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.

Grow a Garden updates often — sometimes more than once a week. Here’s every value refresh, new tool, and fix we’ve shipped, newest first.

July 22, 2026New

July 20, 2026New

Added the Pet Ability Calculator with cooldown-by-age scaling and a 48-pet ability database.
Added the Egg Hatch Calculator covering 18 eggs with hatch times, prices and pet probabilities.

July 18, 2026Updated

July 15, 2026New

Launched the Pet Calculator (weight by age + value) and Pet XP Calculator.
Expanded the Mutation Calculator to 190+ mutations with a stack tester and “how to get it” for each.

July 12, 2026New

GardenValueCalc went live with the plant value calculator, weight & mutation system and friend boost.

Spotted a value that changed after an update? Let us know — community reports keep this calculator accurate.