Field Area Acres Calculator
Know your field size to plan seed, fertilizer, and chemicals. This converts length × width into acres the standard way: 43,560 square feet per acre.
What does this tool do?
Field Area Acres Calculator computes the result directly in your browser — Know your field size to plan seed, fertilizer, and chemicals. This converts length × width into acres the standard way: 43,560 square feet per acre. Nothing you enter is uploaded or stored.
Formula: acres = (length × width in feet) ÷ 43,560. One acre = 43,560 square feet. Reference: 1/4 section = 160 acres, 1/2 section = 320, a full section = 640. Irregular fields: split into rectangles and right triangles, compute each, and sum — a triangle is ½ × base × height. Use: this feeds your fertilizer, seed, and chemical rate planning — rates are per acre.
How this calculator works
Formula: acres = (length × width in feet) ÷ 43,560. One acre = 43,560 square feet. Reference: 1/4 section = 160 acres, 1/2 section = 320, a full section = 640. Irregular fields: split into rectangles and right triangles, compute each, and sum — a triangle is ½ × base × height. Use: this feeds your fertilizer, seed, and chemical rate planning — rates are per acre.
Worked example
A quarter-mile by quarter-mile field (1,320 x 1,320 ft) is 1,742,400 sq ft = 40.00 acres (divide by 43,560).
FAQ
How many square feet are in an acre?
43,560 square feet. Multiply field length by width in feet and divide by 43,560 to get acres.
How big is an acre compared to a football field?
An acre is about 90% of a football field including both end zones, or roughly 43,560 square feet. A quarter-mile-by-quarter-mile square is 40 acres.
How do I measure an irregular field?
Break it into rectangles and triangles, measure each, and sum the areas. For very irregular boundaries, GPS or aerial mapping gives the most accurate acreage.
Figures are editable example defaults for planning, not guarantees. Crop inputs, prices, and moisture handling vary by farm, region, and year — verify with your local extension service and agronomist.