What this GFR Calculator does
This English-language eGFR estimator calculates your glomerular filtration rate from serum creatinine, age, sex, and race using the two most widely used equations — CKD-EPI (2021) and MDRD. The result tells you how well your kidneys are filtering waste from your blood, expressed in mL/min/1.73 m². Normal range is generally ≥60 mL/min/1.73 m², and values below that threshold correspond to the chronic kidney disease staging system recognized by WHO BMI classification and nephrology guidelines alike. If you're also tracking body composition, the [BMI calculator](/en/bmi-calculator/) on this site handles that in one step. 100% client-side — your data never leaves your browser. No uploads, no tracking, no server logs.
Features
- Dual-equation output. Runs both CKD-EPI (2021, race-free) and MDRD simultaneously so you can compare results side by side.
- CKD stage labeling. Maps your eGFR estimate to a CKD stage (G1–G5) automatically, including the normal ≥90 range.
- Creatinine unit toggle. Switch between mg/dL (U.S. standard) and µmol/L without re-entering your values.
- Instant GFR clearance calculation. No server round-trip. The glomerular filtration calc runs entirely in JavaScript the moment you hit Calculate.
- Privacy by design. Serum creatinine and patient demographics never leave your device. No account, no cookies, no logs — the MDN — crypto.getRandomValues API is the only browser feature we rely on for entropy, and even that is optional.
- Copy-ready result. One click copies the formatted eGFR result and stage label so you can paste it directly into a clinical note or spreadsheet.
How to use the GFR Calculator
Enter your serum creatinine value, age, sex, and (for MDRD) race, then click Calculate. Results appear immediately below.
- Enter serum creatinine. Type your lab result — e.g.
1.1 mg/dL— and choose mg/dL or µmol/L from the unit toggle. - Fill in demographics. Enter your age in years and select your biological sex. Both CKD-EPI and MDRD equations use these inputs.
- Click Calculate. The eGFR estimator returns both CKD-EPI and MDRD values in mL/min/1.73 m², plus the corresponding CKD stage.
- Review and copy. Read the stage label and normal-range note. Hit Copy to grab the result for a report or EHR paste.
Common use cases
- Pre-appointment review. Patients in Seattle or Toronto who receive a creatinine lab result before their nephrology visit can compute their eGFR and understand their CKD stage before the appointment.
- Medication dosing reference. Pharmacists and prescribers routinely need a quick glomerular filtration rate calculator to check whether a drug dose must be adjusted for renal function — without logging into a full clinical system.
- Nursing and PA students. Students learning renal physiology can compute GFR estimates for practice cases and verify their manual calculations against both CKD-EPI and MDRD outputs.
- Chronic disease self-monitoring. People managing diabetes or hypertension — two leading causes of CKD — can track eGFR trends over successive lab draws alongside other metrics. Pairing this tool with the [TDEE calculator](/en/tdee-calculator/) gives a fuller metabolic picture.
- Research and teaching. Researchers comparing CKD-EPI vs. MDRD classification discordance in a cohort can use this estimator to quickly spot-check individual cases without writing a new script.
Frequently asked questions
What is a normal eGFR range?
An estimated glomerular filtration rate of 60 mL/min/1.73 m² or higher is generally considered within normal limits for adults. Values of 90 and above (Stage G1) indicate normal or high function. Stages G3a through G5 (eGFR below 60 down to near zero) correspond to progressively reduced kidney function and are used to guide clinical decisions.
What's the difference between CKD-EPI and MDRD?
MDRD (Modification of Diet in Renal Disease) was the dominant equation for decades and included a race coefficient. CKD-EPI (Chronic Kidney Disease Epidemiology Collaboration), updated in 2021 to remove the race variable, is now recommended by most nephrology societies because it performs better across a wider eGFR range, particularly for values above 60 mL/min/1.73 m².
Is my data private when I use this calculator?
Yes. This is a 100% client-side tool. Your serum creatinine value, age, sex, and any other inputs are processed entirely inside your browser using JavaScript. Nothing is transmitted to a server, stored in a database, or used for tracking. You can even disconnect from the internet after the page loads and the calculator will still work.
Can I use this eGFR estimate as a medical diagnosis?
No. This tool provides an educational eGFR estimation only. The equations it uses are the same ones in clinical use, but a formal diagnosis of CKD requires interpretation by a qualified clinician who can review your full history, repeated measurements, and other biomarkers like urine albumin-to-creatinine ratio. Use this as a starting point for an informed conversation with your doctor, not as a standalone verdict.
Why does my eGFR look lower on MDRD than on CKD-EPI?
MDRD tends to underestimate GFR at higher function levels (above ~60 mL/min/1.73 m²). If your creatinine is near normal, CKD-EPI typically gives a more accurate estimate. For lower function values, the two equations tend to converge. This is one reason CKD-EPI replaced MDRD as the preferred equation in most laboratory reference ranges.
How is GFR different from creatinine clearance?
Creatinine clearance (measured via a 24-hour urine collection) is a direct measurement, while eGFR is an estimate derived from serum creatinine alone using a population-derived equation. eGFR is more convenient and is the standard in routine clinical chemistry panels. Measured creatinine clearance is sometimes ordered when high precision is needed, such as before certain chemotherapy regimens.