How to Convert Acres to Hectares

To convert acres to hectares, multiply the number of acres by 0.404686, so 10 acres equals 4.04686 hectares. One hectare is 10,000 square meters, while one acre is 4,046.86 square meters, which is why the factor is just under one half. Convert any land area instantly with our free unit converter.

The Formula: Multiply Acres by 0.404686

The entire conversion is one multiplication: hectares = acres × 0.404686. The factor comes from the exact definitions of the two units. An acre is defined as 4,046.8564224 square meters, and a hectare is defined as exactly 10,000 square meters, so one acre divided by one hectare gives 4,046.8564224 / 10,000 = 0.40468564224, rounded to 0.404686 for everyday use. That is the whole method, and it never changes: the units are fixed by definition, so the factor is exact rather than approximate. For quick mental math you can round further to 0.4, which understates the answer by about 1.2 percent — fine for a rough sense of a property listing, but not for a purchase, a survey, or a legal document, where the full 0.404686 matters. The same multiply-by-a-fixed-factor logic powers every conversion on this site, from the square feet to square meters converter for room sizes to the length converters for fencing and boundaries, so learning the pattern once pays off across every land measurement you will ever make.

Worked Examples: 1, 5, 10, 50, and 100 Acres

Start with the anchor: 1 acre = 0.404686 hectares. From there, every example is the same multiplication. Five acres is 5 × 0.404686 = 2.02343 hectares, about two hectares, which is a typical smallholding or a large suburban lot with outbuildings. Ten acres is 10 × 0.404686 = 4.04686 hectares, a common size for a hobby farm or a rural homesite. Fifty acres is 50 × 0.404686 = 20.2343 hectares, and 100 acres is 100 × 0.404686 = 40.4686 hectares, a size most people meet in farm sales and conservation land. Notice the pattern: the answer is always a little over 40 percent of the acre figure, so a quick sanity check is to halve the acres and then add back a small amount — half of 100 is 50, and the true answer, 40.47, is well below that, because 0.404686 is closer to two-fifths than to one-half. For a real-world anchor, our football field in acres guide shows that an American football field including end zones covers about 1.32 acres, or roughly 0.53 hectares, which helps you picture any of these numbers on the ground.

The Reverse Direction: Hectares to Acres

Going the other way divides instead of multiplying, or equivalently multiplies by the reciprocal: acres = hectares × 2.47105. One hectare is 2.47105 acres, so 10 hectares is 24.7105 acres and 100 hectares is 247.105 acres. The common mistake is to multiply in both directions, which produces nonsense: multiplying 10 acres by 2.47105 gives 24.7, which is the answer to the reverse question, not the one asked. A sanity check catches the error instantly: hectares must always be the smaller number, because a hectare is bigger than an acre, so converting acres to hectares must shrink the figure and converting hectares to acres must grow it. If your conversion makes the number bigger when it should shrink, you have used the reciprocal. The same direction discipline applies to every metric-imperial pair, from land area to the centimeters to inches converter, where dividing by 2.54 rather than multiplying is the reverse trip. For a single value, the free unit converter runs both directions without the arithmetic.

Acres to Hectares Conversion Table

A short table covers the values land listings use most often. One acre is 0.4047 hectares; 2 acres is 0.8094; 5 acres is 2.0234; 10 acres is 4.0469; 20 acres is 8.0937; 25 acres is 10.1171; 50 acres is 20.2343; 100 acres is 40.4686; 500 acres is 202.343; and 1,000 acres is 404.686 hectares. Two landmarks are worth memorizing: 2.471 acres is almost exactly 1 hectare, so a 2.5-acre lot is just over a hectare, and 247 acres is about 100 hectares, a round figure that appears in farm and forestry reporting. Note the rounding rule used here: four decimal places for values under 100 acres, two for larger ones, because nobody prices farmland to the ten-thousandth of a hectare. If your listing, deed, or grant application needs more precision, keep the full 0.40468564224 factor through the calculation and round only the final answer. Our square feet to square meters formula guide uses the same keep-precision-until-the-end habit for the smaller land units that feed into acreage figures.

When to Use Acres and When to Use Hectares

The choice is mostly about audience, not accuracy. Acres dominate in the United States, where deeds, farm sales, and zoning documents are written in acres, and in the United Kingdom, where land is still commonly marketed in acres alongside hectares. Hectares dominate everywhere else: the European Union, Australia, Canada, and international forestry, agriculture, and conservation reporting all use hectares, and scientific papers report field sizes in hectares or square meters. A listing aimed at US buyers should lead with acres; a grant application, an environmental report, or an international sale should lead with hectares, with acres in parentheses if the buyer pool is mixed. The same audience logic applies to smaller units: a house plot is usually square feet or square meters, a farm is acres or hectares, and a county or a forest is square miles or square kilometers, as our quarter acre in square feet guide shows for the smallest end of the scale. Converting cleanly between the systems is a courtesy to the reader and a signal of professionalism in any land document.

Mistakes to Avoid With Acre-Hectare Conversions

Four errors account for nearly every wrong acre-to-hectare conversion. First, using 0.4 as the factor for a legal or financial figure, which understates 100 acres by more than 1.1 hectares — enough to matter in a price-per-hectare calculation. Second, swapping the direction and multiplying acres by 2.47105, which inflates the answer by a factor of six. Third, confusing acres with square feet: an acre is 43,560 square feet, and a hectare is 107,639 square feet, so a lot described as 43,560 square feet is exactly one acre but only 0.4047 hectares. Fourth, mixing US survey feet with international feet in older deeds, a rare but real source of tiny discrepancies in historic boundaries. The fix for all four is the same habit: write the formula down, check the direction with the smaller-number rule, and verify the final figure with our free unit converter before it goes into a document anyone will rely on.

Acres, Hectares, and Square Meters: The Full Ladder

Land units form a ladder, and acres and hectares sit in the middle of it. At the bottom are square feet and square meters, the units of rooms and house plots: one acre is 43,560 square feet and one hectare is 107,639 square feet, while in metric terms an acre is 4,046.86 square meters and a hectare is exactly 10,000. Above acres and hectares sit square miles and square kilometers: one square mile is 640 acres, and one square kilometer is 100 hectares, so a 640-acre section of farmland is exactly one square mile, and a 100-hectare forest block is exactly one square kilometer. That neatness is no accident: the metric ladder is decimal all the way up (100 ares make a hectare, 100 hectares make a square kilometer), while the imperial ladder mixes factors (43,560 square feet per acre, 640 acres per square mile) inherited from medieval field measurements. For practical work, convert at the rung you are given and only step up or down the ladder once: a lot given in square feet becomes acres by dividing by 43,560, then hectares by multiplying by 0.404686, and each extra conversion is a chance to round early and drift. Our square feet to square meters converter handles the bottom rung, and the free unit converter handles the whole ladder in one place, so a single source value can be expressed at every rung without retyping.