eGFR (estimated glomerular filtration rate) measures how well your kidneys filter waste from the blood. Expressed in mL/min/1.73m², it is the primary metric for diagnosing and staging chronic kidney disease. An eGFR ≥90 with no kidney damage markers is normal.

What is the CKD-EPI 2021 equation?

The CKD-EPI 2021 equation is the current standard for eGFR calculation, recommended by KDIGO, NKF, and ASN. It removed the race coefficient from the 2009 version after a joint task force determined race-based adjustments were scientifically unjustified. It uses creatinine, age, and sex.

What do the CKD stages mean?

CKD stages: G1 (eGFR ≥90, normal), G2 (60–89, mildly decreased), G3a (45–59, mild-moderate), G3b (30–44, moderate-severe), G4 (15–29, severe), G5 (<15, kidney failure). Stages G1–G2 require other damage markers to diagnose CKD. G3–G5 are diagnosed by eGFR alone.

How often should eGFR be checked?

Healthy adults: every 1–2 years as part of routine blood work. Diabetes or hypertension: annually. Known CKD G3: every 3–6 months. CKD G4–G5: every 1–3 months. Rapid decliners (>5 mL/min/year) need more frequent monitoring.

What creatinine level is concerning?

Normal creatinine ranges from ~0.7–1.2 mg/dL for men and ~0.5–1.0 mg/dL for women, but these values depend on muscle mass. A creatinine of 1.5 mg/dL in a muscular 30-year-old may be normal, while the same value in a frail 80-year-old is concerning. Always interpret creatinine as eGFR.

Why was the race coefficient removed from eGFR?

The 2009 CKD-EPI equation included a coefficient that calculated higher eGFR for Black patients, based on the assumption of higher average muscle mass. A 2021 NKF-ASN task force found this approach was not scientifically rigorous and delayed CKD diagnosis and transplant referrals for Black patients.

What is the difference between eGFR and creatinine clearance?

eGFR estimates GFR from serum creatinine using equations (CKD-EPI, MDRD). [Creatinine clearance (CrCl)](/tools/creatinine-clearance) is calculated via Cockcroft-Gault and is still used for drug dosing because many older drug studies used CrCl. For clinical staging, eGFR is preferred. For dosing, check which method the drug label specifies.

Yes, especially if the decline was due to reversible factors: dehydration, medication effects, or acute illness. Even in established CKD, aggressive blood pressure control, SGLT2 inhibitors, and ACE/ARB therapy can stabilize or modestly improve eGFR. However, lost nephrons do not regenerate.

At what eGFR do I need dialysis?

Dialysis is typically started when eGFR falls below 10–15 (CKD G5) AND symptoms develop (uremia, fluid overload, hyperkalemia). The decision is based on symptoms and quality of life, not a specific eGFR cutoff. Some patients with eGFR of 8 remain asymptomatic; others need dialysis at 12.

An eGFR around 60 can be borderline and must be interpreted with context. CKD is diagnosed when eGFR remains below 60 for at least 3 months or when there are other kidney-damage markers (like albuminuria), not from a single isolated value.

Does eGFR predict life expectancy?

Lower eGFR is associated with increased cardiovascular mortality. CKD G3b–G5 patients have significantly higher risk of heart attack, stroke, and death compared to those with normal kidney function. However, many CKD patients die of cardiovascular disease before reaching dialysis.

How accurate is eGFR?

CKD-EPI 2021 estimates are within 30% of measured GFR (by iothalamate or iohexol clearance) for about 90% of patients. Accuracy decreases at extremes — very high GFR (>120), low muscle mass, or acute kidney injury. For critical decisions (transplant donor evaluation), direct GFR measurement is preferred.

Why is my eGFR high in the morning and lower at night?

Serum creatinine rises slightly after protein-rich meals and during dehydration. Morning fasting samples are most consistent. However, day-to-day eGFR variation of 5–10 mL/min is normal and should not prompt concern. Focus on trends over weeks to months.

Can supplements or creatine affect eGFR?

Yes. Creatine supplements increase serum creatinine because creatine is metabolized to creatinine. This raises measured creatinine and produces a falsely low eGFR without affecting actual kidney function. Discontinue creatine for 2–3 weeks before testing if accurate eGFR is needed.

What medications can I take to protect my kidneys?

ACE inhibitors or ARBs are first-line for CKD with proteinuria or diabetes. SGLT2 inhibitors (dapagliflozin, empagliflozin) have proven kidney-protective benefits independent of diabetes. Blood pressure control (<130/80) and avoiding NSAIDs are also essential. Discuss with your physician.

Is eGFR the same as kidney function percentage?

Loosely, yes. An eGFR of 60 is roughly 60% of normal kidney function, and eGFR 30 is about 30%. However, this is an approximation. Normal eGFR varies by age (declines ~1 mL/min/year after age 30), so an 80-year-old with eGFR 70 has age-appropriate function, not 70% of 'normal'.

Online Medical Tools — eGFR Calculator

Printed on 8/14/2026

For informational purposes only. This is not medical advice.

Clinical

eGFR Calculator

Estimated glomerular filtration rate (eGFR) is the gold standard for assessing kidney function. This calculator uses the CKD-EPI 2021 equation — the latest race-free formula recommended by KDIGO — to estimate how well your kidneys filter waste based on serum creatinine, age, and sex. Results include CKD staging from G1 (normal) to G5 (kidney failure).

Formula: CKD-EPI 2021: 142 × min(Scr/κ, 1)^α × max(Scr/κ, 1)^-1.200 × 0.9938^Age × (1.012 if female)

Sex

Age

years

Serum Creatinine

mg/dL

Creatinine Unit

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How It Works

Enter your lab values

Input your serum creatinine level from a recent blood test, along with your age and sex. Creatinine is measured in mg/dL (US) or μmol/L (international).

Calculate your eGFR

The CKD-EPI 2021 equation processes your values to estimate kidney filtration rate. Results are expressed in mL/min/1.73m², adjusted for body surface area.

Review your CKD stage

Your eGFR maps to a chronic kidney disease stage (G1–G5). See what your stage means, when to see a nephrologist, and how to protect remaining kidney function.

Who Uses the eGFR Calculator

CKD Screening

Primary care physicians

Routine screening for chronic kidney disease in patients with diabetes, hypertension, cardiovascular disease (assess with [ASCVD Risk Calculator](/tools/ascvd-risk)), or family history of kidney failure. KDIGO recommends annual eGFR for at-risk populations.

Drug Dosing Decisions

Pharmacists & prescribers

Many medications require dose adjustment based on kidney function. eGFR guides dosing for metformin, DOACs, antibiotics, and nephrotoxic drugs to prevent accumulation and toxicity. For precise drug dosing calculations, use [Creatinine Clearance](/tools/creatinine-clearance).

Disease Progression Monitoring

Nephrologists

Serial eGFR measurements track CKD progression over months to years. A decline >5 mL/min/year is considered rapid progression and may warrant intensified management.

Pre-procedure Assessment

Radiologists & surgeons

eGFR is checked before contrast-enhanced imaging to assess risk of contrast-induced nephropathy. Prophylactic hydration protocols are guided by baseline kidney function.

Transplant Evaluation

Transplant teams

eGFR helps determine when to list patients for kidney transplant (typically eGFR <20) and is used to assess donor kidney function in living donor evaluation.

Patient Self-Monitoring

CKD patients

Patients with known kidney disease can track their eGFR trend between appointments to understand disease trajectory and the impact of lifestyle modifications.

Pro Tips

Use the CKD-EPI 2021 equation

This calculator uses the 2021 race-free equation recommended by KDIGO and NKF. Avoid older formulas (MDRD, CKD-EPI 2009 with race) which are now considered outdated.

Don't diagnose CKD from one value

CKD requires eGFR <60 or kidney damage markers (proteinuria, hematuria) sustained for ≥3 months. A single low eGFR may reflect acute illness, dehydration, or lab variation. Assess for acute metabolic issues with [Anion Gap](/tools/anion-gap) or [Corrected Calcium](/tools/corrected-calcium).

Track the trend over time

A stable eGFR of 55 is very different from an eGFR declining from 75→55 over one year. Plot serial values to identify rapid progressors who need aggressive intervention.

Check creatinine units carefully

US labs report creatinine in mg/dL; international labs use μmol/L. The difference is ~88-fold. Entering the wrong unit produces wildly inaccurate eGFR.

Consider cystatin C when creatinine is unreliable

In patients with extremes of muscle mass (bodybuilders, amputees, cachexia), cystatin C–based eGFR or a combined creatinine-cystatin C equation is more accurate.

Know when eGFR doesn't apply

eGFR is invalid in acute kidney injury (rapidly changing creatinine), pregnancy, children <18, and extreme body size. Use other assessments in these populations.

Pair with urine albumin-to-creatinine ratio (UACR)

KDIGO staging uses both eGFR and albuminuria. Two patients with eGFR 50 have very different prognoses if one has UACR 30 vs. 300 mg/g. For patients with cirrhosis and CKD (hepatorenal syndrome), also calculate [MELD Score](/tools/meld-score).

Watch for drugs that raise creatinine without harming kidneys

Trimethoprim, cimetidine, and cobicistat inhibit tubular creatinine secretion, raising serum creatinine ~0.2 mg/dL without affecting true GFR. This causes falsely low eGFR.

Refer to nephrology at eGFR <30

KDIGO recommends nephrology referral for CKD G4–G5 (eGFR <30), rapid decline (>5 mL/min/year), or persistent significant proteinuria. Earlier referral improves outcomes. For patients with concurrent liver disease, calculate [MELD Score](/tools/meld-score) to assess transplant candidacy.

Educate patients about modifiable risk factors

Blood pressure control, diabetes management, avoiding NSAIDs, and ACE inhibitor/ARB use are the pillars of CKD management. eGFR decline can be slowed significantly.

Common Questions About Your Results

Evidence-Based Methodology

This calculator implements the CKD-EPI 2021 creatinine equation, recommended by KDIGO (Kidney Disease: Improving Global Outcomes), the National Kidney Foundation, and the American Society of Nephrology. The race-free equation was adopted following the 2021 NKF-ASN Task Force report on reassessing the inclusion of race in diagnosing kidney diseases.

Clinical Content Trust

Last reviewed:: April 21, 2026
Guideline version:: General evidence framework v2026.04
Source set version:: Primary-source set v1

How to Interpret Your Result

Your eGFR result is reported in mL/min/1.73 m² and corresponds to a CKD stage. An eGFR of 90 or above (G1) indicates normal kidney function, though kidney disease may still be present if there are other markers such as proteinuria. An eGFR of 60–89 (G2) suggests mildly decreased function. Stage G3a (45–59) and G3b (30–44) represent moderate kidney function loss and are the stages where clinical management to slow progression becomes critical. Stage G4 (15–29) is severe loss, and G5 (below 15) indicates kidney failure where dialysis or transplant may be necessary.

A single eGFR value is a snapshot — kidney function should be confirmed with repeat testing over at least 3 months before diagnosing CKD. Trending eGFR over time is more clinically meaningful than any individual reading.

When to Use This Tool

eGFR is used in routine screening for chronic kidney disease, particularly in patients with risk factors such as diabetes, hypertension, cardiovascular disease, or a family history of kidney failure. It is also essential when prescribing medications that are renally cleared, as many drugs require dose adjustments based on kidney function.

Clinicians use eGFR to monitor CKD progression over time, assess eligibility for nephrology referral (generally recommended at eGFR < 30 or with rapidly declining function), and guide decisions about dialysis planning.

Limitations

eGFR equations estimate filtration from serum creatinine, which is influenced by muscle mass. The result may overestimate kidney function in patients with low muscle mass (e.g., elderly, malnourished, amputees) and underestimate it in very muscular individuals.

The CKD-EPI 2021 equation is validated for adults aged 18 and older and should not be used in children or pregnant women. Acute kidney injury (AKI) cannot be assessed with eGFR — when creatinine is rapidly changing, eGFR does not reflect real-time filtration.

Certain substances (e.g., trimethoprim, cimetidine) can elevate serum creatinine without affecting actual kidney function, producing a falsely low eGFR. Cystatin C–based equations may be preferred when creatinine-based estimates are unreliable.

Compare guidelines:

Select a guideline above to see how thresholds differ by organization and region.

Disclaimer: This tool is for educational and informational purposes only. It is not a substitute for professional medical advice, diagnosis, or treatment. Always consult a qualified healthcare provider with questions about your health.

Sources

Changelog

April 21, 2026 · trust-baseline
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