Seed Quantity Calculator

Calculate how many seeds you need, how many seed packets to buy, expected germination, seed weight, coverage area, and total seed cost. Use this seed quantity calculator for gardens, raised beds, flower beds, native seedings, row planting, seed trays, and small field plots.

Calculate Seed Quantity

Seeds to Buy = Base Seeds × (1 + Extra Seed Allowance).
Your result will appear here.

How the seed quantity calculator works

Seeds from area:
The calculator uses planting area, seed spacing, row spacing, and seeds per spot to estimate base seed quantity.

Seeds from planting spots:
Enter known planting spots or holes and seeds per spot to estimate how many seeds are needed.

Seeds from target plants:
Enter a target plant count and the calculator adjusts for germination and survival rates to estimate how many seeds to plant.

Packets and cost:
The calculator estimates seed packets, seed ounces, packet cost, ounce cost, and total seed cost.

Why use a seed quantity calculator?

A seed quantity calculator helps estimate how much seed to buy before planting a garden, tray, bed, row, or small plot.

It can be useful for vegetables, herbs, flowers, native plantings, direct seeding, seed trays, raised beds, school gardens, and small field plantings.

What your result means

Your result shows base seeds needed, adjusted seeds to buy, expected germinated seeds, expected surviving seedlings, seed packets needed, seed ounces needed, packet cost, bulk seed cost, and total seed cost. These are planning estimates based on your spacing, germination rate, survival rate, and extra seed allowance.

Seed quantity formulas

Frequently asked questions

How do I calculate how many seeds I need?

Estimate the number of planting spots, multiply by seeds per spot, then add extra seed for germination loss, thinning, damage, and reseeding.

Why does germination rate matter?

Not every seed sprouts. Germination rate helps estimate how many seeds may become seedlings and whether more seed is needed.

How many seed packets should I buy?

Divide the seeds you need to buy by the number of seeds per packet, then round up to the next full packet.

Should I buy extra seeds?

Yes. Buying extra seed helps cover poor germination, thinning, planting mistakes, pests, weather damage, and reseeding needs.