AgricultureID

Calculator · planting

Seed-rate calculator

Estimate seeds to sow from a target plant population, germination, and field establishment — and a seed rate in kg/ha if a thousand-seed weight is given.

Required

Leave blank to get seeds/m² only.

Result

Enter values to see a result.

Formula & assumptions

Seed rate (seeds per m²) from target population

formula v1.0.0 · calc v1 · reviewed 2026-07-12

seeds/m² = target_plants/m² ÷ (germination% ÷ 100 × establishment% ÷ 100)

Applies to: Field and row crops sown to a target plant population.

Assumptions

  • Establishment percentage captures field losses beyond laboratory germination.

Limitations

  • A field-adjusted estimate, not a guaranteed stand; local conditions dominate.

Sources: Penn State Extension, The Pennsylvania State University (opens in a new tab), Agriculture and Horticulture Development Board (AHDB) (opens in a new tab)

Seed rate (kg/ha) from seeds/m² and thousand-seed weight

formula v1.0.0 · calc v1 · reviewed 2026-07-12

seed_rate (kg/ha) = seeds/m² × thousand_seed_weight_g ÷ 100

Applies to: Crops with a known thousand-seed (or thousand-grain) weight.

Assumptions

  • Thousand-seed weight is the mass of 1000 seeds in grams.

Limitations

  • Thousand-seed weight varies by lot; use the tested value on the label.

Sources: Agriculture and Horticulture Development Board (AHDB) (opens in a new tab), Penn State Extension, The Pennsylvania State University (opens in a new tab)

About this tool

  • The field-adjusted seed rate is an estimate, not a guaranteed stand. Local seedbed, moisture, pests, and sowing quality dominate the outcome — not a universal figure.

Educational reference — not a prescription

  • These calculators are for education and reference. The quality of any result depends entirely on the accuracy of the values you enter.
  • Local agronomic conditions, legal requirements, product labels, and professional advice may override a general calculation.
  • Results are not pesticide, fertilizer, irrigation, or veterinary prescriptions, and are not a substitute for advice from a qualified agronomist or your local extension service.