Winters Formula (Expected PaCO2)
Predicted respiratory compensation for a given serum bicarbonate (mEq/L).
Calculator
How it works
Winters formula estimates the PaCO2 that would accompany isolated metabolic acidosis if ventilation compensates in the classic 1:1.5 relationship taught for chronic compensation.
Expected PaCO2 ≈ 1.5 × [HCO3] + 8 mmHg (±2 mmHg teaching band)
Limits
Not reliable in acute respiratory changes, primary respiratory disorders, or triple acid–base disturbances. Always interpret with pH, anion gap, and clinical context.
Educational tool only—not for diagnosis or treatment decisions.