Seed Rate Calculator
The seed-rate calculator estimates a sowing quantity after adjusting a target pure-live-seed rate for germination and physical purity.
How to use this calculator
- Enter area, target pure-live-seed rate, germination percentage and purity percentage.
- Check the units and definitions before comparing results with another source.
- Change one input at a time when comparing scenarios, and keep the reporting period and assumptions consistent.
Formula used by the seed rate calculator
Adjusted seed mass = area × target rate ÷ (germination fraction × purity fraction)
- Adjusted seed mass = area × target rate ÷ (germination fraction × purity fraction)
- Use a target rate suitable for the species, season and method. Germination and purity should come from a representative label or test.
- Inputs are checked for required values and valid ranges; displayed results are rounded for readability.
Worked examples
Worked example
Seed 100 m² at 3 g/m² with 90% germination and 98% purity.
The pure-live-seed target is 300 g; adjustment gives about 340.14 g of supplied seed.
The pure-live-seed target is 300 g; adjustment gives about 340.14 g of supplied seed.
Understanding the result
The seed-rate calculator estimates a sowing quantity after adjusting a target pure-live-seed rate for germination and physical purity.
Use a target rate suitable for the species, season and method. Germination and purity should come from a representative label or test.
Important notes
Use a target rate suitable for the species, season and method. Germination and purity should come from a representative label or test.
The result applies to the numbers and assumptions entered here; verify specifications for safety-critical or regulated uses.
Frequently asked questions
Why adjust for germination?
Some seeds may not germinate, so the adjusted quantity accounts for the supplied germination fraction.
Does a higher seed rate always improve results?
No. Over-sowing can waste seed or create competition; follow species-specific recommendations.
How do I use this calculator?
Enter area, target pure-live-seed rate, germination percentage and purity percentage.
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This page provides a calculation tool plus explanatory information so you can understand what the result means and when the underlying method may not fit your situation.