{"uid":"cap_U-67PZP4gLTmQ8YiuE3Pk","slug":"winters-formula-pco2-calculator-metabolic-acidosis-compensation-61dfa85e","name":"Winters' Formula PCO2 Calculator (Metabolic Acidosis Compensation)","description":"Winters' formula for expected PCO2 in metabolic acidosis: 1.5 × bicarbonate + 8 mm Hg, with a published ±2 mm Hg range. Optional comparison of measured PaCO2 to that band. Deterministic Albert–Winters 1967 arithmetic with citation; not a treatment target or a metabolic alkalosis formula.","url":"https://api.magentlab.com/api/calc/winters","method":"GET","headers":{},"bodySchema":{"type":"object","$schema":"https://json-schema.org/draft/2020-12/schema","required":["input"],"properties":{"input":{"type":"object","required":["type","method"],"properties":{"type":{"type":"string","const":"http"},"method":{"enum":["GET","HEAD","DELETE"],"type":"string"},"headers":{"type":"object","additionalProperties":{"type":"string"}},"queryParams":{"type":"object","required":["bicarbonate_mmol_l"],"properties":{"paco2_mm_hg":{"type":"number","description":"Measured arterial PCO2 in mm Hg (8-80). When supplied, compensation is returned versus the Winters ±2 band."},"bicarbonate_mmol_l":{"type":"number","description":"Plasma bicarbonate in mmol/L (2-24). Metabolic acidosis range."}}}},"additionalProperties":false},"output":{"type":"object","required":["type"],"properties":{"type":{"type":"string"},"example":{"type":"object"}}}}},"responseSchema":{"type":"json","example":{"path":"/api/calc/winters","count":2,"items":[{"formula":"winters","citation":{"id":"albert-winters-1967","doi":"10.7326/0003-4819-66-2-312","title":"Quantitative displacement of acid-base equilibrium in metabolic acidosis","source":"Ann Intern Med. 1967;66(2):312-322","authors":"Albert MS, Dell RB, Winters RW"},"disclaimer":"Not a medical device. Deterministic published-formula or published-code output for autonomous agents. A licensed clinician remains responsible for patient care and billing submissions.","bicarbonate_mmol_l":12,"formula_expression":"expected_pco2_mm_hg = 1.5 * bicarbonate_mmol_l + 8","expected_pco2_mm_hg":26,"expected_pco2_low_mm_hg":24,"expected_pco2_high_mm_hg":28},{"formula":"winters","citation":{"id":"albert-winters-1967","doi":"10.7326/0003-4819-66-2-312","title":"Quantitative displacement of acid-base equilibrium in metabolic acidosis","source":"Ann Intern Med. 1967;66(2):312-322","authors":"Albert MS, Dell RB, Winters RW"},"disclaimer":"Not a medical device. Deterministic published-formula or published-code output for autonomous agents. A licensed clinician remains responsible for patient care and billing submissions.","bicarbonate_mmol_l":12,"formula_expression":"expected_pco2_mm_hg = 1.5 * bicarbonate_mmol_l + 8","expected_pco2_mm_hg":26,"expected_pco2_low_mm_hg":24,"expected_pco2_high_mm_hg":28}]}},"example":null,"exampleRequest":null,"tags":["x402"],"displayCostAmount":"0.005","displayCostAsset":"USDC","priceDynamic":false,"priceHint":null,"priceStatus":"priced","priceSource":"probe","requiresHandshake":false,"reviewCount":0,"rating":{"score":"0.00","successRate":"0.00","reviews":0,"stars":null,"state":"unrated"},"availabilityStatus":"unknown","priceObserved":null,"sessionDeposit":null,"pricing":{"kind":"static","summary":"$0.005/call","primary":{"kind":"static","protocol":"x402","network":"base","amountUsd":"0.005","per":"call","confidence":"exact"},"accepted":[{"kind":"static","protocol":"x402","network":"base","amountUsd":"0.005","per":"call","confidence":"exact"}]},"paymentMethods":[{"uid":"pm_OqdHPpaqQRXdR1sosZ5IM","protocol":"x402","methodType":"crypto","chain":"base","mode":"charge","costAmount":"0.005","costPer":"request","priority":0,"asset":"0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913","unit":"request","depositMicros":null,"planRef":null}],"brandName":null,"brandSlug":null,"brandBaseUrl":null,"brandDocsUrl":null,"whatItDoes":"Calculates expected PaCO2 using Winters' formula (1.5 × HCO3 + 8 ±2 mmHg) and optionally compares a measured PaCO2 to determine if respiratory compensation is adequate, excessive, or insufficient.","exampleAgentPrompt":"My patient has a metabolic acidosis with a bicarbonate of 14 mmol/L and a measured PaCO2 of 30 mm Hg — run Winters' formula and tell me if the respiratory compensation is appropriate.","exampleUseCases":[{"title":"ICU ABG compensation check","prompt":"I have an ICU patient in metabolic acidosis with a bicarb of 10 mmol/L and a PaCO2 of 28 mm Hg — use Winters' formula to tell me if their respiratory compensation is adequate, excessive, or insufficient."},{"title":"Compute expected PCO2 only","prompt":"What is the expected PaCO2 range for a patient with a plasma bicarbonate of 18 mmol/L using Winters' formula? I don't have the measured PaCO2 yet, just give me the target range."},{"title":"Teaching case ABG interpretation","prompt":"For a medical student case with bicarbonate of 8 mmol/L and PaCO2 of 20 mm Hg, calculate the Winters' expected PCO2 and tell me whether the compensation is appropriate."}],"resultDescription":"Returns the Winters' formula expected PaCO2 (1.5 × bicarbonate + 8 mm Hg) with the ±2 mm Hg band (lower and upper bounds). If a measured PaCO2 is provided, also returns whether the measured value falls within, below, or above the expected compensation band, indicating adequate, excessive (possible concomitant respiratory alkalosis), or insufficient (possible concomitant respiratory acidosis) compensation.","failureModes":["Bicarbonate value outside valid range (2–24 mmol/L) returns validation error","PaCO2 value outside valid range (8–80 mm Hg) returns validation error","Missing required bicarbonate_mmol_l parameter returns 400 error","Formula is only valid for metabolic acidosis; results are meaningless for normal or alkalotic bicarbonate values"],"whenToPreferThis":"Use this endpoint when you need a fast, citeable, deterministic Winters' formula calculation for metabolic acidosis respiratory compensation assessment. Prefer it over general clinical calculators when you specifically need the Albert–Winters 1967 formulation with the ±2 mm Hg band and optional measured PaCO2 comparison. Not appropriate for metabolic alkalosis (Winter's formula only applies to acidosis), and not a treatment target.","instructions":null,"reviewSummary":null,"reviewSummaryHighlights":null,"reviewSummaryConcerns":null,"reviewSummaryGeneratedAt":null,"activationCount":0,"lastUsedAt":null,"lastSuccessfullyRanAt":null,"lastHealthCheckAt":"2026-09-15T01:16:15.343Z","isFirstParty":false}