# Services from fitness-calc.x402tookit.com on Zero

> fitness-calc.x402tookit.com serves 10 paid API services for AI agents, indexed by Zero. Each is callable per call with payment handled by Zero.

Canonical page: https://www.zero.xyz/host/fitness-calc.x402tookit.com
Live health (JSON, refreshed every minute): https://www.zero.xyz/host/fitness-calc.x402tookit.com/health.json

## Services

- [One-Rep Max Calculator (Epley, Brzycki, Lombardi, O'Conner)](https://www.zero.xyz/c/one-rep-max-calculator-epley-brzycki-lombardi-o-conner-3aee4a0a/llms.txt): $0.02/call via x402. 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.
- [Pregnancy Due Date Calculator (Naegele Rule)](https://www.zero.xyz/c/pregnancy-due-date-calculator-naegele-rule-546a42ad/llms.txt): $0.02/call via x402. Calculates estimated due date, gestational age, trimester, and key pregnancy milestones from the last menstrual period date using the Naegele rule.
- [Fitness and Body Calculators – Calorie Burn by Activity](https://www.zero.xyz/c/fitness-and-body-calculators-calorie-burn-by-activity-4990e6ad/llms.txt): $0.02/call via x402. Calculates calories burned during a physical activity using MET values, body weight, and duration.
- [Heart Rate Zones Calculator](https://www.zero.xyz/c/heart-rate-zones-calculator-ee20a4fc/llms.txt): $0.02/call via x402. Calculates estimated maximum heart rate (Tanaka and Fox formulas) and five training zones by percentage of max or heart-rate reserve (Karvonen method) from age and optional resting HR.
- [Fitness and Body Calculators – Macro Split](https://www.zero.xyz/c/fitness-and-body-calculators-macro-split-3b31d67b/llms.txt): $0.02/call via x402. Calculates protein, carbohydrate, and fat grams from a daily calorie target using a preset ratio or custom percentage split.
- [BMR, TDEE & Calorie Target Calculator](https://www.zero.xyz/c/bmr-tdee-calorie-target-calculator-8fd28ce5/llms.txt): $0.02/call via x402. Calculates basal metabolic rate (Mifflin-St Jeor), total daily energy expenditure by activity level, and a calorie target adjusted for a desired weekly weight change.
- [Running Pace & Race Prediction Calculator](https://www.zero.xyz/c/running-pace-race-prediction-calculator-7e01651b/llms.txt): $0.02/call via x402. Calculates running pace per km and per mile, speed in km/h and mph, and predicts finish times for other race distances using the Riegel formula from a given distance and finish time.
- [Ideal Body Weight Calculator (Devine, Robinson, Miller, Hamwi)](https://www.zero.xyz/c/ideal-body-weight-calculator-devine-robinson-miller-hamwi-c78b015d/llms.txt): $0.02/call via x402. Calculates ideal body weight in kg and pounds using four clinical formulas (Devine, Robinson, Miller, Hamwi) given height and sex.
- [BMI Calculator with WHO Category and Healthy Weight Range](https://www.zero.xyz/c/bmi-calculator-with-who-category-and-healthy-weight-range-fc320922/llms.txt): $0.02/call via x402. Calculates body mass index from weight and height (metric or imperial), returns the WHO adult category, and the healthy weight range for normal BMI (18.5–24.9).
- [US Navy Body Fat Percentage Calculator](https://www.zero.xyz/c/us-navy-body-fat-percentage-calculator-f900b166/llms.txt): $0.02/call via x402. Estimates body fat percentage using the US Navy tape-measure method, returning fat mass, lean mass, and body composition category from circumference measurements.

Status and success rate cover calls made through Zero and Zero's own probes. Third-party monitors may report differently.

- [Zero catalog index](https://www.zero.xyz/llms.txt)