Acres to Square Meters Converter

1 acre is exactly 4,046.8564224 m², or 43,560 square feet

The National Institute of Standards and Technology (NIST) defines 1 acre as 43,560 square feet. The international foot is exactly 0.3048 m, so 1 square foot is 0.09290304 m², and 43,560 × 0.09290304 = 4,046.8564224 m², a value fixed to the last digit. In hectares that is exactly 0.40468564224 ha. An acre is also 4,840 square yards, and as a square it measures about 208.71 ft (63.61 m) on each side.

The converter above keeps five fields in step: acres, square meters, hectares, square feet and square yards. Type a number into the field that matches your source and that field becomes the reference; the others show the converted value rounded to the decimals you pick. If you only know the dimensions of a lot, switch to "Length × width", choose ft or m and enter both sides. The plan on the right draws your land, a 1-acre square and an American football field at the same scale, so an abstract number becomes something you can see.

When you need to read an acre in feet or meters

• Lot dimensions in feet: house plots are often described as 100 × 200 ft or 50 × 100 ft rather than by area. Multiply the two sides to get square feet and divide by 43,560 to get acres. The "Length × width" mode does that and gives square meters as well.
• Metric figures against an acre: a hectare, 1,000 m² or a 100 m × 100 m square is easy to mistake for an acre. A 100 m × 100 m square is 1 hectare, which is 2.4711 acres, and 1,000 m² is only 0.2471 acres.
• 40, 160 and 640 acres: the U.S. Public Land Survey System (PLSS) divides land into townships of 36 sections, each nominally one mile square and 640 acres. A quarter section is 160 acres and a quarter-quarter section is about 40 acres, which is why those round numbers keep appearing in listings and deeds. The tables below convert them.
• Farm and ranch statistics: the USDA's 2022 Census of Agriculture counted 1.9 million farms and ranches with an average size of 463 acres. That is about 1,873,695 m², or 1.87 km², the area of a square roughly 1.37 km on a side.
• Acres in UK law: Schedule 1 of the Weights and Measures Act 1985 defines the acre as 4,840 square yards and 1 square mile as 640 acres. It lists the acre in Part VI, among units that may be used for trade only as a supplementary indication, while the hectare (100 ares) sits in Part II.

How to use it

1. Type a number into the field for the unit in your source: acres, square meters, hectares, square feet or square yards. The field you edited last is the reference and gets the stronger border. Thousands separators such as 1,234.5 work, and so do fractions such as 1/4 or 1 1/2.
2. If you only know the sides, pick "Length × width", choose the length unit (m or ft) and enter both sides. All five area fields update together; typing in an area field takes you back to area mode.
3. Pick the decimals (0, 1, 2, 4 or 6) to round the fields and the common values. The result sentence shows the full exact value when the decimal ends, at least six places when it does not, and puts "≈" in front of any rounded figure.
4. "See it on a plan" draws your land (the filled rectangle), a 1-acre square (dashed) and an American football field (thin line) to one scale, anchored in the lower-left corner. The bar underneath is the scale. If your land is so large that a reference shape would shrink below a dot, the legend adds "too small at this scale".
5. "Common values" fills the fields above with one tap. "Copy result" copies the result sentence and the five unit values, and "Copy link" copies an address that carries the current value.

How the conversion works

1. 1 foot is exactly 0.3048 m, so 1 square foot is 0.3048 × 0.3048 = 0.09290304 m².
2. 1 acre is 43,560 square feet. The NIST table gives the same area as 160 square rods or 10 square chains, and the UK Act defines it as 4,840 square yards. A strip 1 chain (66 ft) wide and 1 furlong (660 ft) long is exactly 43,560 square feet.
3. To go from acres to m², multiply by 4,046.8564224; to go from m² to acres, divide by the same number. Multiplying ends in a finite decimal, while dividing does not: 1 m² = 0.000247105… acres, so that direction is rounded.
4. 1 hectare is 10,000 m² (and 100 ares). To turn hectares into acres, multiply by 10,000 and divide by 4,046.8564224 (1 ha ≈ 2.471054 acres); the other way, 1 acre is exactly 0.40468564224 ha.
5. For length × width, multiply the two sides, then divide by 43,560 if you measured in feet or by 4,046.8564224 if you measured in meters. For example, 100 ft × 200 ft = 20,000 ft², and 20,000 ÷ 43,560 = 0.459137 acres.

Acres to square feet, square meters and hectares

How big is an acre?

As a square, 1 acre is about 208.71 ft (63.61 m) on a side. An American football field including both end zones (360 × 160 ft) covers 1.3223 acres, so 1 acre is about three quarters of it. A FIFA-recommended pitch of 105 × 68 m is bigger still, at 1.7643 acres. On the plan, the dashed 1-acre square sits inside both outlines.

Lot dimensions in acres

Property descriptions often give only the sides. The table turns common dimensions into area. A 100 × 200 ft lot is 0.4591 acres, 200 × 200 ft falls just short of an acre at 0.9183, and 400 × 400 ft is 3.6731 acres, not one. A square close to 1 acre measures about 208.71 × 208.71 ft.

Common mistakes

• Treating 1 acre as 100 m² or 1,000 m²: 1 acre is 4,046.86 m². 100 m² is one are (0.01 hectare), and 1,000 m² is only 0.2471 acres. The nearest round metric figure to an acre is about 4,047 m².
• Treating a 100 m × 100 m square as an acre: it is 1 hectare, or 2.4711 acres. A 200 m × 200 m square is 9.8842 acres.
• Assuming 200 × 200 ft or 400 × 400 ft is an acre: 200 × 200 ft is 40,000 ft², or 0.9183 acres, and 400 × 400 ft is 160,000 ft², or 3.6731 acres. Multiply the two sides first, then divide by 43,560.
• Mixing up feet and square feet: 43,560 is a count of square feet (ft²). If you know the sides in feet, use "Length × width"; typing a length into the square-feet field gives a very different answer.
• Swapping acres and hectares: 1 hectare is about 2.47 acres, so "50 ha" is more than twice the land of "50 acres". Check the unit symbol before copying a figure from one source to another.
• Old survey-foot acres: until the end of 2022 the U.S. also used an acre defined with the survey foot (about 4,046.8726 m²). NIST says the international foot has been the standard since January 1, 2023, and that the survey foot should be avoided except for historic and legacy uses. The two acres differ by about 0.016 m² per acre (about 4 parts per million), roughly 162 m² over 10,000 acres. It matters only when you recompute figures from old survey records.

Limits

• Only the international-foot acre (4,046.8564224 m²) is calculated. The older U.S. survey-foot acre and regional land units whose size varies by country or area are not covered.
• The plan is a drawing for comparing sizes. In area mode it draws your land as a square, and it does not reflect the real shape, slope or survey error of a plot.
• Fields are rounded to the decimals you choose, and values with a long whole part show at most 10 significant digits. For the full value, read the result sentence and the formula.
• Areas from 0 up to 1 billion (in the entered unit) are accepted, and each side in length × width can be up to 1,000,000.
• Calculation happens in your browser and nothing is sent anywhere. "Copy link" puts the entered values into the address.

Basis: the acre, foot and hectare conversions are definitions and do not change from year to year. The NIST tables, the UK Weights and Measures Act, the BLM survey terms, the USDA figures, the field dimensions and the Tokyo Dome area were checked against the original sources on October 21, 2026.

Sources

• 01NIST Handbook 44 (2026) Appendix C — General Tables of Units of Measurement1 acre = 43 560 square feet = 160 square rods = 10 square chains; 1 square mile = 640 acres; 0.404 685 642 24 hectare (exact)
• 02NIST Handbook 44 (2024) Appendix CInternational-foot acre 4,046.856 422 4 m²; survey-foot acre 4,046.872 609 874 m²
• 03NIST — U.S. Survey FootInternational foot (1 ft = 0.3048 m) in force from January 1, 2023; survey foot to be avoided except for historic and legacy uses
• 04Weights and Measures Act 1985, Schedule 1Part VI: Acre = 4840 square yards, Square mile = 640 acres (supplementary indication only in trade); Part II: Hectare = 100 ares
• 05BLM — Glossary of Cadastral Surveying TermsAn acre equals 10 square chains or 43,560 square feet; section 640 acres; quarter section 160 acres; quarter-quarter section about 40 acres
• 06BLM — Specifications for Descriptions of LandEach township is subdivided into 36 sections, each nominally 1 mile square, 640 acres
• 07USDA NASS — 2022 Census of Agriculture release (2024-02-13)1.9 million farms and ranches, average size 463 acres
• 08FIFA — Pitch dimensions and surrounding areasRecommended field of play 105 m × 68 m
• 09NFL Rulebook, Rule 1 The Field360 feet in length and 160 feet in width, end zones included
• 10Tokyo Dome — About Tokyo DomeBuilding area 46,755 m²

Frequently asked questions

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