GFR Calculator – Estimate Glomerular Filtration Rate (eGFR) Online

Use this free GFR calculator to quickly estimate your glomerular filtration rate (eGFR), a key measure of kidney function. Enter your serum creatinine, age, sex, and race to get an instant result in mL/min/1.73 m².

What is GFR (eGFR)?

Glomerular filtration rate (GFR) describes how well your kidneys filter blood. Because direct measurement is complex, healthcare providers usually use an estimated GFR (eGFR) based on blood creatinine, age, sex, and race.

eGFR is used to:

• Screen for chronic kidney disease (CKD)
• Stage the severity of kidney impairment
• Monitor progression of kidney disease over time
• Adjust medication doses that depend on kidney function

How to use this GFR calculator

This tool is designed to be simple and fast:

• Choose the formula if available (e.g., CKD-EPI or MDRD, depending on the implementation).
• Enter your serum creatinine value in the supported units (µmol/L or mg/dL).
• Provide your age, sex, and race when requested.
• Click the calculate button to see your estimated GFR in mL/min/1.73 m².

The result is for informational and educational purposes only and does not replace professional medical advice, diagnosis, or treatment.

Understanding your GFR result

Typical eGFR categories used in chronic kidney disease staging include:

• G1: eGFR ≥ 90 mL/min/1.73 m² – normal or high (with other evidence of kidney damage if CKD is present)
• G2: eGFR 60–89 – mildly decreased
• G3a: eGFR 45–59 – mildly to moderately decreased
• G3b: eGFR 30–44 – moderately to severely decreased
• G4: eGFR 15–29 – severely decreased
• G5: eGFR < 15 – kidney failure

Only a qualified healthcare professional can interpret these values in the context of your overall health, lab results, and symptoms.

Why use the urwatools GFR calculator?

• Fast and clean: Lightweight tool focused on speed and clarity.
• Privacy-first: Inputs are processed only to generate the result; no unnecessary tracking or data storage.
• No login required: Use the eGFR calculator instantly from any device.
• Clear output: Easy-to-read estimated GFR value with basic interpretation guidance.

Common uses of an eGFR calculator

• Checking kidney function when you have a recent serum creatinine result.
• Tracking estimated kidney function over time with your lab reports.
• Preparing for a medical appointment with your doctor or nephrologist.
• Educational use for students and healthcare professionals learning about renal function.

Limitations of GFR estimation

eGFR calculators use standardized equations such as MDRD or CKD-EPI. These formulas have limitations and may be less accurate in:

• Very muscular or very thin individuals
• Pregnancy
• Extremes of age (very young or very old)
• Severe liver disease or unusual diets

Always discuss any concerns about kidney function with your healthcare provider.

FAQ about GFR and this calculator

Is this GFR calculator accurate?

The calculator uses widely accepted estimating equations for eGFR. However, no online tool can guarantee clinical accuracy. Use it as a guide and confirm results with a medical professional.

Do you store my health data?

No. urwatools is designed to be privacy-focused. Your entries are used only to compute the result and are not stored for tracking or marketing.

Can this tool diagnose kidney disease?

No. This GFR calculator is for informational purposes only and cannot provide a diagnosis. Diagnosis and treatment decisions must be made by a licensed healthcare professional.

What units of creatinine can I use?

Most GFR calculators accept creatinine in mg/dL or µmol/L. Check the input labels in this tool and match them to your lab report.

How often should I check my eGFR?

The appropriate testing frequency depends on your risk factors and existing conditions. Follow the schedule recommended by your doctor.