One Rep Max Calculator API

POST https://api.findutils.com/api/tools/one-rep-max-calculator/execute

Estimate a one-rep max (1RM) from a weight lifted for a number of reps, using Brzycki, Epley, Lander, Lombardi, Mayhew, O'Conner, and Wathen formulas. Returns the chosen formula result, every formula result, and a training-weight table (100% to 60%) with rep ranges and zones.

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Request body

application/json

weight

number required

Weight lifted, in the chosen unit.
reps

integer required

Reps performed with that weight (1-30).
unit

string optional

Weight unit, echoed back in the result. One of kg · lbs. Default "kg".
formula

string optional

Formula used for the headline one_rep_max. One of brzycki · epley · lander · lombardi · mayhew · oconner · wathen. Default "brzycki".

Example arguments

Verified

{
  "weight": 100,
  "reps": 5
}

curl -X POST https://api.findutils.com/api/tools/one-rep-max-calculator/execute \
  -H "Content-Type: application/json" \
  -d '{
    "weight": 100,
    "reps": 5
  }'

const response = await fetch('https://api.findutils.com/api/tools/one-rep-max-calculator/execute', {
  method: 'POST',
  headers: { 'Content-Type': 'application/json' },
  body: JSON.stringify({"weight":100,"reps":5}),
});
const data = await response.json();

import requests

response = requests.post(
    "https://api.findutils.com/api/tools/one-rep-max-calculator/execute",
    json={"weight":100,"reps":5},
)
data = response.json()

$ch = curl_init('https://api.findutils.com/api/tools/one-rep-max-calculator/execute');
curl_setopt_array($ch, [
    CURLOPT_POST => true,
    CURLOPT_HTTPHEADER => ['Content-Type: application/json'],
    CURLOPT_POSTFIELDS => '{"weight":100,"reps":5}',
    CURLOPT_RETURNTRANSFER => true,
]);
$data = json_decode(curl_exec($ch), true);

Also an MCP tool

Call one_rep_max_calculator from Claude, Cursor or any MCP client. Same arguments, same output.

https://mcp.findutils.com

MCP reference

Rate limit: 60 a minute, per IP
Auth: None
REST id: one-rep-max-calculator
MCP name: one_rep_max_calculator
Category: Calculators
Machine-readable: openapi.json · markdown.md

Request body

Example arguments

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