Harvest and weigh a measured piece of the field, enter its area and the size of the whole parcel, and read the yield in tonnes per hectare along with the total harvest. Add the harvest moisture and the moisture yields are quoted at and you also get the corrected figure — the one comparable with published averages.
What you actually weighed off the measured piece.
For rows: metres harvested × row spacing in metres.
Enter the sample weight, the sample area and the field area.
How it works
Yield per hectare is the sample mass divided by the sample area, multiplied by 10,000. A 10 m² strip that gives 8.5 kg is 8,500 kg/ha, or 8.5 t/ha. The whole-field figure is then that rate times the field area in hectares, so the accuracy of the result rests entirely on how honestly the sample represents the field.
Published yields always refer to a standard moisture — around 14% for maize and wheat. If your sample was weighed at 20% moisture, part of what you weighed is water that will leave in the dryer. The correction uses the same relation as the drying-shrink tool: mass × (100 − harvest moisture) ÷ (100 − standard moisture), so 8.5 t/ha at 20% becomes 7.91 t/ha at 14%.
Sample size is the practical limit. One small strip in a good patch flatters the field; several samples across it, averaged, do not. For row crops a common approach is to harvest a few metres of row and convert with the row spacing; for cereals a square frame of a known area is easier. Enter the sample in grams or kilograms and the field in square metres, ari or hectares.
Practical examples
A maize strip of 10 m²
8.5 kg off 10 m² is 8.5 t/ha. On a 4-hectare parcel that projects to 34 tonnes at the moisture it was weighed at.
The same sample corrected to 14%
If the grain was at 20% moisture, the comparable yield is 7.91 t/ha — 0.59 t/ha lower — and the field total drops to about 31.6 tonnes.
A cereal frame of 1 m²
A 450 g sample from a 1 m² frame is 4.5 t/ha. Frames are quick, which is the point: take five of them across the field and average before trusting the number.
A vegetable bed
3.2 kg from 2 m² of a tomato bed is 16 t/ha; for a 250 m² bed that is 400 kg — the kind of figure worth knowing before planning next season’s planting.
Frequently asked questions
How large should the sample be?
Large enough to average out gaps and good spots: 1 m² frames for cereals, several metres of row for maize or sunflower. More important than size is taking several samples across the field and averaging them.
How do I turn metres of row into an area?
Multiply the row length harvested by the row spacing in metres. Five metres of row at 70 cm spacing is 3.5 m² — enter that as the sample area.
Why correct for moisture at all?
Because water is not yield. A sample at 20% moisture weighs more than the same grain will after drying, so comparing it against published averages quoted at 14% overstates your result by around 7%.
What standard moisture should I use?
The one your buyer or statistics office uses — commonly 14% for maize and wheat, 9% for sunflower. The tool asks instead of assuming because contracts differ.
Can I skip the moisture fields?
Yes. Leave both empty and you get the as-harvested yield. If you fill in only one, the tool asks for the other, because a single moisture figure cannot define a correction.
Does it account for harvest losses?
No. Grain left on the ground by the combine, or a hand sample gathered more carefully than a machine would, both inflate the estimate. A pre-harvest sample is usually optimistic compared with what crosses the weighbridge.
Can I use it to estimate yield before harvest?
For a rough figure, yes — hand-harvest and thresh a measured strip. Expect it to read a few percent high because a machine loses more than your hands do.
How does this relate to counting ears or plants?
Ear-count methods estimate yield from plants per hectare, grains per ear and grain weight. They are useful earlier in the season, while weighing a real sample is more direct and less dependent on assumed grain size.
Can I compare two parts of the same field?
Yes, and it is one of the better uses: sample each zone separately and enter its own area. Differences of a tonne per hectare across one parcel are common and often explain a soil or drainage problem.
Does it convert to bushels per acre?
No — the tool works in metric units used here. Bushel conversions depend on the crop’s test weight, which is a separate figure entirely.
Are decimal commas and small areas supported?
Yes. Both 3,2 and 3.2 are read the same way, and field areas can be entered in square metres, ari or hectares.
Is my data uploaded?
No. Everything is computed in your browser and stays there.
Related tools
Seed Rate Calculator
Seeding rate in kg/ha from target plant density, thousand-seed weight, germination and purity.
Agriculture & garden
Plant Spacing Calculator
How many plants fit your plot at a given row and in-row spacing, with density per m² and per hectare.
Agriculture & garden
Land Unit Converter
Convert jutro, lanac, square fathoms, dunums, ari and hectares — the land measures still used in listings.
Agriculture & garden
Grain Moisture Shrink Calculator
What a wet lot weighs after drying to the moisture you are paid at, with the water removed and the shrink percentage.
Agriculture & garden
Irrigation Water Calculator
Water needed for an irrigation depth in litres and m³, plus the run time from drip or sprinkler rate.
Agriculture & garden
Fertilizer Calculator
Turn a kg/ha nutrient target and an NPK grade into the fertilizer rate, total kilograms and bag count.
Agriculture & garden