A Calculator to Estimate the 24-Hour Urine Protein from a Spot Urine Protein-to-Creatinine Ratio

24h Protein Estimator

Estimates 24-hour urine protein from spot UPCR using the validated multivariate Chen 2019 equation.

Chen et al. PLoS ONE 2019;14(4):e0214614

Clinical caveat: Validated for proteinuria <3 g/day. Agreement with measured 24h UP weakens above this threshold (Bland-Altman). For suspected nephrotic-range disease, a timed 24h collection remains the reference standard.

Patient Inputs

Spot UPCR mg/mg

mg/mg

Urine protein (mg/dL) ÷ Urine creatinine (mg/dL)

Body Weight kg

kg

Age years

yr

Sex at Birth

Male = 1, Female = 0 per published equation

CKD Stage

eGFR (mL/min/1.73m²) shown. G3a selected as default.

Please fill in all fields.

Estimated 24-Hour Urine Protein

— g / day

—

log₁₀(24hUP)

—

UPCR Input

—

log₁₀(UPCR)

—

CKD Stage Coeff

—

Proteinuria Severity — KDIGO Categories

00.150.51.03.5>3.5 g

Equation Reference

log₁₀(24hUP [g]) = 0.814 × log₁₀(UPCR) + 0.110 × Gender − 0.004 × Age + 0.004 × Weight(kg) + 0.002 × CKD coeff − 0.018

Variable	Coefficient	Encoding
log₁₀(UPCR)	0.814	UPCR in mg/mg
Gender	+0.110	Male = 1, Female = 0
Age	−0.004	years
Weight	+0.004	kg
CKD Stage Coeff	+0.002	G1=1, G2=2, G3a=3.1, G3b=3.2, G4=4, G5=5
Intercept	−0.018	—

Validation: Derivation cohort r = 0.866; Validation cohort r = 0.915. R² = 0.80 vs. 0.67 for unadjusted UPCR. Validated in 1,120 CKD patients, Chang Gung Memorial Hospital, Taiwan (PLoS ONE 2019).

For clinical decision support only. This calculator aids clinical judgment and does not replace physician assessment or timed urine collections. Not validated for AKI, pregnancy-related proteinuria, or dialysis patients.