Quick start
- Open the GFR Calculator.
- Enter age and formula sex exactly as required by the equation.
- Use the first example, "Female 50: Creatinine 0.9 mg/dL", if you want to see a filled-out calculation before entering your own values.
- Calculate, read the formula line, then copy the result only after the units and assumptions look right.
Best uses
Use this guide when one of these tasks matches what you are trying to do.
- Estimate adult eGFR from a creatinine lab value.
- Use the 2021 CKD-EPI race-free equation.
- See a broad eGFR interpretation range.
- Prepare questions for a clinician about kidney labs.
What this calculator is for
The GFR Calculator estimates adult eGFR from age, sex, and serum creatinine using the 2021 CKD-EPI creatinine equation.
Use it when you want to: Estimate adult eGFR from a creatinine lab value. Use the 2021 CKD-EPI race-free equation.
What to enter
Good answers start with clean inputs. Before calculating, check the labels, units, and dates so the tool is solving the same problem you actually have.
- Enter age and formula sex exactly as required by the equation.
- Enter serum creatinine from a standardized lab result.
- Use the creatinine unit shown by the tool and do not convert by guessing.
Example walkthrough
Try the calculator example: Female 50: Creatinine 0.9 mg/dL. The example result is eGFR estimate.
- For a creatinine example, the calculator compares creatinine with the equation constant for the selected sex.
- Age and sex factors then adjust the final eGFR estimate.
Formula and steps
The calculator uses the 2021 CKD-EPI creatinine equation with age, sex, and serum creatinine. It does not use a race coefficient.
The formula line on the calculator page is there so the answer is not a mystery. Read it when you need to understand where the number came from.
How to read the answer
eGFR depends on standardized lab creatinine and clinical context. A clinician may compare it with urine albumin, repeat labs, medications, age, and health history.
- eGFR is reported as mL/min/1.73 m2.
- A clinician may compare eGFR with urine albumin, repeat labs, medications, and health history.
Common mistakes to avoid
Most bad calculator results come from a small input mistake or from using a good estimate for the wrong decision.
- Do not use eGFR to diagnose yourself from one calculator result.
- Do not enter non-standard or old lab values without checking units.
- Do not use this for children or pregnancy without clinician guidance.
What to try next
A related calculator can help check the same topic from another angle instead of relying on one number.
- Bring lab questions to a qualified clinician.
- Use Body Surface Area Calculator only as a separate educational reference.
Sources and safety notes
This guide uses public-health, clinical, or peer-reviewed references where the calculator needs a specific formula or interpretation boundary.
Source links are provided for transparency, but they do not turn the calculator into medical advice or a replacement for professional care.
Examples from the calculator
eGFR estimate
eGFR estimate
eGFR estimate
Common questions
What can I use the GFR Calculator for?
Use it for quick educational estimates, planning, comparison, and trend checks. Health and fitness results should be interpreted with context, not as a diagnosis.
How does the GFR Calculator calculate the result?
The calculator uses the 2021 CKD-EPI creatinine equation with age, sex, and serum creatinine. It does not use a race coefficient.
Is this medical advice?
No. This page provides an educational estimate only. Talk with a qualified health professional before making medical, pregnancy, nutrition, medication, or safety decisions.
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History, privacy, and copying
Recent answers stay visible in the page while you work. The history is kept only in the current browser tab and is not sent to a server.
Copy answer copies the expression and result so you can paste it into notes, homework, a message, or another document.