Kidney Health · Clinical

GFR
Calculator

Calculate estimated Glomerular Filtration Rate (eGFR) for adults and children. Uses CKD-EPI (2021) and MDRD formulas for adults, Schwartz formula for children. Includes full CKD staging guide.

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eGFR (mL/min)

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CKD Stage

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Kidney Function

Calculate eGFR

Age

yrs

Serum Creatinine

mg/dL

Formula

⚕️ CKD-EPI 2021 is the preferred formula per KDIGO guidelines. MDRD may underestimate GFR in healthy individuals.

Age

yrs

Height

Serum Creatinine

mg/dL

👶 Uses the Bedside Schwartz formula: eGFR = 0.413 × (Height/Creatinine). Validated for children 1–16 years.

⚠️ This calculator is for educational purposes only. GFR values should always be interpreted by a qualified healthcare provider in the context of complete clinical assessment.

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Estimated GFR

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mL/min/1.73 m²

Enter values

Fill in the form above to see your eGFR

Formula

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Function

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eGFR

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CKD Stage

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Kidney Fn %

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Status

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🩺 CKD Staging by eGFR (KDIGO Guidelines)

01530456090120+

Stage 1

Normal/High

eGFR ≥ 90. Normal or high kidney function. Presence of kidney damage markers may still indicate CKD.

≥ 90

Stage 2

Mildly Decreased

eGFR 60–89. Mild reduction, usually asymptomatic. Monitor regularly. Control BP and blood sugar.

60–89

Stage 3a

Mild-Moderate

eGFR 45–59. Moderate CKD. Regular nephrology visits. Limit nephrotoxic drugs. RAAS therapy.

45–59

Stage 3b

Moderate-Severe

eGFR 30–44. Significant CKD. Anemia and bone disease management. Prepare for renal replacement therapy.

30–44

Stage 4

Severe

eGFR 15–29. Severe CKD. Begin dialysis/transplant planning. Close monitoring of electrolytes and fluid.

15–29

Stage 5

Kidney Failure

eGFR < 15. Kidney failure (end-stage renal disease). Dialysis or kidney transplant typically required.

< 15

Understanding eGFR and Kidney Function

The Glomerular Filtration Rate (GFR) is the gold standard measurement of kidney function. It estimates how many milliliters of blood the kidneys filter per minute per 1.73 m² of body surface area. Because direct measurement is invasive, clinicians use estimated GFR (eGFR) calculated from serum creatinine, age, and sex.

GFR Formulas

CKD-EPI 2021 (Adults — recommended by KDIGO): If creatinine ≤ κ: 141 × (Cr/κ)^−0.329 × 0.9929^Age × [1.018 if female] If creatinine > κ: 141 × (Cr/κ)^−1.209 × 0.9929^Age × [1.018 if female] κ = 0.7 (female), 0.9 (male) MDRD (4-variable): 175 × Cr^−1.154 × Age^−0.203 × [0.742 if female] Bedside Schwartz (Children): eGFR = 0.413 × (Height in cm / Serum Creatinine in mg/dL)

⚠️ Medical Disclaimer: This calculator provides estimates for educational purposes only. Results must be interpreted by a qualified medical professional in the context of a complete clinical evaluation including symptoms, medical history, repeat testing, and urine albumin measurements. Do not make medical decisions based solely on these results.

Frequently Asked Questions

Can I improve my GFR?

Depending on the cause of kidney disease, GFR can sometimes be improved or stabilized. Key interventions include: optimal blood pressure control (<130/80 mmHg), blood glucose management in diabetes, protein intake moderation (0.8g/kg/day for CKD Stages 3–5), avoiding NSAIDs and nephrotoxic agents, stopping smoking, and staying well-hydrated. ACE inhibitors or ARBs protect kidney function in diabetic nephropathy and proteinuric CKD.

Why does creatinine affect GFR calculations?

Creatinine is a waste product of muscle metabolism that is filtered by the kidneys at a relatively constant rate. When kidney function declines, creatinine accumulates in the blood. The inverse relationship between serum creatinine and GFR allows estimation of filtration rate. However, creatinine levels are also affected by muscle mass — athletes and muscular individuals have higher baseline creatinine, which may give a falsely low eGFR, while elderly, malnourished, or amputee patients may have falsely high eGFR estimates.

What other tests complement GFR in assessing kidney health?

eGFR alone doesn't tell the complete story. Key complementary tests include: urine albumin-to-creatinine ratio (ACR) to detect kidney damage; serum electrolytes (sodium, potassium, bicarbonate, phosphate); blood urea nitrogen (BUN); complete blood count for anemia; blood pressure; imaging (ultrasound to assess kidney size and structure); and parathyroid hormone (PTH) for bone-mineral metabolism in CKD.

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