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Creatinine Clearance Calculator

Estimates creatinine clearance in mL/min with the Cockcroft-Gault equation from age, weight, sex and serum creatinine, and, when height is given, also reports the values using ideal (Devine) and adjusted body weight.

When to use

You need the creatinine clearance used by drug-dosing references (renal dose adjustment) for an adult.

Do not use when: You need a BSA-indexed CKD stage (use egfr), the person is under 18, or creatinine is changing rapidly (acute kidney injury).

Formula

CrCl = (140 − age_years) × weight_kg / (72 × Scr_mg_dl) × 0.85 (if female); IBW (Devine) = 50 (male) or 45.5 (female) + 2.3 × (height_in − 60); adjusted BW = IBW + 0.4 × (weight − IBW)

Cockcroft-Gault (1976) overestimates clearance in obesity when actual weight is used and in low muscle mass; many references use ideal weight when actual is below it and adjusted weight above 120–130% of ideal. Results are informational only and not a substitute for clinical judgement or medical advice.

Inputs

Parameter	Type	Unit	Required	Description
`sex`	enum: male \| female		yes	Sex used to select the formula coefficients or thresholds.
`age_years`	number	years	yes	Age in years. Range: ≥ 18, ≤ 120
`weight_kg`	number	kg	yes	Actual body weight in kilograms. Range: > 0, ≤ 700
`creatinine`	number		yes	Serum creatinine in the unit given by creatinine_unit. Range: > 0, ≤ 4000
`creatinine_unit`	enum: mg_dl \| umol_l		default mg_dl	Unit of the serum creatinine value (1 mg/dL = 88.4 µmol/L).
`height_cm`	number	cm	no	Optional height; enables ideal-body-weight and adjusted-body-weight variants. Range: ≥ 120, ≤ 260

Outputs

Output	Type	Unit	Description
`creatinine_clearance_ml_min`	number	mL/min	Cockcroft-Gault clearance using actual body weight.
`ideal_body_weight_kg`	number	kg	Only when height_cm is given.
`adjusted_body_weight_kg`	number	kg	IBW + 0.4 × (actual − IBW); only when height_cm is given.
`creatinine_clearance_ibw_ml_min`	number	mL/min	Cockcroft-Gault using ideal body weight; only when height_cm is given.
`creatinine_clearance_adjusted_ml_min`	number	mL/min	Cockcroft-Gault using adjusted body weight; only when height_cm is given.
`weight_note`	string		Which weight is commonly used for this body size.

Example

Male, 40 y, 70 kg, creatinine 1.0 mg/dL: {"sex":"male","age_years":40,"weight_kg":70,"creatinine":1} → {"creatinine_clearance_ml_min":97.2}

Female, 65 y, 60 kg, 160 cm, creatinine 0.8 mg/dL: {"sex":"female","age_years":65,"weight_kg":60,"creatinine":0.8,"height_cm":160} → {"creatinine_clearance_ml_min":66.4,"ideal_body_weight_kg":52.4,"creatinine_clearance_ibw_ml_min":58}

GET https://tttkmbb.com/api/v1/calculate/creatinine-clearance?sex=male&age_years=40&weight_kg=70&creatinine=1

Machine access

API: GET https://tttkmbb.com/api/v1/calculate/creatinine-clearance (query parameters) or POST with a JSON body {"inputs": {...}}
Schema: https://tttkmbb.com/api/v1/calculators/creatinine-clearance · Markdown: https://tttkmbb.com/medical/creatinine-clearance.md · JSON definition: https://tttkmbb.com/medical/creatinine-clearance.json
MCP: server https://tttkmbb.com/mcp, tool run_calculator with calculator_id="creatinine-clearance"
OpenAPI operationId: calculate_creatinine_clearance
Freshness: static. Authentication: none. Rate limit: fair use (see rate limits).

Sources

FAQ

Which weight should I use?

Common practice: actual weight when it is below ideal weight, ideal weight for normal-weight adults, and adjusted weight when actual weight exceeds about 120% of ideal; follow the specific drug's labelling.

Why is creatinine clearance different from eGFR?

Cockcroft-Gault is an unindexed estimate in mL/min derived in 1976 for a small male cohort; eGFR (CKD-EPI) is indexed to 1.73 m² and validated for staging CKD, not dosing.

Related calculators

eGFR Calculator — CKD-EPI 2021 eGFR for staging kidney disease.
Adjusted Body Weight Calculator — Adjusted body weight for dosing in obesity.
Ideal Weight Calculator — Ideal body weight formulas.