Phosphate (as phosphorus) mmol/L → mg/dL
Convert phosphate (as phosphorus) from mmol/L to mg/dL
Sources last checked: 2026-11-03
Phosphate (as phosphorus) mmol/L → mg/dL
Convert phosphate (as phosphorus) from mmol/L to mg/dL
Converts units only; reference ranges depend on the laboratory, the assay and the patient.
What is the Phosphate (as phosphorus) mmol/L → mg/dL?
This converter turns serum phosphate from mmol/L, used by many labs in Germany, Austria, the UK and Scandinavia, into mg/dL of phosphorus, the unit common in Turkey and the USA. It divides by 0.3229 (equivalent to multiplying by about 3.097), which follows from the atomic mass of phosphorus, 30.974 g/mol.
When to use it
- Reading US or Turkish nephrology and CKD-MBD literature with an SI result
- Entering phosphate into a protocol or form that expects mg/dL
- Comparing results across labs with different units
When not to use it
- Urinary phosphate excretion per 24 h — check whether it is given in mmol/24 h or g/24 h and convert accordingly
- Judging hyper- or hypophosphataemia: reference ranges depend on age and laboratory
How it is calculated
Phosphate as phosphorus (mg/dL) = phosphate (mmol/L) ÷ 0.3229
Clinical pearls and limitations
- Converts units only; reference ranges depend on the laboratory, the assay and the patient.
- The mg/dL result is milligrams of phosphorus, not of the phosphate ion; this is the convention of virtually all clinical labs.
- A rough check: 1 mmol/L is about 3.1 mg/dL.
- Some phosphate binders and parenteral products are dosed in mmol of phosphate; that is a dose unit, not a serum concentration.
- Results after a meal or at different times of day are not directly comparable.
Frequently asked questions
How do I convert phosphate from mmol/L to mg/dL?
Divide by 0.3229. For example, 1.13 mmol/L ÷ 0.3229 = 3.4995, about 3.5 mg/dL.
What is 1 mmol/L phosphate in mg/dL?
1 ÷ 0.3229 = 3.097, about 3.1 mg/dL.
Why not use the molar mass of phosphate (PO₄)?
Because the mg/dL value on lab reports expresses the phosphorus content. Using the larger mass of the phosphate ion would give a wrong, much higher mg/dL value.
Evidence and guidelines
Have a follow-up question?
Medelix answers clinical questions from current guidelines and studies — every statement with its source.
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<p><a href="https://medelix.ai/en/calculators/phosphate-mmol-l-to-mg-dl">Phosphate (as phosphorus) mmol/L → mg/dL calculator by Medelix</a></p>For healthcare professionals and medical students. These tools support, and do not replace, clinical judgement. Always check results against the original source and your local protocols.