Agriculture Calculators

Farm-planning math from the field to the bin: cost per bushel, grain shrink and drying, bin capacity, feed efficiency, fertilizer rates, and growing degree days — with editable example inputs and honest sourcing.

Agriculture

Break-Even Cost per Bushel Calculator

Find your break-even cost per bushel from total production costs and expected yield — the price you need ...

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Grain Storage & Drying Cost Calculator

Estimate grain shrink from field-moisture drying, drying charges, and interest on stored grain — the Purd...

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Grain Bin Capacity Calculator

Estimate how many bushels a round grain bin holds from diameter, eave height, and peaked roof — using the...

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Feed Conversion Ratio Calculator

Calculate feed conversion ratio (FCR) and cost of gain for livestock — feed consumed vs weight gained, an...

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Fertilizer Rate Calculator

Convert a nutrient recommendation (lb N-P-K per acre) into the pounds of actual fertilizer product needed...

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Growing Degree Day Calculator

Track growing degree days (GDD) for crop development — the daily heat accumulation that drives corn and c...

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Field Area Acres Calculator

Convert field length and width into acres for square or rectangular fields, with a triangle method for od...

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How to choose

How to choose an agriculture calculator

Pick by decision, not by category. Buying seed? Seeding rate and plant population calculators convert your row spacing and target stand. Planning fertility? The fertilizer calculators turn a soil-test recommendation into product quantity. Pricing harvest? Yield and grain tools convert moisture and bushel weights. Each page opens with the formula and an editable example.

The math

How these calculators work

Agronomic calculators here use the standard extension-service formulas — plants per acre from row spacing and in-row spacing, nutrient application from analysis and target pounds, yield from harvest counts and moisture corrections. Sources for each method are linked on the page.

Honest limits

What these tools do not do

These calculators do not replace a soil test, an agronomist, or a crop insurance appraisal. They make the standard arithmetic transparent so you can check any recommendation you are handed.

Quick answers

Common questions

How do I calculate seeding rate per acre?

Target population divided by germination rate, adjusted for row spacing. The seeding rate calculator does both steps and shows the intermediate numbers so you can audit the result.

How much fertilizer do I need for a given field?

Convert the soil-test recommendation (pounds of N, P, K per acre) into product pounds using the bag's analysis grade. The fertilizer calculator handles the conversion for any grade you enter.

How is grain yield estimated before harvest?

The classic yield-component method: ears per acre, kernels per ear, and kernels per bushel. The yield estimator walks each factor with your field counts.

Do the calculators handle metric units?

Several do, and the rest can be worked by converting your inputs first — unit handling is stated on each tool page so there is no ambiguity about which units it expects.

Can I trust the agronomic defaults?

Treat every default as a starting point. Regional recommendations differ; your extension service's local guidance should override any generic default here.

Worked example: soil test to bag pounds

Take a soil test calling for 120 lb N, 60 lb P2O5, and 90 lb K2O per acre, and three tags on the shelf: urea 46-0-0, DAP 11-52-0, potash 0-0-60. Divide each target by its analysis. 120 / 0.46 = 260.9 lb urea per acre. 60 / 0.52 = 115.4 lb DAP. 90 / 0.60 = 150.0 lb potash. Stacked, that is 526.3 lb of product per acre, or 63,156 lb (31.6 tons) across 120 acres.

The catch is the DAP grade. At 18% N it rides 115.4 x 0.18 = 20.8 lb of nitrogen in on top of the 120 the test asked for, a 17.3% overshoot. Back the urea out: (120 - 20.8) / 0.46 = 215.7 lb per acre. The corrected blend is 215.7 + 115.4 + 150.0 = 481.1 lb per acre, 57,732 lb (28.9 tons) for the field, and delivered N lands on 120.0. Check every recommendation this way: pounds of product times analysis equals pounds of nutrient.

Caps, floors, and the zero case

Seeding rate divides by germination, so the edges decide whether the number means anything. A 32,000 plant target costs 33,684 seeds at 95% germination (1.053 seeds per plant) and 40,000 seeds at 80% (1.25 per plant). At 100% the two figures meet at 32,000. At 0% the rate is undefined, not infinite, and any tool that hands back a number there is wrong. Seed tags stop at 100%, so 105% is not a real input; use the tested figure off the bag.

Temperature tools cap and floor for the same reason. On a 95F/72F day, raw average minus 50 returns 33.5 growing degrees, but capping the high at corn's 86F ceiling gives (86 + 72) / 2 - 50 = 29, so the uncapped path runs 15.5% hot. On a 45F/38F night the raw math returns -8.5, and a floored day returns 0. Season totals built from uncapped days accumulate that drift daily, and the maturity date predicted from them can land a week early.