Free Garden Calculators That Give You a Straight Answer

Every tool takes your numbers and returns exactly what to buy, sow, or plant — nothing else.

Raised Bed Soil Calculator

Exact cubic feet, bags needed, and cost estimate for any bed size or mix recipe.

Seed Starting Calculator

Count back from your last frost date to find the right indoor sowing week.

Plant Spacing Calculator

Get exact row and in-row spacing for any crop in any bed size.

Succession Planting Calculator

Schedule repeat sowings so you always have something ready to harvest.

Germination Rate Calculator

Turn a germination test into exact seed quantities to sow.

Compost Ratio Calculator

Balance browns and greens to hit the right C:N ratio for fast decomposition.

Why RootCalcs?

Every formula is documented and explained on the calculator page. You can verify the arithmetic yourself.

No account, no email wall, no paywall. Open the calculator, enter your numbers, get your answer.

Designed for a small screen with one hand free. Fast, readable, zero distractions.

Get the free planting-day checklist

Everything you need before seeds go in the ground — sent once, no spam.