Estimate eGFR from serum creatinine using the adult, race-free CKD-EPI 2021 equation. Enter the value and unit from the same blood-test report. The US mg/dL option is selected first; the calculator also accepts creatinine in µmol/L.
This tool reports an estimate in mL/min/1.73 m2, not a percentage of kidney function. It does not diagnose chronic kidney disease or replace your laboratory report and clinical assessment. Do not use the result to change medicine or insulin doses.
Do not rely on this calculator during pregnancy or suspected acute kidney injury. Creatinine-based estimates are most useful when kidney function is stable.
eGFR calculator (CKD-EPI 2021, race-free)
What this eGFR calculator measures
eGFR means estimated glomerular filtration rate. This version uses serum creatinine, age and the sex variable in the 2021 CKD-EPI creatinine equation. It does not use race as an input. The National Kidney Foundation describes this equation for adults; it should not be confused with a creatinine-cystatin C equation or a creatinine-clearance calculator.
Use your age in completed years and the creatinine unit actually printed on the report. This interface accepts ages 18 to 100; it is not a children's calculator. If your laboratory reports a different eGFR, ask which equation it used rather than assuming either number is an error.
Units and worked examples
The same creatinine concentration can be written as 1.00 mg/dL or 88.4 µmol/L. The calculator divides a µmol/L value by 88.4 before using the equation. It rounds the final eGFR to a whole number. NIDDK provides the equation and unit conversion.
For an arithmetic example, entering age 60, female, and creatinine 1.00 mg/dL gives a rounded estimate of 64 mL/min/1.73 m2. Entering 88.4 µmol/L with the same age and sex gives the same estimate. This example is not a diagnosis or a personal target.
GFR categories are not a diagnosis on their own
The categories below describe the filtration estimate. A single result does not establish chronic kidney disease. CKD involves abnormalities of kidney structure or function lasting at least three months. G1 or G2 alone is not CKD without other evidence of kidney damage. The National Kidney Foundation explains how repeat blood and urine tests fit together.
| GFR category | eGFR, mL/min/1.73 m2 | Description of filtration |
|---|---|---|
| G1 | 90 or above | Normal or high |
| G2 | 60 to 89 | Mildly decreased |
| G3a | 45 to 59 | Mildly to moderately decreased |
| G3b | 30 to 44 | Moderately to severely decreased |
| G4 | 15 to 29 | Severely decreased |
| G5 | Below 15 | Kidney-failure range; requires clinical assessment |
Do not wait three months to seek advice about a new or unexpectedly low result. The three-month definition distinguishes chronic disease from other problems; it is not an instruction to delay assessment.
Near a category boundary, a rounded online estimate is not enough for classification. Your care team can consider the laboratory result, its trend and whether a more accurate assessment is needed.
Why urine albumin and trends matter
Urine albumin-to-creatinine ratio, or uACR, looks for albumin leakage and adds information that eGFR alone cannot provide. The unit on the urine report also matters: do not treat a bare uACR number as a diagnosis. Compare repeat results with your care team, ideally knowing whether the same eGFR equation was used.
Limits of a creatinine-only estimate
Creatinine-based estimates can differ from measured kidney filtration and are affected by individual characteristics and clinical circumstances. A change in an estimate is not automatically a permanent change in kidney function. NIDDK explains sources of uncertainty and why trends matter.
Pregnancy, rapidly changing kidney function, serious illness and unusual muscle mass can make a creatinine-based estimate unreliable. This includes circumstances such as an amputation or marked muscle loss. Ask your clinician which assessment is appropriate rather than relying on this tool. See NIDDK's explanation of the clinical limitations.
A combined creatinine-cystatin C estimate may be more informative, particularly near an important clinical decision point. This calculator does not perform that combined calculation. Your clinician may recommend another test or assessment instead of relying on this number alone.
Questions to take to your care team
- Which equation did my laboratory use?
- How does this compare with my earlier results?
- Do I need a repeat creatinine or a urine albumin test, and when?
- Would cystatin C help in my circumstances?
- Does my medicine list need a professional review?
If you are acutely unwell or have been told to seek urgent help, do not wait for an online estimate before getting assessed.