Part of the Agriculture collection — 4 tools available
Field Area Calculator — Acres from Dimensions
Calculate acreage from length and width measurements. Convert square feet, square meters, and hectares to acres for field and pasture planning.
About This Calculator
Accurate field measurements are the foundation of every farming decision — from seeding rates and fertilizer applications to chemical spray calculations and lease payment agreements. One acre equals 43,560 square feet, but most fields aren't perfect rectangles, and converting between acres, hectares, and square meters trips up even experienced farmers when precision matters. Applying chemicals to an inaccurately measured field means either wasting product on too many acres or under-applying on too few. Our field area calculator converts your length and width measurements into acres, hectares, and square meters for quick reference.
The Formula Behind This Calculator
Rectangle: L * W Triangle: 0.5 * Base * Height Circle: pi * R² Irregular: Sum of simple shapes.
Understanding the math helps you verify results and make better decisions for your project.
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How to Use
- 1Measure the field length in feet using a measuring wheel, GPS, or mapping tool.
- 2Measure the field width in feet.
- 3Review the calculated acreage, hectares, and square meters.
When to Use
- →Determining acreage for seed, fertilizer, and chemical calculations.
- →Calculating land lease payments based on per-acre rates.
- →Planning field layouts and crop rotations for the season.
Tips
- ✓For irregular fields, break them into rectangles and triangles, calculate each separately, then sum.
- ✓One acre is roughly 208.7 feet on each side of a square, or one American football field minus the end zones.
- ✓Use GPS mapping apps like John Deere Operations Center for the most accurate irregular field measurements.
FAQ
How many square feet are in an acre?
One acre equals exactly 43,560 square feet. It's also 4,047 square meters, 0.4047 hectares, or about 90% of an American football field.
How do I measure an irregularly shaped field?
Break the field into simple shapes (rectangles and triangles), measure each, calculate area separately, then add them together. GPS tools and aerial maps make this much easier.
What's the difference between a US acre and a hectare?
One hectare equals 2.471 acres. Hectares are used in metric countries. An acre originated as the area one ox could plow in one day.
Related Calculators
Fertilizer Calculator — NPK Application Rate
Calculate how much fertilizer to apply based on NPK ratio, target nitrogen rate, and field size. Get accurate pounds per acre and total product needed.
Seed Rate Calculator
Calculate how many seeds or pounds of seed you need per acre based on plant spacing, germination rate, and target population for your field.
Irrigation Calculator — Gallons Per Hour
Calculate water requirements for your field or garden. Estimate gallons per hour, daily volume, and total water based on area and application depth.