Garden Calculators
Use these free gardening calculators to estimate seeds, plant spacing, watering, soil volume, mulch, and other garden inputs before you plant or purchase supplies.
Planting
How many seeds to buy, and how many plants actually fit.
Seed Calculator
Work out how many seeds to buy and sow from your bed size, spacing, germination rate, and seeds per hole.
Calculate Seeds →Learn the math: How to Build Your Own Vegetable Seed Calculator
Plant Spacing Calculator
Turn bed dimensions and a crop spacing into rows, plants per row, and a total plant count — square grid or offset.
Calculate Spacing →Learn the math: The Plant Spacing Formula Behind Every Seed Packet
Soil & Beds
How much soil and mulch to order for your beds.
Soil Calculator
Calculate how many cubic feet or cubic yards of soil you need for raised beds and garden containers.
Calculate Soil →Learn the math: How Much Soil You Need for a Raised Bed (With Formula)
Mulch Calculator
Estimate cubic feet, cubic yards, and bags of mulch for any bed from its size and your chosen depth.
Calculate Mulch →Learn the math: How to Calculate Exactly How Much Mulch You Need
Watering
How often to water, how many gallons, and how long to run drip.
Watering Calculator
Get a weekly watering frequency, gallons per week for your bed, and optional drip run times.
Calculate Watering →Learn the math: Water Needs Per Plant: A Practical Reference
Want All the Formulas in One Place?
The free Garden Math guide collects the math behind every calculator, with worked examples and planning worksheets.
Get the Free Garden Math Guide