When an old packet or an unfamiliar seed lot is part of the sowing plan, a counted sample gives you something more concrete than an assumed percentage. Record how many seeds were included and how many germinated under your test conditions.
The Seed Germination Test Calculator calculates that observed percentage. It also shows how many seeds did not germinate and estimates a future sowing count for a chosen germinated seedling target. The result describes the sample, not the performance of every remaining seed in the packet.
Thirty four germinated seeds out of forty
If 40 seeds were tested and 34 germinated, the observed germination is 85%. Six seeds in that sample did not germinate. A target of 100 germinated seedlings at the same observed rate requires 100 divided by 0.85, or about 117.647 seeds, rounded up to 118.
That planning count does not include losses after germination. It is also not an instruction to sow a partial seed. The decimal belongs to the arithmetic before the calculator rounds to a whole sowing count.
Count a consistent outcome
Use a clear definition of what you counted as germinated and apply it to the whole sample. Record the date and conditions separately if you want to compare the result with another test later. Changing the counting standard between tests can make the percentages look different even when the seed lot has not changed.
Do not enter more germinated seeds than the total tested. The calculator rejects that combination because it cannot represent this sample percentage. It accepts zero germinated seeds, but then reports no finite seed count for a positive future target at the observed rate.
A small sample can vary from the rest of the packet. The tool does not calculate a confidence interval or promise that sowing 118 seeds will give precisely 100 seedlings. Treat the result as a planning observation with the sample size attached.
Decide what to do with the number
An observed percentage may support a revised order, another test or a decision to use a different lot. It does not diagnose whether poor results came from the seeds, test conditions or handling. That needs observation outside a two number calculation.
For an established plant target rather than a germinated seedling target, use Seed Quantity Calculator and enter survival after germination separately. If you are sowing into cells, Seed Tray Planner can allocate the positions and medium. Keep the observed sample rate available, but do not mistake it for a measured usable transplant rate unless your records actually cover that later stage.