Convert between ten different area units in one tool, using factors derived from the 1959 international yard-and-pound agreement. Pick source and target units from the dropdowns, type a value, and the result appears instantly. Bidirectional: edit either field and the other updates. Quick-pick buttons jump to the most common pairs.
The formula
Every conversion routes through square metres as a canonical base:
This keeps the math simple and makes every unit pair share the same exact factors. Adding a new unit means adding one more entry to the base table — no per-pair work needed.
Supported units
Small scale (from smallest):
- Square millimetres (mm²) = 0.000001 m²
- Square centimetres (cm²) = 0.0001 m²
- Square inches (in²) = 0.00064516 m² (= 0.0254²)
- Square feet (ft²) = 0.09290304 m² (= 0.3048²)
- Square yards (yd²) = 0.83612736 m² (= 0.9144²)
- Square metres (m²) = 1 m² (base unit)
Large scale (land and regional):
- Acres = 4046.8564224 m² (4840 sq yd, exactly)
- Hectares = 10,000 m² (100 × 100 m square)
- Square kilometres (km²) = 1,000,000 m²
- Square miles (mi²) = 2,589,988.110336 m² (1609.344²)
Every factor is exact. The smallest unit (mm²) is 15 orders of magnitude smaller than the largest (mi²), which is why ordinary floating-point math can start losing precision at the extremes — this tool still works but expect rounding in the last few decimal places for mm² ↔ mi² conversions.
Example: a residential floor plan
A typical US house is quoted as 2,000 ft². Using the converter:
- 2,000 ft² = 185.81 m² = 0.01858 hectares = 0.00018581 km²
- Or in the other direction: 0.0459 acres (tiny — residential lots are much bigger than the house itself)
Example: a small plot of land
A quarter-acre lot (common US suburban size) is:
- 0.25 acres = 1,011.71 m² = 0.1012 hectares = 10,889 ft² = 1,210 yd²
Notice how the same physical plot reads very differently depending on which unit you use. “1,012 square metres” sounds large to a European; “quarter acre” is a modest starter home lot to an American.
Example: a geographic region
The Netherlands is about 41,865 km². Converting:
- 41,865 km² = 4,186,500 hectares = 10,345,370 acres = 16,164 sq mi
For comparison, New Jersey is 22,608 km² — about half the size of the Netherlands. The Great Barrier Reef marine park covers roughly 344,400 km², or about 8 times the Netherlands.
Quick picks
The buttons at the top of the tool set the source/target units in one click:
- m² ↔ ft² — home and room area (the most common residential pair)
- ft² ↔ m² — the reverse, for European readers of US listings
- acre ↔ ha — land area (the most common rural/agricultural pair)
- ha ↔ acre — the reverse
- km² ↔ mi² — regional and national geography
These are the pairs that come up most often in real searches; the other 95 possible pair combinations are still available through the dropdowns.
What this tool does not do
It doesn’t convert between area and volume — those are different physical quantities and the conversion would require an extra piece of information (depth) that the tool doesn’t collect. The volume converter handles volume-to-volume conversions; use it in combination with depth to get volume from area.
It doesn’t handle historical or regional units — roods (a quarter-acre), arpents (Louisiana and Quebec French colonial), or pyeong (Korean, ~3.3 m²). Each of those would need a dedicated converter.
It doesn’t compute perimeter, volume, or diagonal from an area — area alone doesn’t determine shape. To get those you’d need to know the shape (square, rectangle, circle) and at least one other dimension. For linear-only conversions, the length converter covers that axis directly.