Is the James Smith Calculator completely free?

Yes. 100% free with no sign-up, no email, and no premium tier.

How accurate is the James Smith Calculator?

Uses the Revised Harris-Benedict (1984), accurate within 5–10% for most people.

BMR is calories at rest. TDEE multiplies BMR by activity level to give real daily calorie burn.

Revised Harris-Benedict Formula (Roza & Shizgal, 1984) for BMR, multiplied by activity factor for TDEE.

Every 3–4 weeks or whenever weight changes by 3–5 kg.

1.6–2.2g per kg of bodyweight. Always hit protein first.

Non-Exercise Activity Thermogenesis — calories burned outside formal exercise. Often exceeds gym sessions.

Likely metabolic adaptation. Recalculate at your new weight, increase steps, or take a 1–2 week diet break.