{"uid":"cap_am-5M_DykJE3lk7JMFXQd","slug":"one-rep-max-calculator-epley-brzycki-lombardi-o-conner-3aee4a0a","name":"One-Rep Max Calculator (Epley, Brzycki, Lombardi, O'Conner)","description":"Estimated one-rep max from weight and reps by the Epley, Brzycki, Lombardi and O'Conner formulas, with a percentage table.","url":"https://fitness-calc.x402tookit.com/one-rep-max?utm_source=zero.xyz","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"],"type":"string"},"queryParams":{"type":"object","required":["weight","reps"],"properties":{"reps":{"type":"integer","description":"Repetitions to failure or near failure, 1 to 20"},"weight":{"type":"number","description":"Weight lifted (any unit)"}}}},"additionalProperties":false},"output":{"type":"object","required":["type"],"properties":{"type":{"type":"string"},"example":{"type":"object","properties":{"asOf":{"type":["null","string"]},"reps":{"type":["null","number"]},"epley":{"type":["null","number"]},"source":{"type":["null","string"]},"weight":{"type":["null","number"]},"average":{"type":["null","number"]},"brzycki":{"type":["null","number"]},"oconner":{"type":["null","number"]},"reasons":{"type":["array","null"],"items":{"type":"string"}},"summary":{"type":["null","string"]},"verdict":{"type":["null","string"]},"degraded":{"type":["boolean","null"]},"lombardi":{"type":["null","number"]},"disclaimer":{"type":["null","string"]},"notChecked":{"type":["array","null"],"items":{"type":"string"}},"percentOfAverage":{"type":["null","object"],"properties":{"50%":{"type":["null","number"]},"60%":{"type":["null","number"]},"65%":{"type":["null","number"]},"70%":{"type":["null","number"]},"75%":{"type":["null","number"]},"80%":{"type":["null","number"]},"85%":{"type":["null","number"]},"90%":{"type":["null","number"]},"95%":{"type":["null","number"]}}}}}}}}},"responseSchema":null,"example":null,"exampleRequest":null,"tags":["x402"],"displayCostAmount":"0.02","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":"$0.02/call","primary":{"kind":"static","protocol":"x402","network":"base","amountUsd":"0.02","per":"call","confidence":"exact"},"accepted":[{"kind":"static","protocol":"x402","network":"base","amountUsd":"0.02","per":"call","confidence":"exact"}]},"paymentMethods":[{"uid":"pm_7XNyn1DmEbEU-UIirdyy8","protocol":"x402","methodType":"crypto","chain":"base","mode":"charge","costAmount":"0.02","costPer":"request","priority":0,"asset":"0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913","unit":"request","depositMicros":null,"planRef":null}],"brandName":null,"brandSlug":null,"brandBaseUrl":null,"brandDocsUrl":null,"whatItDoes":"Estimates one-repetition maximum (1RM) strength from a given weight and rep count using four established formulas, and returns a percentage table of training loads.","exampleAgentPrompt":"I squatted 135kg for 6 reps — can you estimate my one-rep max using Epley, Brzycki, Lombardi, and O'Conner, and give me a percentage table so I know what weights to use for different training intensities?","exampleUseCases":[{"title":"Powerlifter setting training weights","prompt":"I deadlifted 180kg for 3 reps today — what's my estimated one-rep max across the main formulas, and what weights should I be using at 70%, 80%, and 90% intensity?"},{"title":"Gym-goer tracking strength progress","prompt":"Last month I benched 80kg for 8 reps and now I can do 80kg for 12 reps — can you calculate my current estimated 1RM so I can see how much stronger I've gotten?"},{"title":"Coach planning athlete programming","prompt":"My athlete hit 100 pounds on overhead press for 5 reps — please estimate their one-rep max using all four formulas and show me the full percentage table so I can program their accessory lifts."}],"resultDescription":"Returns the input weight and reps echoed back, four separate 1RM estimates (Epley, Brzycki, Lombardi, O'Conner), an average of all four, a percentage-of-average table at 50%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, and 95% of 1RM, plus a summary, verdict, disclaimer, and source attribution. May include a degraded flag and reasons if the calculation is outside reliable range.","failureModes":["Missing required 'weight' or 'reps' query parameters returns an error","Reps value outside the 1–20 range may produce unreliable or flagged estimates with degraded=true","Non-numeric weight or reps values will fail validation","Very high rep counts (near 20) produce less accurate estimates as formulas lose reliability","Payment not received results in HTTP 402 response"],"whenToPreferThis":"Choose this endpoint when you need a quick, multi-formula 1RM estimate without performing an actual max-effort lift. It is ideal for strength athletes, coaches, and fitness apps that need to program training percentages from sub-maximal performance data. Preferred over manual calculation because it returns all four major formulas simultaneously with a ready-to-use percentage load table.","instructions":null,"reviewSummary":null,"reviewSummaryHighlights":null,"reviewSummaryConcerns":null,"reviewSummaryGeneratedAt":null,"activationCount":0,"lastUsedAt":null,"lastSuccessfullyRanAt":null,"lastHealthCheckAt":"2026-10-29T13:14:27.280Z","isFirstParty":false,"canonicalSlug":"one-rep-max-calculator-epley-brzycki-lombardi-o-conner-3aee4a0a"}