eGFR calculator: kidney function from your creatinine
eGFR estimates how well your kidneys filter blood, worked out from your serum creatinine, age and sex. 90 or more is normal, 60 to 89 is mildly decreased, and below 60 for more than 3 months points to chronic kidney disease. Enter the creatinine from your report below to get your eGFR and KDIGO category. One value is not a diagnosis; your doctor reads it with your urine test and history.
Calculate your eGFR from creatinine
For adults 18 and over, with a stable creatinine. Not for children, pregnancy, dialysis, or sudden illness (acute kidney injury).
| Your result | |
|---|---|
| eGFR (CKD-EPI 2021) | |
| KDIGO GFR category |
One eGFR value does not diagnose kidney disease. Doctors look at the trend over at least 3 months, a urine albumin test and the cause. Ask your doctor to interpret it.
Ask a dietitian about a kidney dieteGFR stages (KDIGO)
Doctors group eGFR into six categories. Albumin in the urine adds a second letter-and-number grade (A1 to A3), and kidney disease is diagnosed only when the change lasts more than 3 months.
| Category | eGFR (mL/min/1.73 m²) | Meaning |
|---|---|---|
| G1 | 90 or more | Normal or high; kidney disease only if urine or scan shows damage |
| G2 | 60 to 89 | Mildly decreased; common with age |
| G3a | 45 to 59 | Mildly to moderately decreased |
| G3b | 30 to 44 | Moderately to severely decreased |
| G4 | 15 to 29 | Severely decreased; see a kidney specialist |
| G5 | Below 15 | Kidney failure; dialysis or transplant is considered |
Examples with real numbers
| Person | Creatinine | eGFR | Category |
|---|---|---|---|
| Woman, 40 years | 1.0 mg/dL | About 73 | G2 |
| Man, 50 years | 1.2 mg/dL | About 74 | G2 |
| Man, 60 years | 2.0 mg/dL | About 38 | G3b |
Notice that a creatinine of 1.0 or 1.2 mg/dL, which many reports mark as "normal", can already mean a mildly reduced eGFR. That is why eGFR is more useful than the creatinine value alone. See the creatinine normal range page for lab ranges.
The formula
The CKD-EPI 2021 creatinine equation, with creatinine (Scr) in mg/dL:
eGFR = 142 × min(Scr/κ, 1)α × max(Scr/κ, 1)−1.200 × 0.9938age × 1.012 (if female)
For women κ = 0.7 and α = −0.241; for men κ = 0.9 and α = −0.302. "min" and "max" mean the smaller or larger of Scr/κ and 1. The 2021 version removed the race factor that earlier equations used.
Things that change creatinine without harming the kidneys
- Muscle mass: a bodybuilder has a higher creatinine than a thin older person with the same kidney function.
- A big cooked-meat meal before the test, or creatine supplements, can raise creatinine for a day.
- Dehydration, fever or hard exercise the day before.
- Some medicines (for example trimethoprim) raise creatinine without lowering real filtration.
If your result looks worse than expected, repeat the test fasting, hydrated and without heavy exercise, and ask whether a cystatin C test or urine albumin test is needed.
What to eat if your eGFR is low
The diet depends on your stage, whether you pass urine normally, your potassium and phosphate results and whether you are on dialysis. These are the general principles in KDIGO 2024, and your nephrologist or kidney dietitian sets your own numbers:
- Salt: keep sodium below 2 g a day (about 5 g of salt). Cut achaar, papar, chips, instant noodles, processed meat and extra salt at the table.
- Protein: in CKD stages 3 to 5 not on dialysis, about 0.8 g per kg of body weight a day is suggested, and very high-protein diets and powders are avoided. On dialysis, needs are higher.
- Potassium and phosphate: restrict only when blood tests show they are high. Needlessly avoiding fruit and vegetables is not advised.
- Blood sugar and blood pressure: these damage kidneys most, so the diabetes and BP diets matter. See the diabetes diet and high blood pressure diet.
- Avoid ibuprofen, diclofenac and other painkillers, and herbal or "kidney cleanse" products, unless your doctor agrees.
Full guidance with Pakistani meals, dialysis days and CKD versus AKI: kidney patient diet chart.
See a doctor first if
- Your creatinine rose quickly in a few days, you pass very little urine, or you are vomiting or have severe diarrhoea (possible acute kidney injury)
- Your eGFR is below 60 on more than one test, or below 30 on any test
- You have swelling of the face or feet, foamy urine, blood in urine, or breathlessness
- You have diabetes, high blood pressure, a family history of kidney disease, or take painkillers every day
- You are pregnant, on dialysis or have had a kidney transplant
Common questions
What is a normal eGFR?
An eGFR of 90 or more is considered normal or high, and 60 to 89 is mildly decreased. eGFR falls slowly with age, so a value of 70 to 80 in a 60-year-old can be normal for that age. Kidney disease is diagnosed when eGFR stays below 60 for more than 3 months, or when there are other signs of damage such as protein in the urine.
What is eGFR and how is it different from creatinine?
Creatinine is a waste product from muscle that you measure in blood. eGFR is an estimate of how many millilitres of blood your kidneys filter per minute, worked out from creatinine, age and sex. Two people with the same creatinine can have different eGFR, which is why doctors prefer eGFR to judge kidney function.
Which formula does this calculator use?
The CKD-EPI 2021 creatinine equation, published in the New England Journal of Medicine and recommended by KDIGO. It does not use race. Older reports may use MDRD or the 2009 CKD-EPI equation, so a lab's own eGFR can differ by a few points from this result.
How do I convert creatinine from µmol/L to mg/dL?
Divide µmol/L by 88.4. For example, 88 µmol/L is about 1.0 mg/dL. Most laboratories in Pakistan report mg/dL, and the calculator lets you choose either unit.
Can eGFR be wrong?
Yes. Creatinine depends on muscle. eGFR can look low in a bodybuilder or someone who ate a large cooked-meat meal or takes creatine, and can look falsely normal in an elderly or very thin person with little muscle. Dehydration, fever, some medicines and a very recent illness also change it. A doctor may repeat the test or ask for a cystatin C test or a urine albumin test.
My eGFR is below 60. Do I have kidney disease?
Not from one result. Chronic kidney disease needs an eGFR below 60 that lasts for at least 3 months, or evidence of kidney damage such as albumin in the urine. Repeat the test, bring your reports to a doctor, and do not change your medicines or start a restrictive diet on your own.
Can I improve my eGFR with diet?
Diet cannot restore lost kidney filtering, but it can slow the damage and protect the kidneys. The most important steps are controlling blood pressure and blood sugar, keeping salt low, avoiding painkillers such as ibuprofen and diclofenac unless a doctor advises, and not taking herbal or unlabelled products. In CKD stages 3 to 5, KDIGO suggests a protein intake of about 0.8 g per kg a day, to be individualised by your nephrologist or kidney dietitian.
What do the stages G1 to G5 mean?
G1 is 90 or more, G2 is 60 to 89, G3a is 45 to 59, G3b is 30 to 44, G4 is 15 to 29 and G5 is below 15 (kidney failure). Doctors also use a urine albumin result (A1 to A3) because protein in the urine raises the risk at every stage.
Is the eGFR calculator valid for children, pregnancy or dialysis?
No. This formula is for stable adults. Children need a different equation, pregnancy changes creatinine, and on dialysis the number does not reflect kidney function. If creatinine has risen quickly over days (for example during dengue, vomiting or dehydration), that could be acute kidney injury and needs a doctor urgently.
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Sources
- Inker LA et al. New creatinine- and cystatin C-based equations to estimate GFR without race. N Engl J Med, 2021
- KDIGO 2024 Clinical Practice Guideline for the Evaluation and Management of Chronic Kidney Disease
- KDIGO Clinical Practice Guideline for Acute Kidney Injury, 2012
- National Kidney Foundation. Estimating GFR
- NHS. Chronic kidney disease