Winter's Formula (Expected PaCO₂ in Metabolic Acidosis) | Online Free Tool | Elysia Tools
Elysia Tools
Navigation
Health
Winter's Formula (Expected PaCO₂ in Metabolic Acidosis)
Calculate expected respiratory compensation PaCO₂ for metabolic acidosis: 1.5×HCO₃⁻ + 8 ± 2 mmHg. Classifies compensation as appropriate or flags mixed disorders. Derived from Albert 1967, Emmett 2016, LITFL, MDCalc. Not medical advice.
Execution
Run this tool
Fill in the form, run the tool, and review the result in one place.
Samples
Examples that match this tool
Related
Continue with connected tools and hubs
Result
Ready for a run
Run the tool to preview files, text, structured data, or streamed output here.
Tool usage guide
Learn when to use this tool, what it supports, and how real users apply it.
Key facts
Category
Health
Input types
number
Output type
json
Sample coverage
4
API ready
Yes
Overview
Winter's Formula calculator estimates the expected PaCO₂ for respiratory compensation in metabolic acidosis using 1.5 × HCO₃⁻ + 8 ± 2 mmHg. Enter bicarbonate and optionally measured PaCO₂ to assess whether compensation is appropriate or whether a mixed respiratory disorder may be present. Not medical advice.
When to use
Estimate expected respiratory compensation when metabolic acidosis is present.
Compare a measured arterial PaCO₂ with the expected compensation range.
Screen for possible concomitant respiratory acidosis or respiratory alkalosis.
How it works
1Enter serum or arterial blood gas bicarbonate in mmol/L.
HCO₃⁻: 15 mmol/L; actual PaCO₂: 40 mmHg; decimal places: 1
Outcome
Expected PaCO₂ is 30.5 ± 2 mmHg, with a range of 28.5–32.5 mmHg. The measured PaCO₂ of 40 is above the range, indicating concomitant respiratory acidosis.