Calculate Your Kidney Function Instantly
Use our free online eGFR calculator powered by the CKD-EPI 2021 equation. Get accurate kidney function estimates in seconds with our easy-to-use tool.
Instant Results
Get your eGFR value in seconds
CKD-EPI 2021
Latest recommended formula
100% Free
No registration required
Free Online eGFR Calculator
Calculate your estimated Glomerular Filtration Rate using the latest CKD-EPI 2021 race-free equations. Supports creatinine-only, cystatin C-only, and combined calculations.
Enter Your Values
Fill in the form on the left and click "Calculate eGFR" to see your results here.
Kidney Disease Risk Calculator
Assess your risk factors for chronic kidney disease and get personalized recommendations
Recommendation
Continue maintaining a healthy lifestyle and get kidney function tested as part of routine checkups.
Understanding eGFR: Your Complete Guide
Learn everything about the estimated Glomerular Filtration Rate (eGFR) and how our free online eGFR calculator can help you monitor kidney health.
The Gold Standard for Kidney Function Assessment
The estimated Glomerular Filtration Rate (eGFR) is the best overall indicator of kidney function. It measures how well your kidneys filter waste and excess fluids from your blood. Our free online eGFR calculator uses the latest CKD-EPI 2021 equation recommended by the National Kidney Foundation and the American Society of Nephrology.
The GFR represents the volume of blood filtered by the glomeruli (tiny filters in your kidneys) per minute. A normal eGFR is typically 90 mL/min/1.73m² or higher, though it naturally decreases with age. Using our free eGFR calculator online, you can quickly estimate your kidney function with just a few simple inputs.
Healthcare professionals worldwide rely on eGFR calculations to screen for chronic kidney disease (CKD), monitor kidney function over time, adjust medication dosages, and make important treatment decisions. Our kidney function calculator provides the same accuracy used in clinical settings.
The Latest Recommended eGFR Calculation Method
Our free online GFR calculator uses the CKD-EPI Creatinine Equation (2021), which represents the most current and accurate method for estimating kidney function. This equation was developed by the Chronic Kidney Disease Epidemiology Collaboration and has been endorsed by major nephrology organizations worldwide.
The 2021 update removed race as a variable in the calculation, making the eGFR estimation more equitable and clinically appropriate. This change was recommended by the joint National Kidney Foundation (NKF) and American Society of Nephrology (ASN) Task Force. Our kidney GFR calculator implements this latest standard.
The formula calculates eGFR based on serum creatinine level, age, and sex. Creatinine is a waste product from normal muscle metabolism, and its blood level indicates how effectively your kidneys are filtering. Use our creatinine to GFR calculator for quick and accurate results.
Chronic Kidney Disease Classification
Chronic Kidney Disease is classified into five stages based on eGFR values. Our free online kidney function test calculator helps you understand where you stand.
≥90
Normal or high kidney function
60-89
Mildly decreased function
45-59
Mild to moderate decrease
30-44
Moderate to severe decrease
<30
Severe decrease or failure
Using Our Free Online eGFR Calculator
Our free eGFR calculator online is designed to be simple and user-friendly. Follow these easy steps to calculate your estimated kidney function:
- 1Enter your serum creatinine value from your blood test results. You can input the value in either mg/dL or µmol/L units.
- 2Enter your age in years. The eGFR calculator is designed for adults aged 18 years and older.
- 3Select your sex (male or female) as this affects the calculation according to the CKD-EPI formula.
- 4Click "Calculate eGFR" to instantly receive your estimated GFR value and corresponding CKD stage.
The Importance of Monitoring Your eGFR
Early Detection
Regular eGFR monitoring helps detect kidney problems early, when treatment is most effective. Our free kidney function calculator makes screening accessible to everyone.
Track Progress
Monitor changes in kidney function over time. Use our GFR calculator online free to track your results and share them with your healthcare provider.
Medication Safety
Many medications require dose adjustments based on kidney function. Knowing your eGFR helps ensure safe and effective medication dosing.
Risk Assessment
eGFR helps assess cardiovascular risk and overall health status. Low kidney function is associated with increased risk of heart disease and other conditions.
Treatment Planning
Healthcare providers use eGFR to plan treatments and interventions. Early intervention can slow the progression of kidney disease significantly.
Lifestyle Guidance
Understanding your kidney function helps guide dietary and lifestyle choices that can protect and even improve your kidney health over time.
Risk Factors for Kidney Disease
Understanding risk factors helps you take proactive steps to protect your kidney health. If you have any of these risk factors, regular monitoring with our free online eGFR calculator is especially important.
- Diabetes (type 1 or type 2)
- High blood pressure (hypertension)
- Heart disease or family history of heart disease
- Obesity or being overweight
- Family history of kidney disease
- Age 60 years or older
- Prolonged use of NSAIDs or certain medications
- Smoking
- African, Hispanic, Asian, or Native American heritage
Why Choose Our Free eGFR Calculator?
Free to use, no registration required
Latest CKD-EPI equation standard
Instant calculation results
Available anytime, anywhere online
Drug Dosing Adjustments Based on eGFR
Many medications require dose adjustments in patients with reduced kidney function. This guide provides general recommendations.
| Medication | Normal (eGFR ≥60) | Mild (eGFR 45-59) | Moderate (eGFR 30-44) | Severe (eGFR <30) |
|---|---|---|---|---|
| Metformin | 500-2000 mg/day | 500-2000 mg/day | Avoid or reduce dose | Contraindicated |
| Gabapentin | 300-1200 mg TID | 200-700 mg BID | 200-700 mg daily | 100-300 mg daily |
| Enoxaparin | 1 mg/kg BID | 1 mg/kg daily | 0.5-1 mg/kg daily | Avoid |
| Digoxin | 0.125-0.25 mg daily | 0.0625-0.125 mg daily | 0.0625 mg daily | Reduce dose or avoid |
| Acyclovir | 400-800 mg 5x/day | 400-800 mg TID | 400-800 mg BID | 400-800 mg daily |
- • Start with lower doses in patients with reduced kidney function
- • Monitor for drug toxicity more frequently
- • Avoid nephrotoxic drugs when possible
- • Consider extended dosing intervals
- • Regular monitoring of kidney function is essential
- • NSAIDs (ibuprofen, naproxen) in advanced CKD
- • Certain antibiotics (aminoglycosides)
- • Metformin in severe CKD (eGFR <30)
- • Some contrast dyes
- • Consult with nephrologist for alternatives
Nutrition Guide for Kidney Health
Proper nutrition plays a crucial role in managing kidney disease and maintaining optimal kidney function
Cauliflower
Low in potassium and phosphorus
Berries
Rich in antioxidants, low in potassium
Fish
High-quality protein, omega-3 fatty acids
Egg whites
Phosphorus-free protein source
Cabbage
Kidney-friendly vegetable
Red bell peppers
Low potassium, high in vitamins
Dark-colored colas
High in phosphorus additives
Bananas and oranges
High in potassium
Processed meats
High in sodium and phosphorus
Whole wheat bread
High in phosphorus and potassium
Canned foods
High sodium content
Pickles and olives
Very high in sodium
Moderate protein intake (0.6-0.8 g/kg/day) in CKD stages 3-5. Choose high-quality protein sources and consult a dietitian.
Limit sodium to less than 2,300 mg per day. Avoid adding salt to food and choose fresh over processed foods.
Fluid restrictions may be necessary in advanced CKD. Monitor daily weight and follow your healthcare provider's guidance.
Other Kidney Function Calculators
Explore additional tools to assess kidney function and related clinical parameters
CrCl = [(140 - Age) × Weight × (0.85 if female)] / (72 × SCr)
FENa = [(UNa × PCr) / (PNa × UCr)] × 100
Based on multiple clinical variables and biomarkers
Frequently Asked Questions
Everything you need to know about our free online eGFR calculator and kidney function testing.