The DaVita GFR calculator is a quick way to estimate how well your kidneys are filtering waste from your blood, using the same glomerular filtration rate (GFR) math that nephrologists rely on every day. Enter a few lab values into the tool above and it returns an estimated GFR (eGFR) — the number doctors use to gauge kidney function and stage chronic kidney disease (CKD). This page explains what the result means, how the underlying formula works, and when it may be time to loop in a kidney specialist. It’s an educational reference, not a diagnosis, so always confirm your numbers with your prescriber or care team.
Full disclaimer, limitations & how to report an error
This calculator estimates glomerular filtration rate (eGFR) using the 2021 CKD-EPI creatinine equation, and optionally the 2021 CKD-EPI creatinine-cystatin C equation, as published by the Chronic Kidney Disease Epidemiology Collaboration and endorsed by the National Kidney Foundation–American Society of Nephrology Task Force. It is intended for adults aged 18 and over.
- This is an educational reference and decision-support aid, not a diagnosis. It does not tell you what treatment to pursue, whether to start dialysis, or how to adjust any medication.
- All estimating equations are imprecise, especially at higher eGFR values, and can be affected by pregnancy, amputation, unusual muscle mass, recent large changes in kidney function, or non-standardized lab assays.
- Results are only as accurate as the values you type in. Always confirm inputs against your actual lab report or clinician-provided figures.
- Nothing on this page should delay you from contacting a qualified healthcare professional about your kidney health.
- To report a suspected error in this tool, contact the site publisher, Clinical Tools Library. To report an adverse event related to a medical device or medication, use the relevant national reporting system (for example, FDA MedWatch at fda.gov/medwatch in the United States).
CKD stages by eGFR
| Stage | eGFR (mL/min/1.73m²) | General meaning |
|---|---|---|
| 1 | 90 or above | Normal or high function, with other evidence of kidney damage |
| 2 | 60–89 | Mild loss of kidney function |
| 3a | 45–59 | Mild-to-moderate loss |
| 3b | 30–44 | Moderate-to-severe loss |
| 4 | 15–29 | Severe loss of kidney function |
| 5 | Below 15 | Kidney failure; dialysis or transplant usually needed |
Average eGFR by age
| Age (years) | Average eGFR |
|---|---|
| 20–29 | 116 |
| 30–39 | 107 |
| 40–49 | 99 |
| 50–59 | 93 |
| 60–69 | 85 |
| 70+ | 75 |
Formulas used
eGFRcr = 142 × min(Scr/κ,1)^α × max(Scr/κ,1)^-1.200 × 0.9938^Age × (1.012 if female)
eGFRcr-cys = 135 × min(Scr/κ,1)^α × max(Scr/κ,1)^-0.544 × min(Scys/0.8,1)^-0.323 × max(Scys/0.8,1)^-0.778 × 0.9961^Age × (0.963 if female)
κ = 0.7 (female) or 0.9 (male). α = -0.241 (female) / -0.302 (male) for the creatinine equation, or -0.219 (female) / -0.144 (male) for the combined equation. Both equations are race-free, per the 2021 NKF-ASN Task Force recommendation.
This calculator applies to adults aged 18 and over. For children and young adults up to age 25, NIDDK's CKiD U25 and Schwartz "bedside" equations apply instead — this tool does not compute those.
Sources
- Inker LA, Eneanya ND, Coresh J, et al. New Creatinine- and Cystatin C-Based Equations to Estimate GFR without Race. N Engl J Med. 2021;385(19):1737-1749.
- NIDDK — eGFR Equations for Adults
- National Kidney Foundation — CKD-EPI Creatinine Equation (2021)
- National Kidney Foundation — CKD-EPI Creatinine-Cystatin Equation (2021)
- National Kidney Foundation — Estimated GFR (eGFR) Test (average-by-age reference data)
Last reviewed: July 2026 — Clinical Tools Library.
eGFR Calculator — Summary
Educational reference only, not medical advice. CKD-EPI 2021 equation(s). Generated by Clinical Tools Library — clinicaltoolslibrary.com. Last reviewed July 2026.
What Is the DaVita GFR Calculator?
A DaVita GFR calculator estimates your glomerular filtration rate — the rate at which your kidneys filter blood — from routine lab values such as serum creatinine, age, and sex. GFR is widely considered the best overall measure of kidney function, and an estimated GFR under 60 mL/min/1.73m² that persists for three months or longer is one of the defining markers of chronic kidney disease. Because a true “measured” GFR requires a specialized clearance test that’s rarely performed outside research settings, clinicians almost always work from an estimated GFR (eGFR) instead — which is exactly what this calculator, and the CKD-EPI equation behind it, is designed to approximate.
How the DaVita GFR Calculator Works: The CKD-EPI Formula
This calculator uses the 2021 CKD-EPI creatinine equation, the race-free formula recommended by the National Kidney Foundation–American Society of Nephrology Task Force and supported by the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) for estimating GFR in adults. The equation combines a handful of everyday lab and demographic inputs into a single eGFR value expressed in mL/min/1.73m².
What You’ll Need to Enter
Serum creatinine from a recent blood draw, your age, and your biological sex are the core inputs the CKD-EPI equation needs. Some versions of the DaVita GFR calculator also request height and weight so the result can be cross-checked, though the eGFR figure itself is driven mainly by creatinine, age, and sex. If you’d rather work from a measured creatinine clearance instead of an estimating equation, our creatinine clearance calculator uses the Cockcroft-Gault method as an alternative.
Understanding the CKD-EPI 2021 Equation
The CKD-EPI equation applies different coefficients depending on your sex and how your creatinine compares to a reference value, then adjusts for age. The result is standardized to a body surface area of 1.73m², which is roughly average for an adult, so eGFR values are comparable across different body sizes. Because estimating equations become less precise at higher eGFR values, and because pregnancy, unusual muscle mass, or a recent change in kidney function can skew results, your care team may sometimes order a cystatin C test or a directly measured GFR to confirm a borderline number.
GFR Ranges, CKD Stages, and What They Mean
Once you have an eGFR number, the next question is what it means for your kidney health. Kidney function is generally grouped into five stages, and where you fall helps guide monitoring, diet, and treatment decisions alongside your full CKD stages guide.
Average GFR by Age
| Age (years) | Average eGFR (mL/min/1.73m²) |
|---|---|
| 20–29 | 116 |
| 30–39 | 107 |
| 40–49 | 99 |
| 50–59 | 93 |
| 60–69 | 85 |
| 70+ | 75 |
eGFR naturally declines with age even in people without kidney disease, which is one reason the CKD-EPI equation factors in age at all. At any age, though, an eGFR that stays below 60 mL/min/1.73m² for three months or more is considered a sign of reduced kidney function worth discussing with a doctor, according to the National Kidney Foundation.
The Five Stages of Chronic Kidney Disease
| Stage | eGFR (mL/min/1.73m²) | General meaning |
|---|---|---|
| 1 | 90 or above | Normal or high function, with other signs of kidney damage |
| 2 | 60–89 | Mild loss of kidney function |
| 3a | 45–59 | Mild-to-moderate loss |
| 3b | 30–44 | Moderate-to-severe loss |
| 4 | 15–29 | Severe loss of kidney function |
| 5 | Below 15 | Kidney failure; dialysis or transplant usually needed |
GFR, Dialysis, and When to See a Nephrologist
A single low reading on a DaVita GFR calculator isn’t a diagnosis — eGFR can dip temporarily from dehydration, illness, or certain medications. But a consistently low eGFR, especially alongside protein in the urine, is a reason to see a nephrologist (kidney specialist), as outlined by the CDC’s chronic kidney disease guidance. Most people don’t need dialysis until eGFR falls into Stage 4 or Stage 5, and even then, treatment planning — including whether home dialysis, in-center dialysis, or a transplant makes sense — typically starts well before kidney failure, giving you and your care team time to prepare. You can also explore your broader risk with our standalone eGFR calculator, which walks through each input step by step.
Frequently Asked Questions
What is a good GFR number?
A GFR of 90 or above is generally considered normal in adults with no other signs of kidney damage. Because GFR declines gradually with age, a lower number in an older adult doesn’t automatically indicate disease — your doctor looks at the trend over time, not just one reading.
What information does the DaVita GFR calculator use?
It estimates GFR from serum creatinine along with your age and sex, using the CKD-EPI equation. Some versions also ask for height and weight. It doesn’t require a urine sample, though your doctor may separately order a urine albumin-to-creatinine ratio test for a fuller picture, per MedlinePlus.
What is the average GFR by age?
Average eGFR is roughly 116 for people in their 20s and declines to around 75 by age 70 and older, based on National Kidney Foundation reference data. A below-average number for your age group isn’t automatically abnormal, but a value under 60 sustained for three months or more warrants follow-up.
Does a low GFR always mean I need dialysis?
No. Dialysis is typically considered only in Stage 5 CKD (eGFR below 15) or when symptoms of kidney failure appear, and many people with Stage 3 or even Stage 4 CKD are managed for years with diet, medication, and monitoring alone. Your nephrologist bases any dialysis decision on your full clinical picture, not a single eGFR number.
Is a DaVita GFR calculator result the same as a lab report?
Not exactly. An online GFR calculator applies the CKD-EPI formula to values you enter yourself, so it’s only as accurate as the numbers you input and doesn’t replace a lab-verified eGFR ordered by your doctor. You can compare your result with DaVita’s own GFR calculator tool, then confirm any concerning result with an actual blood test.
