dosing, because that is what the dosing studies used.
Equations
eGFR = 142 × min(Scr/κ, 1)^α
× max(Scr/κ, 1)^−1.200
× 0.9938^age
× 1.012 [if female]
κ = 0.7 (female) | 0.9 (male)
α = −0.241 (female) | −0.302 (male)Scr in mg/dL. Result in mL/min/1.73 m².
Source: Inker LA, et al. N Engl J Med. 2021;385:1737–49.
eGFR = 133 × min(Scys/0.8, 1)^−0.499
× max(Scys/0.8, 1)^−1.328
× 0.996^age
× 0.932 [if female]Cystatin C in mg/L. Less affected by muscle mass than creatinine, so useful in amputees, cachexia, and heavily muscled patients.
Source: Inker LA, et al. N Engl J Med. 2012;367:20–9.
eGFR = 135 × min(Scr/κ, 1)^α
× max(Scr/κ, 1)^−0.544
× min(Scys/0.8, 1)^−0.323
× max(Scys/0.8, 1)^−0.778
× 0.9961^age
× 0.963 [if female]
κ = 0.7 (female) | 0.9 (male)
α = −0.219 (female) | −0.144 (male)The most accurate of the three. Preferred whenever both markers are available.
Source: Inker LA, et al. N Engl J Med. 2021;385:1737–49.
eGFR = 0.413 × height(cm) / Scr(mg/dL)
Validated in children with CKD using IDMS-traceable creatinine. Cockcroft-Gault and CKD-EPI must not be used under 18.
Source: Schwartz GJ, et al. J Am Soc Nephrol. 2009;20(3):629–37.
eGFR → mL/min : eGFR × BSA / 1.73 CrCl → /1.73m²: CrCl × 1.73 / BSA BSA (Du Bois) = 0.007184 × ht(cm)^0.725 × wt(kg)^0.425
This aligns the units. It does not make the two figures equivalent.
Staging
| Category | eGFR (mL/min/1.73 m²) | Term |
|---|---|---|
| G1 | ≥ 90 | Normal or high |
| G2 | 60–89 | Mildly decreased |
| G3a | 45–59 | Mildly to moderately decreased |
| G3b | 30–44 | Moderately to severely decreased |
| G4 | 15–29 | Severely decreased |
| G5 | < 15 | Kidney failure |
Worked examples
68-year-old man, serum creatinine 1.1 mg/dL, using CKD-EPI 2021.
κ = 0.9, α = −0.302
Scr/κ = 1.1 / 0.9 = 1.222
eGFR = 142 × 1^−0.302
× 1.222^−1.200
× 0.9938^68
= 142 × 1 × 0.786 × 0.65573.1mL/min/1.73m²
KDIGO category G2 — mildly decreased.
Same patient, with a cystatin C of 1.0 mg/L available.
Creatinine only → 73.1
Cystatin C only → 75.3
Combined 2021 →
135 × 1^−0.144 × 1.222^−0.544
× 1^−0.323 × 1.25^−0.778
× 0.9961^68 × 178.0mL/min/1.73m²
The combined equation is the most accurate of the three and is preferred when both markers are available.
Same patient, 75 kg and 178 cm, needing a CrCl figure for a drug label.
BSA = 0.007184 × 178^0.725 × 75^0.425
= 1.93 m²
De-indexed = 78.0 × 1.93 / 1.73
Cockcroft-Gault, same patient = 66.586.9mL/min
The de-indexed eGFR and the Cockcroft-Gault CrCl disagree by roughly 20 mL/min. Where a label specifies creatinine clearance, dose against Cockcroft-Gault.
Accuracy
More calculators
Estimating GFR is one half of the picture. For dosing use the Cockcroft-Gault calculator; for patients where creatinine is unreliable, see special populations or measure directly with the 24-hour urine calculator.
Standard adult creatinine clearance with actual, ideal and adjusted body weight side by side.
Open calculatorWeight-basis selection, Salazar-Corcoran, amputation correction, paediatric equations and mL/hour output.
Open calculatorMeasured clearance from a timed collection, with a collection-adequacy check and BSA normalisation.
Open calculatorYou cannot convert directly — they are different measures. eGFR is reported per 1.73 m² of body surface area; CrCl is not. To make them roughly comparable, de-index eGFR by multiplying by the patient’s BSA and dividing by 1.73. Even then, use CrCl for drug dosing where the label specifies it.
The same de-indexing applies: CrCl-equivalent ≈ eGFR × BSA / 1.73. Note that creatinine clearance systematically exceeds true GFR, because creatinine is both filtered and actively secreted by the renal tubules. The two figures are not interchangeable even after conversion.
Index the CrCl to body surface area: multiply by 1.73 and divide by the patient’s BSA. This puts it in the same units as eGFR but does not make it an eGFR — tubular secretion of creatinine means clearance overestimates true GFR, typically by 10–20%.
CKD-EPI estimates glomerular filtration rate in mL/min/1.73 m². The 2021 creatinine version is eGFR = 142 × min(Scr/κ,1)^α × max(Scr/κ,1)^−1.200 × 0.9938^age × 1.012 if female, where κ is 0.7 for females and 0.9 for males (Inker et al., NEJM 2021). It contains no race coefficient.
eGFR = 133 × min(Scys/0.8,1)^−0.499 × max(Scys/0.8,1)^−1.328 × 0.996^age × 0.932 if female, with cystatin C in mg/L (Inker et al., NEJM 2012). Cystatin C is less affected by muscle mass than creatinine, which makes it useful where creatinine is unreliable.
Yes, for most purposes. CKD-EPI is more accurate at higher GFR values, where MDRD systematically underestimates. The 2021 CKD-EPI equations also removed the race coefficient that MDRD retains. MDRD is included on this page only for comparison with historical results.
90 mL/min/1.73 m² or above is KDIGO category G1, described as normal or high. However, eGFR alone does not diagnose chronic kidney disease — KDIGO staging combines the GFR category with albuminuria and requires abnormalities to persist for at least three months.
By GFR category and albuminuria together (KDIGO 2012). GFR categories run G1 (≥90) through G5 (<15) in mL/min/1.73 m², with G3 split into G3a (45–59) and G3b (30–44). Both must persist for three months or more for a chronic kidney disease diagnosis.
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