Kidney & hydration
eGFR Calculator (Kidney Function)
Use this free eGFR calculator to estimate how well your kidneys are filtering, using the 2021 CKD-EPI equation from your creatinine, age and sex.
- Free to use
- Works on your phone
- Nothing saved or shared
How to use this eGFR calculator
This free eGFR calculator uses the 2021 CKD-EPI creatinine equation, the current race-free standard, to estimate your kidney filtration in three simple steps.
- Choose your sex and enter your age.
- Enter your serum creatinine from your blood test, and pick the matching unit.
- Press Estimate my eGFR to see your filtration rate and stage.
What your eGFR means
Your eGFR estimates how many millilitres of blood your kidneys clean each minute. Higher is better. The eGFR normal range starts at 90 or above, and doctors group the results into stages:
- 90 or above is normal filtration.
- 60 to 89 is mildly reduced, often normal for older adults.
- 45 to 59 and 30 to 44 are moderate reductions.
- 15 to 29 is a severe reduction, and below 15 is kidney failure.
Importantly, an eGFR between 60 and 89 only counts as kidney disease if there are other signs, such as protein in the urine. Your number on its own does not give a diagnosis.
eGFR stages chart
The eGFR stages below show how each range maps to a kidney function stage under the CKD-EPI standard. The calculator above gives your exact figure, while this chart is handy for a quick look.
| eGFR | Stage | What it means |
|---|---|---|
| 90 and above | G1 | Normal filtration |
| 60 to 89 | G2 | Mildly reduced |
| 45 to 59 | G3a | Mild to moderate |
| 30 to 44 | G3b | Moderate to severe |
| 15 to 29 | G4 | Severe |
| Below 15 | G5 | Kidney failure |
Looking after your kidneys
Your kidneys do quiet, vital work, clearing waste and balancing fluids and minerals. The best ways to protect them are also good for your heart: keeping blood pressure and blood sugar in range, staying hydrated, going easy on anti-inflammatory painkillers, and not smoking.
Answers
Frequently asked questions
What is a normal eGFR?
An eGFR of 90 or above is generally considered normal, and 60 to 89 is common and often still healthy, especially with age. Below 60 for three months or more can point to chronic kidney disease, but eGFR is only part of the picture and must be read by a doctor alongside other tests.
Which equation does this use?
It uses the 2021 CKD-EPI creatinine equation, the current race-free standard. It estimates how well your kidneys filter, adjusted for your age and sex, from a single creatinine blood test.
Why does eGFR fall with age?
Kidney filtration naturally slows as we get older, so a lower eGFR in an older adult is not always a sign of disease. That is one reason the number always needs to be understood in the context of your overall health.
What is a normal eGFR by age?
An eGFR of 90 or above is the textbook normal, but filtration naturally slows over the years, so a reading in the 60s or 70s can be perfectly normal for an older adult. The eGFR normal range is best read together with your age and your other results, rather than as a single pass-or-fail number.
What is a normal creatinine level?
For most adults, creatinine is roughly 0.6 to 1.2 mg/dL, though it depends on your muscle mass, sex and age, so people with more muscle naturally sit a little higher. Your lab and your doctor are the ones who judge what is normal for you.
Can I improve my eGFR?
You can protect your kidneys by keeping blood pressure and blood sugar in a healthy range, staying hydrated, being careful with painkillers like ibuprofen, and not smoking. Whether eGFR itself can rise depends on the cause, so this is a conversation for your doctor.
What is the difference between CKD-EPI and MDRD?
Both estimate your eGFR from your creatinine blood test. CKD-EPI is the newer, more accurate equation, and the 2021 version is race-free, which is why this tool uses it. MDRD is an older method that you may still see on some lab reports.