eGFR calculator
Start with sex, age and creatinine or cystatin C
The result comes from the equation suggested for the patient: EKFC for adults, and CKiD U25 for children and young people when height is entered. The other equations that apply are listed below it for comparison.
Or try an example: , or .
The 19 equations
Select one for its formula, validated population and references.
Creatinine
Creatinine + cystatin C
Kidney transplant recipients
About eGFR
How eGFR is calculated
Each eGFR equation was developed by comparing a blood test with measured GFR in a group of patients. It uses serum creatinine, cystatin C or both, together with age and usually sex. In North America, the usual choice is the race-free CKD-EPI 2021 creatinine equation:
eGFR = 142 × min(Scr/κ, 1)^α × max(Scr/κ, 1)^(-1.200) × 0.9938^age × sex
Scr is serum creatinine in mg/dL. For women κ = 0.7, α = −0.241 and the sex factor is 1.012; for men κ = 0.9, α = −0.302 and the sex factor is 1.
All 19 equations in the calculator have their own page, with the formula, the constants and the population each was validated in. For example CKD-EPI 2021, EKFC, MDRD, Cockcroft-Gault and, for children, CKiD U25. See all equations.
KDIGO GFR categories
KDIGO 2024 sorts GFR into six categories. They do not apply to children under 2. The guide has the albuminuria categories and explains which equation the calculator suggests.
| Category | GFR (mL/min/1.73 m²) | Terms |
|---|---|---|
| G1 | ≥90 | Normal or high |
| G2 | 60–89 | Mildly decreased |
| G3a | 45–59 | Mild to moderately decreased |
| G3b | 30–44 | Moderately to severely decreased |
| G4 | 15–29 | Severely decreased |
| G5 | <15 | Kidney failure |
Questions
- What is eGFR and how is it calculated?
- eGFR is an estimate of how well the kidneys filter blood. It comes from an equation that uses a blood test (creatinine, cystatin C or both) together with age and usually sex. Some equations also use height or weight.
- What is a normal eGFR?
- In adults, an eGFR of 90 mL/min/1.73 m² or more is KDIGO category G1 (normal or high), and 60 to 89 is G2 (mildly decreased). GFR falls with age, so G2 is common in older adults. An eGFR of 60 or more is only CKD if there are signs of kidney damage, such as albuminuria, for more than 3 months. In children, normal values change with age, and the adult categories do not apply under age 2.
- Which eGFR equation should I use?
- The calculator suggests one and shows its result at the top. For adults, that is EKFC, or EKFC Creatinine-Cystatin C when both markers are measured. Under 18, it is CKiD U25 if you enter height, and otherwise EKFC. For babies up to 4 weeks old, it is the neonatal equation. The other validated equations are listed below for comparison, and you can show any of them at the top instead.
- Does the calculator support both µmol/L and mg/dL?
- Yes. You can enter creatinine in µmol/L or mg/dL, and UACR in mg/mmol or mg/g. The calculator starts in the units most labs use where you are. Switching the unit converts the value you have entered. If the value only makes sense in the other unit, for example 150 entered as mg/dL, switching keeps the number as you typed it.
- Can I use it for children and newborns?
- Yes. It includes Bedside Schwartz and CKiD U25 for children and young people. A neonatal equation covers babies born at term, up to 4 weeks old. Most paediatric equations need height.
- Does it show the CKD stage?
- Yes. The result at the top shows its KDIGO GFR category (G1 to G5). If you enter UACR, it also shows the albuminuria category and the KDIGO risk table.
- Can I rely on this alone for clinical decisions?
- No. eGFR is an estimate. Read it together with the patient's history, their medicines and how their eGFR has changed over time, and use your clinical judgement.