Harvest Estimate

Free Harvest Estimate calculator with clear step-by-step results.

About Harvest Estimate

Uses the standard yield components method: plants per square metre, heads per plant, grains per head and thousand grain weight multiply out to a mass per square metre, which scales to tonnes per hectare. Harvest and handling losses are then deducted to give what actually reaches the store.

Formulas

Yield per square metre

g/m2 = plants x heads per plant x grains per head x TGW / 1000

Yield per hectare

t/ha = g/m2 x 10,000 / 1,000,000

Worked example

With the default values below, Harvest Estimate returns Expected harvest of 49.61. Change any input above and every figure here is recalculated in your browser.

Inputs used

Cropped areaminimum 0.01 ha: 12 ha
Plant populationminimum 0.1 plants/m2: 220 plants/m2
Heads or pods per plantminimum 0.1: 1.4
Grains per headminimum 0.1: 34
Thousand grain weightminimum 1 g: 42 g
Harvest and handling lossaccepts 0–40 %: 6 %

Results

Expected harvest: 49.61 t
Gross yield: 4.398 t/ha
Net yield after losses: 4.134 t/ha
Grains per square metre: 10,472

Step by step

1Values used
2Yield per square metre
3Yield per hectare
4Expected harvest= 49.61 t
5Gross yield= 4.398 t/ha
6Net yield after losses= 4.134 t/ha
7Grains per square metre= 10,472

Assumptions and limits

The result is derived only from the 6 inputs listed above. Anything not among them is not part of the calculation.
In particular, this calculator does not take inflation, tax, fees or charges or compounding frequency into account.
Figures are rounded for display to 3 decimal places, so totals built from several rounded parts can differ slightly from the unrounded arithmetic.

How these calculators are built and tested is described on the Methodology page. If a figure looks wrong, please report it.

Frequently Asked Questions

How do I count grains per head accurately?

Sample at least twenty heads from several representative points in the field, avoiding headlands and tramlines. Grain number is the most variable of the four components.

When is this estimate reliable?

Once grain fill is complete, roughly at soft dough stage. Earlier estimates have to guess thousand grain weight, which can swing 20% with late-season stress.