Calculate thousand seed weight, total seeds, or total weight from any two inputs using grams, kilograms, ounces, or pounds with unit conversion.
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Thousand Seed Weight Formula
The thousand seed weight calculator uses the relationship between total seed weight, total number of seeds, and the weight of 1,000 seeds.
- TSW = thousand seed weight
- W = total weight of the seed sample
- N = total number of seeds in the sample
To calculate the total number of seeds, the formula is rearranged:
To calculate the total weight, the formula is rearranged:
The calculator lets you enter any two values and solves for the missing one.
- If you enter total weight and total number of seeds, it calculates thousand seed weight.
- If you enter thousand seed weight and total weight, it estimates the total number of seeds.
- If you enter thousand seed weight and total number of seeds, it calculates total weight.
Weight values are converted to grams for the calculation, then converted back to the unit you selected.
Seed Weight Unit Conversions
These are the weight conversions used when changing between grams, kilograms, ounces, and pounds.
| Unit | Equivalent in grams | Common use |
|---|---|---|
| 1 gram | 1 g | Small seed samples |
| 1 kilogram | 1,000 g | Larger seed lots |
| 1 ounce | 28.3495 g | Imperial weight measurements |
| 1 pound | 453.592 g | Bulk seed weight |
Typical Thousand Seed Weight Ranges
Thousand seed weight varies by crop, variety, moisture level, and seed quality. These ranges are only general references.
| Seed type | Typical TSW range | Unit |
|---|---|---|
| Canola / rapeseed | 3 to 6 | g per 1,000 seeds |
| Wheat | 30 to 45 | g per 1,000 seeds |
| Barley | 35 to 50 | g per 1,000 seeds |
| Soybean | 120 to 200 | g per 1,000 seeds |
| Corn / maize | 250 to 400 | g per 1,000 seeds |
Examples
Example 1: Calculate thousand seed weight
You count 500 seeds and the total weight is 20 g.
The thousand seed weight is 40 g per 1,000 seeds.
Example 2: Calculate total number of seeds
You have 2 kg of seed. The thousand seed weight is 40 g.
First convert 2 kg to grams:
Then calculate the number of seeds:
The estimated total number of seeds is 50,000 seeds.
FAQs
What does thousand seed weight mean?
Thousand seed weight is the weight of 1,000 seeds from a seed lot. It is often used to compare seed size, estimate seed counts, and calculate planting rates.
Does seed moisture affect thousand seed weight?
Yes. Wetter seeds weigh more than drier seeds. If you compare two seed lots, the moisture level should be similar. Otherwise, the difference in thousand seed weight may partly come from water content instead of seed size.
How many seeds should you count for a sample?
You can calculate thousand seed weight from any counted sample, such as 100, 250, 500, or 1,000 seeds. A larger counted sample usually gives a more reliable result because it reduces the effect of individual seed variation.
