Free eGFR Calculator (2026)
Estimate Kidney Function Online
Enter your serum creatinine, age and sex to instantly estimate your kidney function (eGFR), know your CKD stage, and understand what your result means for your health and dialysis planning.
🧮 eGFR Calculator
Uses CKD-EPI 2021 (recommended, race-free) · CKD-EPI 2009 · MDRD
📊 CKD Stages — eGFR Reference Chart
| Stage | eGFR (mL/min) | What It Means | Dialysis |
|---|---|---|---|
| G1 | ≥ 90 | Normal or high — monitor if kidney damage present | No |
| G2 | 60 – 89 | Mildly decreased — usually no symptoms, lifestyle changes | No |
| G3a | 45 – 59 | Mild-to-moderate — nephrologist review recommended | No |
| G3b | 30 – 44 | Moderate-to-severe — close monitoring essential | Planning |
| G4 | 15 – 29 | Severely decreased — dialysis or transplant planning | Prepare |
| G5 | < 15 | Kidney failure — dialysis or transplant typically needed | Urgent |
🔬 What Is eGFR?
eGFR stands for estimated Glomerular Filtration Rate. It is the most widely used measure of kidney function. It estimates how many millilitres of blood your kidneys filter per minute per 1.73 square metres of body surface area.
Your kidneys contain about one million tiny filters called glomeruli. As kidney function declines — due to diabetes, high blood pressure, or other conditions — the GFR falls. A healthy adult typically has an eGFR above 90 mL/min/1.73m².
Why Do Doctors Order an eGFR Test?
✔ To detect kidney disease early — often before symptoms appear
✔ To monitor progression of known CKD (Chronic Kidney Disease)
✔ To determine the right dose of medicines cleared by kidneys
✔ To plan for dialysis or kidney transplant in advanced stages
✔ To evaluate kidney function before surgery or contrast imaging
📐 How Is eGFR Calculated?
eGFR is calculated from a simple blood test for serum creatinine, combined with your age and sex. The most accurate formula currently recommended is the CKD-EPI 2021 equation — which was developed by the National Kidney Foundation (NKF) and the American Society of Nephrology (ASN).
Serum Creatinine
Waste product from muscle metabolism — rises when kidneys filter less effectively
Age
eGFR naturally decreases with age even in healthy kidneys
Sex
Females typically have lower creatinine than males — adjusted in formula
CKD-EPI Equation
The gold-standard formula since 2021 — removes race as a variable
⚖️ CKD-EPI vs MDRD — Which Formula Is Better?
| Formula | Year | Recommended | Race Variable | Accuracy | Best For |
|---|---|---|---|---|---|
| CKD-EPI 2021 | 2021 | ✅ Yes — Current Standard | ❌ No (removed) | ⭐⭐⭐⭐⭐ | All patients globally |
| CKD-EPI 2009 | 2009 | ⚠️ Older | ✅ Yes (Black/non-Black) | ⭐⭐⭐⭐ | Legacy use |
| MDRD 4-variable | 1999 | ❌ Not preferred | ✅ Yes | ⭐⭐⭐ | Historical research |
🔄 eGFR vs Serum Creatinine — What’s the Difference?
| Feature | Serum Creatinine | eGFR |
|---|---|---|
| What it measures | Waste product in blood | Estimated kidney filtration rate |
| Affected by muscle mass | Yes — higher in muscular people | Adjusts for age and sex |
| Changes with age | Not directly | Yes — naturally decreases |
| Better for CKD diagnosis | ❌ Less accurate alone | ✅ Gold standard |
| Normal range (adult) | 0.6–1.2 mg/dL (varies) | ≥ 60 mL/min/1.73m² |
| Rises when kidneys fail | Yes | eGFR falls |
⚠️ What Causes a Low eGFR?
A low eGFR can result from many different conditions — some temporary, some permanent. Here are the most common causes:
Diabetes
Diabetic nephropathy — the leading cause of CKD globally. High sugar damages kidney filters
High Blood Pressure
Hypertensive nephropathy — damages kidney blood vessels over time
Glomerulonephritis
Inflammation of the kidney’s filtering units — can be sudden or chronic
Kidney Stones
Repeated stones can damage kidney tissue and obstruct urine flow
Painkiller Overuse
NSAIDs (ibuprofen, diclofenac) reduce blood flow to kidneys long-term
Polycystic Kidney Disease
Inherited condition causing cysts that gradually destroy kidney tissue
Kidney Infections
Recurrent pyelonephritis or chronic UTIs can scar kidney tissue
Dehydration
Severe dehydration reduces kidney blood flow and can acutely lower eGFR
Aging
eGFR naturally declines by ~1 mL/min per year after age 40 — even without disease
Heart Failure
Reduced cardiac output reduces kidney blood flow (cardiorenal syndrome)
🩺 Symptoms of Kidney Disease (CKD)
Early CKD often has no symptoms at all — which is why eGFR testing is critical. Symptoms typically appear only in Stages G3b–G5.
Swelling
Fluid retention in legs, ankles, and feet — often worsens by evening
Fatigue
Persistent tiredness and weakness — due to anaemia and toxin buildup
Foamy Urine
Persistent foam indicates protein in urine — an early warning sign
Blood in Urine
Pink, red, or brown urine — needs urgent evaluation
Loss of Appetite
Nausea, metallic taste, poor appetite — common in advanced CKD
Nausea & Vomiting
Toxin buildup (uraemia) causes persistent nausea in late CKD
Itching
Phosphorus buildup causes severe skin itching in G4–G5
Shortness of Breath
Fluid in lungs or anaemia causes breathlessness — can be severe
👨⚕️ When Should You See a Nephrologist?
Many patients delay seeking specialist care until CKD is advanced. KDIGO guidelines recommend nephrologist referral earlier than most patients expect:
💪 Can Low eGFR Improve?
This is one of the most searched questions by patients. The honest answer: it depends entirely on the cause.
Can Improve
Dehydration, acute kidney injury, drug-induced damage, urinary obstruction, controlled BP and sugar
May Stabilise
Early to moderate CKD from diabetes or hypertension — eGFR can plateau with treatment
Usually Progressive
Advanced CKD (G4–G5), polycystic kidney disease, scarred kidneys — slowing is the realistic goal
🌱 How to Improve Kidney Health
🥗 Foods for Kidney Health
Diet plays a major role in protecting kidney function and slowing CKD. A kidney dietitian can create a personalised plan based on your stage.
Cauliflower & Cabbage
Low-potassium vegetables — safe at most CKD stages
Apples & Berries
Low-potassium fruits with antioxidants — protective for kidney cells
Omega-3 Fish
Salmon, mackerel — anti-inflammatory, heart and kidney protective
Onions & Garlic
Natural flavour without potassium/phosphorus overload
Egg Whites
High-quality protein with less phosphorus than egg yolk
Reduce Salt
Limit to 2g sodium/day — avoid processed foods, pickles, papad
Adequate Water
Unless restricted — helps flush waste without overloading kidneys
Avoid: Bananas, Potatoes
High-potassium foods — limit in G3b+ to avoid hyperkalaemia
🔬 Additional Kidney Tests You May Need
eGFR is the starting point — but a complete kidney assessment includes several other investigations:
🩸 Serum Creatinine
The raw value used to calculate eGFR. Rises when kidneys fail.
💧 Urine ACR
Albumin-to-Creatinine Ratio — detects protein leak. Critical for early CKD diagnosis.
🧪 Urine Routine & Microscopy
Checks for blood, protein, casts, infection in urine.
📷 Kidney Ultrasound
Shows kidney size, cysts, stones, obstruction, scarring.
🧬 BUN (Blood Urea Nitrogen)
Another waste marker — used alongside creatinine to assess kidney clearance.
⚡ Electrolytes
Sodium, potassium, bicarbonate — kidney regulates these. Abnormal in CKD.
🩺 HbA1c
3-month blood sugar average — essential in diabetic kidney disease.
❤️ Blood Pressure
Monitor at every visit — target below 130/80 in CKD patients.
❓ Frequently Asked Questions — eGFR & Kidney Disease
Is eGFR 60 normal?
An eGFR of exactly 60 is at the threshold. An eGFR between 60–89 (Stage G2) is considered mildly decreased. If eGFR stays below 60 on two tests 3 months apart — this meets the definition of CKD (Stage G3a or lower). An isolated eGFR of 60 with no protein in urine and no kidney damage is not necessarily a cause for alarm, but should be monitored annually.
Can a low eGFR improve on its own?
Sometimes yes — especially if the cause is temporary (dehydration, acute illness, certain medicines). In established CKD due to diabetes or hypertension, the goal is usually stabilisation rather than reversal. However, treating the underlying cause aggressively can slow or stop progression, and in some cases eGFR does improve. A nephrologist evaluation is essential to determine what’s possible in your specific case.
Can dehydration lower eGFR?
Yes. Dehydration reduces blood flow to the kidneys, which temporarily reduces the filtration rate. This is called “pre-renal” acute kidney injury. Drinking adequate water and correcting dehydration typically restores eGFR. This is why a repeat test after rehydration is often ordered before diagnosing CKD.
Is dialysis needed if eGFR is 20?
Not immediately — but preparation should begin. An eGFR of 20 is Stage G4 (severely decreased). Dialysis is typically initiated when eGFR falls to 10–15 (Stage G5). However, creating an AV fistula (the access used for haemodialysis) takes 3–6 months to mature — so planning must begin at Stage G4. Your nephrologist will determine the right timing.
Does age affect eGFR?
Yes, significantly. eGFR naturally declines with age at approximately 1 mL/min per year after age 40 — even in healthy individuals without kidney disease. A 75-year-old with an eGFR of 65 may have perfectly normal kidney function for their age. This is why age is included in the eGFR calculation formula.
Is eGFR 30 dangerous?
eGFR 30 is Stage G3b — moderate to severe kidney disease. At this level, dialysis planning should be discussed, AV fistula creation should be considered, and very close nephrologist monitoring (every 3 months) is essential. It is serious but not immediately life-threatening if managed properly. Contact a nephrologist without delay.
Does diabetes reduce eGFR?
Yes. Diabetic nephropathy is the most common cause of CKD worldwide. High blood sugar damages the glomeruli (kidney filters) over years. It typically begins with protein appearing in urine (microalbuminuria), followed by gradual eGFR decline. Tight blood sugar control (HbA1c below 7%) and kidney-protective medicines (ACE inhibitors, SGLT2 inhibitors) can slow this significantly.
Can exercise change creatinine levels?
Yes. Intense exercise causes muscle breakdown which temporarily releases creatinine into the blood, raising serum creatinine and lowering calculated eGFR temporarily. This is why kidney tests should ideally be done at rest, not immediately after strenuous exercise. Moderate regular exercise is actually beneficial for kidney health long-term.
Which doctor treats low eGFR?
A nephrologist (kidney specialist) is the primary doctor for managing CKD and low eGFR. At early stages (G1–G2), your GP or general physician may manage it. From G3 onwards, nephrologist involvement is strongly recommended by KDIGO guidelines. Doctor Visit Bangalore can connect you with an experienced nephrologist in Bangalore — WhatsApp +91 78920 28951.
How often should eGFR be checked?
KDIGO 2024 recommends: G1–G2 (if stable): Once yearly. G3a–G3b: Every 6 months. G4: Every 3 months. G5: Every 1–3 months. Patients with diabetes, hypertension, or rapidly declining eGFR should check more frequently. Ask your doctor for personalised advice.
Is one abnormal eGFR result enough to diagnose CKD?
No. CKD is defined as kidney damage or eGFR below 60 present for more than 3 months. A single low eGFR result could be due to temporary causes (dehydration, illness, medicine, recent intense exercise). Two or more low eGFR readings taken at least 3 months apart — or evidence of kidney damage (protein in urine, abnormal ultrasound) — are needed to confirm CKD.
Which foods help kidney function?
Kidney-protective foods include: cauliflower, cabbage, apples, berries, egg whites, omega-3 fish (salmon, mackerel), onions, garlic, and adequate water intake. Foods to limit in CKD include: high-potassium foods (bananas, potatoes, oranges), high-phosphorus foods (dairy, nuts, processed foods), and excessive protein and salt. A kidney dietitian can create a personalised plan based on your CKD stage and blood results.
🔗 Related Health Calculators & Guides
✅ Why Trust This Calculator?
Evidence-Based Formulas
CKD-EPI 2021 — endorsed by NKF, KDIGO, WHO and NICE
Last Updated July 2026
Reviewed against current KDIGO 2024 guidelines
100% Free Tool
No sign-up, no data stored, no advertising
Clinically Validated
Used by nephrologists and labs worldwide
📚 References & Guidelines
- 1Kidney Disease: Improving Global Outcomes (KDIGO) CKD Work Group. KDIGO 2024 Clinical Practice Guideline for the Evaluation and Management of Chronic Kidney Disease. Kidney Int. 2024.
- 2Inker LA, Eneanya ND, et al. New Creatinine- and Cystatin C–Based Equations to Estimate GFR without Race. New England Journal of Medicine. 2021;385:1737–1749. (CKD-EPI 2021)
- 3National Kidney Foundation. KDOQI Clinical Practice Guideline for Diabetes and CKD: 2022 Update. Am J Kidney Dis. 2022.
- 4American Kidney Fund. eGFR and Kidney Function. www.kidneyfund.org. Accessed July 2026.
- 5National Institute for Health and Care Excellence (NICE). Chronic kidney disease: assessment and management. NICE guideline NG203. Updated 2021.
- 6Centers for Disease Control and Prevention (CDC). Chronic Kidney Disease in the United States, 2023. US Department of Health and Human Services.
⚠️ This calculator is for informational and educational purposes only. eGFR is an estimate — actual kidney function should always be interpreted by a qualified nephrologist using your complete clinical picture, urine albumin-to-creatinine ratio, imaging, and symptoms. A single eGFR value is not sufficient to diagnose CKD. CKD requires eGFR below 60 or evidence of kidney damage persisting for more than 3 months. Do not make treatment, dialysis, or medication decisions based on this calculator alone.
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