Corrected Calcium Calculator
Albumin-corrected calcium in mg/dL or mmol/L.
Enter your values to see the result.
Payne's formula: corrected Ca = measured Ca + 0.8 × (4 − albumin) in mg/dL, or + 0.02 × (40 − albumin) in mmol/L. Ionized calcium is more reliable in critical illness and kidney failure. For education and clinical decision support only. Results do not replace professional judgment, local protocols or the product information, so always verify doses and values before acting on them.
Continue your work
- Medical Lab Unit Converter — Convert calcium and albumin units.
- Anion Gap Calculator — Check other electrolytes.
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Clear instructions
Find steps, examples and limitations below.
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How to use the Corrected Calcium Calculator
Albumin-corrected calcium in mg/dL or mmol/L.
- 1 Choose conventional (mg/dL, g/dL) or SI (mmol/L, g/L) units.
- 2 Enter total calcium and serum albumin.
- 3 Read the corrected calcium and its interpretation.
Example and practical tips
Calcium 8.2 mg/dL with albumin 2.8 g/dL corrects to 9.16 mg/dL (2.29 mmol/L), which is within the normal range.
Further reading
Frequently asked questions
Why correct calcium for albumin?
About 40% of calcium is bound to albumin, so low albumin lowers total calcium while the active ionized calcium may be normal.
When should ionized calcium be measured instead?
In critical illness, kidney failure and acid–base disturbances the correction is unreliable, so measure ionized calcium directly.
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