Corrected Calcium Calculator
Adjusting total calcium for a low albumin.
g/dL in conventional units, g/L in SI.
The correction misclassifies calcium status in a meaningful minority of patients, especially in critical illness and kidney disease. Ionised calcium is the definitive test.
Corrected calcium
9.20 mg/dL
Within reference range
How the Corrected Calcium Calculator works
Roughly 40% of serum calcium is bound to albumin and biologically inactive. When albumin is low the total calcium falls with it even though the free, active fraction is unchanged — so the raw number understates the true picture unless it is corrected.
Not medical advice. This calculator gives a general estimate, not medical advice. It cannot account for your individual health, medical history, or medication. Talk to a qualified healthcare professional before acting on any result.
Frequently asked questions
What is the corrected calcium formula?
In mg/dL: corrected calcium = measured calcium + 0.8 × (4.0 − albumin in g/dL). In SI units: corrected calcium in mmol/L = measured + 0.02 × (40 − albumin in g/L).
When should calcium be corrected?
Whenever albumin is outside the normal range, which is common in hospital patients, liver disease, nephrotic syndrome and malnutrition. In a patient with normal albumin the correction changes nothing meaningful.
How reliable is the correction?
Moderately, and it is widely criticised. Studies have found it misclassifies calcium status in a substantial minority of patients, particularly in critical illness and kidney disease. Ionised calcium, measured directly, is the definitive test when the answer matters.
What counts as hypercalcaemia?
Typically a corrected calcium above about 10.5 mg/dL (2.6 mmol/L), though reference ranges vary between laboratories. Malignancy and primary hyperparathyroidism account for the large majority of cases.