Health Calculators

Health Calculators — Quick 8‑Section Guide

A fast, practical framework to use our BMI, BMR, TDEE, macros, pregnancy, and medical calculators effectively—without fluff.

1) Core idea

Each tool computes a single health metric using well‑known formulas (for example: BMI = kg/m², Mifflin‑St Jeor for BMR, activity multipliers for TDEE, Naegele’s rule for due date). Results are instant and calculated locally in your browser.

2) Flow

• Pick units (US or metric) and enter inputs
• We convert exactly (1 in = 2.54 cm; 1 lb = 0.45359237 kg)
• We apply the selected equation and show results plus ranges
• Use related tools to cross‑check (for example BMI → Body Fat → TDEE)

3) Sanity checks

• Height and weight in plausible ranges (no zeros/negatives)
• Ages within human ranges for the specific tool
• Pregnancy dates within 37–42 weeks window
• Activity multipliers exactly: 1.2, 1.375, 1.55, 1.725, 1.9 (and 2.0 where provided)

4) Shortcuts

• Quick convert: ft/in → cm with 1 in = 2.54 cm
• lb ↔ kg with 1 lb = 0.45359237 kg
• BMI in US units uses the exact 703 factor

5) Pitfalls

• BMI can misclassify muscular athletes—pair with Body Fat
• TDEE depends on honest activity selection; adjust after 2–3 weeks
• Due dates are estimates; irregular cycles need ultrasound dating

6) Micro examples

• BMI: 70 kg, 175 cm → 70 / 1.75² = 22.9
• BMR (MSJ, male): 10×70 + 6.25×175 − 5×30 + 5 = 1663.8 kcal
• TDEE (moderate 1.55): 1664 × 1.55 ≈ 2579 kcal
• Due date: LMP + 280 days (adjust for cycle length)

7) Mini‑FAQ

• Accuracy? Equations are standard; real‑world needs vary
• Privacy? All calculations run in your browser
• Which BMR? Use Mifflin‑St Jeor; Katch‑McArdle if body‑fat % is known

8) Action tip

Chain tools for clarity: BMI → Body Fat → BMR → TDEE → Calorie/Macro targets; review progress weekly and adjust ±100–200 kcal as needed.