GIFSQ Tools · Module 5 — Cereal, Grain, Flour & Milling Technology · Tool 83 of 500
Thousand-kernel weight (TKW) from a counted sample, with kernels per kilogram and an optional seeding rate from the target plant density and germination.
Try sample values — fills the form with the worked example below.
Seeding rate (optional)
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Thousand-kernel weight (g)
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Kernels per kg
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Seeding rate (kg/ha)
Equation: Thousand-kernel weight (g) = mass of counted kernels (g) ÷ kernels counted × 1,000. Kernels per kg = 1,000,000 ÷ thousand-kernel weight. Seeding rate (kg/ha) = target plants per m² × thousand-kernel weight ÷ 100 ÷ germination (as a fraction).
Method: Thousand-kernel weight is the standard grain-size measure in cereal grading and seed testing (ISTA rules count 8 replicates of 100 kernels; a single count of 250 kernels is the routine field shortcut). Seeding rate follows the standard agronomy mass balance for the target stand.
Assumptions: the counted kernels represent the lot; each kernel weighs the lot average; germination is the laboratory germination percentage.
Limitations: a small count (under 100 kernels) is noisy; shrivelled or broken kernels bias the mean low; the seeding rate does not allow for field emergence losses beyond germination.
Rounding: thousand-kernel weight to 2 decimal places; kernels per kilogram to 2 decimal places; seeding rate to 2 decimal places. Intermediate values are not rounded.
This is a calculation aid, not a laboratory report — confirm against your accredited method before citing a value.
Method: Thousand-kernel weight is the standard grain-size measure in cereal grading and seed testing (ISTA rules count 8 replicates of 100 kernels; a single count of 250 kernels is the routine field shortcut). Seeding rate follows the standard agronomy mass balance for the target stand.
Assumptions: the counted kernels represent the lot; each kernel weighs the lot average; germination is the laboratory germination percentage.
Limitations: a small count (under 100 kernels) is noisy; shrivelled or broken kernels bias the mean low; the seeding rate does not allow for field emergence losses beyond germination.
Rounding: thousand-kernel weight to 2 decimal places; kernels per kilogram to 2 decimal places; seeding rate to 2 decimal places. Intermediate values are not rounded.
This is a calculation aid, not a laboratory report — confirm against your accredited method before citing a value.
Worked example: 250 kernels weigh 8.75 g. Thousand-kernel weight = 8.75 ÷ 250 × 1,000 = 35.00 g; kernels per kg = 1,000,000 ÷ 35 = 28,571.43. At 250 plants per m² and 95 % germination the seeding rate = 250 × 35 ÷ 100 ÷ 0.95 = 92.11 kg/ha.
Enter values above to see results.
Typical wheat thousand-kernel weight is 30–45 g; barley 35–50 g; canola about 4–6 g. Count at least 250 kernels for a stable result. Tool 83 of 500 — GIFSQ Tool 83 of 500 — GIFSQ
