How do germination and purity affect seed needed?

You must plant extra seed to overcome non-germinating seed (germ %) and inert/other matter (purity %). Required seed = target plants ÷ (germ×purity).

What if I don't know seeds per pound?

Leave it blank—you’ll still get seeds per acre (or hectare). Enter seeds/lb or seeds/kg later to see pounds or kilograms required.

Not directly. Add a small reserve % to cover in-field loss, pests, or uneven depth.

Units: Saved on this device

Method

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Area input

Area

Row spacing

Row spacing ()

In-row spacing ()

Seed quality & size

Germination (%)

Purity (%)

Reserve / overplant (%)

Seeds per pound (optional)

We'll convert seeds → if provided.

Results

Target stand (): —

Seeds required (): —

Seed rate: —

Seeds for your area: —

for your area: —

Plants per 1000 of row: —

Estimates only. Calibrate your planter/drill for exact delivery.

Handy tools for weighing, sampling, and converting seed rate/density. Links open in a new tab.

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Enter spacing or target population to see the step-by-step.

Plants/ft² (row mode) = 144 ÷ (row(in) × in-row(in)) • Metric: Plants/m² ≈ 1550 ÷ (row(cm) × in-row(cm))
Plants/acre = plants/ft² × 43,560 • per hectare = × 2.47105
Effective seed fraction = (germ% × purity%) ÷ 10000
Required seeds = target plants ÷ effective × (1 + reserve%)
Pounds/acre = seeds/acre ÷ seeds-per-pound • kg/ha = lb/ac × 1.12085
Plants per 1000 ft row = 1000 ÷ (in-row spacing (ft)) • per 1000 m = 1000 ÷ spacing(m)

Prepared by AgCalculator · Estimates only. Verify before purchasing materials or operating equipment.