Count what germinated, calculate the observed percentage, estimate how many seeds to sow for a target number of seedlings and save repeat tests so seed lots can be compared with your own evidence.
The result is observed germination rate: germinated seeds ÷ seeds sown × 100. Save repeat batches to compare your own seed lots and conditions over time.
Batch history stays in this browser and is intended for your own comparisons, not as a universal germination standard.
Divide the number of seeds that germinated by the number originally sown, then multiply by 100. If 16 of 20 seeds germinate, the observed rate is 16 ÷ 20 × 100 = 80%.
The calculator deliberately calls this an observed rate rather than a quality score. Different species, seed ages, storage histories, temperatures, moisture levels and test durations can all affect the result.
If the observed rate is 80% and you want 40 seedlings, the germination-only estimate is 40 ÷ 0.80 = 50 seeds to sow. The tool performs that conversion automatically from the current test result.
This is not a transplant-survival prediction. Damage, damping-off, thinning, transplant shock and later growing conditions can still reduce the number of usable plants after germination, so add any separate survival margin you personally need.
A single tiny sample can be misleading. Repeating a test with the same crop or seed lot builds a stronger personal baseline, especially for older seed packets. The tracker therefore keeps batch history locally and shows a weighted observed rate across matching saved tests.
For a practical test, use a sample large enough to be useful, keep the conditions as consistent as possible, and note temperature, medium, pre-soaking or other factors that might explain differences.