Agriculture
Seed Rate Calculator
Calculate viable seeds required per square metre, total seed count, kilograms per hectare, total seed mass, whole bags, and expected established plants. The custom field visual separates laboratory germination loss from field establishment loss.
Total seed required-
Seeds to sow per m2-
Seed rate (kg per ha)-
Total seeds to sow-
Seed bags required-
Expected established plants-
Decision view
Seed-to-established-stand pathway
Seed-to-established-stand pathwayMetered seed passes through separate germination and field-establishment gates before the target stand is reached.
Exact scenario comparisonLaboratory germination (%) changes while all other entered assumptions remain constant.
| Laboratory germination (%) | Total seed required | Seeds to sow per m2 | Seed rate (kg per ha) | Total seeds to sow | Seed bags required | Expected established plants |
|---|
How to use Seed Rate Calculator
- Set the agronomic target population for crop, variety, row spacing, date, and field conditions.
- Use current lot germination and a defensible field-establishment assumption.
- Calibrate the drill with seed mass and operating conditions, then verify emergence in the field.
Calculator guide
Understanding Seed Rate Calculator
A target stand is not the same as a sowing rate. Germination and field establishment losses must be grossed up before seed count is converted to kilograms with thousand-seed weight and then to whole bags.
Calculation method
How the calculation works
Gross up the target established plant population for entered germination and field establishment, then convert seed count using thousand-seed weight. Divide target plants by germination and establishment fractions, multiply by area for total seeds, convert count with thousand-seed weight, and round bag count upward.
Stand establishment
Trace the population through each biological gate
The field diagram shows why target plants cannot be entered directly as seed count.
Worked situations
Practical examples
- A 250 plants/m² target with 92% germination and 85% establishment requires about 320 viable seeds/m² to be sown.
- A 40 g thousand-seed weight converts one million seeds to about 40 kg.
- Bag count rounds upward because a partial requirement generally requires purchasing a whole bag.
Better inputs
Useful tips
- Use the seed certificate for the exact lot rather than a generic germination value.
- Adjust establishment for seedbed, depth, moisture, pests, residue, weather, and equipment.
- Recalibrate when thousand-seed weight or product treatment changes.
Before relying on the result
Limitations and common mistakes
- Emergence is represented by one constant establishment percentage.
- Row spacing, seeds per metre, drill slippage, overlap, headlands, field shape, seed coating, purity, mortality after emergence, and replant decisions are excluded.
- Agronomic targets should come from local crop guidance.
Reference
Key terms
- Target stand
- Desired established plants per unit ground area.
- Germination
- Laboratory-tested share of seed expected to germinate.
- Establishment
- Share of germinated seed expected to become established field plants.
- Thousand-seed weight
- Mass of one thousand seeds from the entered lot.
Important note
Calculated from the entered field and production values. Confirm seed-lot data, equipment calibration, labels, local conditions, and applicable agronomic guidance.
Frequently asked questions
Why divide by germination instead of multiply?
More seed must be sown so the surviving share reaches the target.
Why does thousand-seed weight matter?
Two lots can need the same seed count but different kilograms.
Should bag count be rounded?
The calculator rounds the purchase requirement upward to whole bags.
Does this replace drill calibration?
No. Mechanical delivery must be checked with the actual seed lot and field setup.