One Rep Max Calculator

Calculators REST API MCP

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.

This page documents the MCP tool findutils:one_rep_max_calculator. See the REST reference →

Use in the browser View as Markdown

Call it over MCP

Tool name findutils:one_rep_max_calculator · no API keys · 120 requests/min per IP

Claude Code

claude mcp add findutils --transport http https://mcp.findutils.com/

Claude Desktop — claude_desktop_config.json

{
  "mcpServers": {
    "findutils": {
      "url": "https://mcp.findutils.com/"
    }
  }
}

Raw JSON-RPC (any MCP client) — verified example

curl -X POST https://mcp.findutils.com/ \
  -H "Content-Type: application/json" \
  -d '{
    "jsonrpc": "2.0",
    "id": 1,
    "method": "tools/call",
    "params": {
      "name": "one_rep_max_calculator",
      "arguments": {
        "weight": 100,
        "reps": 5
      }
    }
  }'

Input schema

Argument	Type	Required	Description
weight	number	yes	Weight lifted, in the chosen unit.
reps	integer	yes	Reps performed with that weight (1-30).
unit	string (kg \| lbs)	no	Weight unit, echoed back in the result. Default: "kg".
formula	string (brzycki \| epley \| lander \| lombardi \| mayhew \| oconner \| wathen)	no	Formula used for the headline one_rep_max. Default: "brzycki".

Example arguments (verified)

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

Also a REST endpoint

The same tool answers plain HTTP at POST /api/tools/one-rep-max-calculator/execute — no key, 60 requests/min.

Open the REST reference for One Rep Max Calculator →

More Calculators tools

Ass To Srt

Flatten an Advanced SubStation Alpha (.ass) or SubStation Alpha (.ssa) subtitle script to plain SubRip (.srt).

Bmi Calculate

Compute Body Mass Index (BMI) with metric (kg/cm) or imperial (lb/in) units.

Body Fat Calculator

Estimate body fat percentage, fat mass, lean mass, BMI, and a body-composition category.

Carbon Footprint Calculator

Estimate an annual personal carbon footprint in tonnes of CO2 from home energy, transportation, and lifestyle, with a per-category breakdown

Chmod Calculate

Convert between numeric (755) and symbolic (rwxr-xr-x) Unix file permissions.

Cloudflare Cost Calculate

Estimate monthly Cloudflare developer platform costs (Workers, D1, R2, KV, Durable Objects) under free or $5 Workers Paid plans.

Daily Habit Calculator

Calculate how a daily habit adds up over a week, a month (30 days), a year (365 days), or a custom date range: total units, total cost, and

Gcd Calculate

Greatest Common Divisor (GCD) and Least Common Multiple (LCM) of two non-negative integers.