Complete guide
GFR Calculator: formula, worked example and interpretation
Estimate adult eGFR with the race-free 2021 CKD-EPI creatinine equation published by NIDDK. Enter the known values and the result updates instantly with an auditable breakdown.
What the GFR Calculator answers
Estimate adult eGFR with the race-free 2021 CKD-EPI creatinine equation published by NIDDK.
Use the breakdown to compare the result with the source values before making a decision.
Formula and variables
The calculation uses eGFR=142×min(SCr/κ,1)^α×max(SCr/κ,1)^−1.200×0.9938^age×1.012 if female. Every variable comes directly from a labeled field.
eGFR=142×min(SCr/κ,1)^α×max(SCr/κ,1)^−1.200×0.9938^age×1.012 if femaleWorked example
Age 55, female equation and creatinine 1.0 mg/dL are evaluated with κ=0.7 and α=−0.241.
Changing any field recalculates the result immediately, so nearby scenarios can be compared without reloading the page.
How to use the result
Treat the result as a planning value and compare it with the detailed rows shown beside it.
Keep units and time periods consistent. Use the share or PDF action to preserve the exact assumptions.
Assumptions and scope
eGFR is an estimate for adults. NIDDK recommends combined creatinine-cystatin C in situations where accuracy near a decision threshold matters.
The calculator exposes its assumptions instead of filling missing facts with hidden estimates.
Accuracy checks
Confirm the units, dates, rates and source figures before relying on the output.
Round only the displayed answer; Calculator24 keeps full JavaScript precision for intermediate arithmetic and exported values.
Input and output checklist
| Item | What to enter or review |
|---|---|
| Inputs | Equation sex, Age (years), Serum creatinine (mg/dL) |
| Equation | eGFR=142×min(SCr/κ,1)^α×max(SCr/κ,1)^−1.200×0.9938^age×1.012 if female |
| Example | Age 55, female equation and creatinine 1.0 mg/dL are evaluated with κ=0.7 and α=−0.241. |
| Limit | eGFR is an estimate for adults. NIDDK recommends combined creatinine-cystatin C in situations where accuracy near a decision threshold matters. |
Frequently asked questions
What does this GFR Calculator calculate?
Estimate adult eGFR with the race-free 2021 CKD-EPI creatinine equation published by NIDDK.
Which formula does it use?
eGFR=142×min(SCr/κ,1)^α×max(SCr/κ,1)^−1.200×0.9938^age×1.012 if female
Does the result update while I type?
Yes. Valid changes recalculate after a short delay and the previous result is not substituted for invalid input.
Which assumptions should I check?
Check units, rates, dates and every source value shown in the form.
Is the result exact?
eGFR is an estimate for adults. NIDDK recommends combined creatinine-cystatin C in situations where accuracy near a decision threshold matters.
Can I save or share the calculation?
Yes. Copy, Share, WhatsApp, PDF/Print, CSV, comparison and parameterized-link actions are available.
What to keep in mind
eGFR is an estimate for adults. NIDDK recommends combined creatinine-cystatin C in situations where accuracy near a decision threshold matters.
Results display up to 8 decimal places; exported numbers preserve calculation precision. This is a calculation summary, not an official certificate.