Corrected Calcium
Measured total calcium
Serum albumin
Enter the measured calcium and albumin to see the corrected value.
The correction is unreliable in critical illness, significant CKD, and marked acid-base disturbance — measure ionised calcium where the answer actually matters.
Show formula
Corrected Ca (mmol/L) = measured Ca + 0.02 × (40 − albumin g/L)
Equivalently in US units: measured Ca + 0.8 × (4.0 − albumin g/dL)
Source: Payne RB, Little AJ, Williams RB, Milner JR. Interpretation of serum calcium in patients with abnormal serum proteins. Br Med J. 1973;4(5893):643–646.