Land areas appear in a confusing mixture of units depending on context: UK property listings use acres or hectares, agricultural land uses both, urban planning uses hectares, and garden measurements use square metres. When comparing plots or making sense of a land purchase, these conversions matter.
The Core Units
- Square metre (m²): metric base unit, most familiar from property floor areas
- Hectare (ha): 10,000 m² — the standard for agricultural land in Europe
- Acre: traditional English unit, still widely used in UK property. 1 acre = 4,047 m² = 0.4047 ha
- Square kilometre: 1,000,000 m² = 100 hectares
Our unit converter handles related conversions; our area calculator converts between m² and ft² and other area units.
Key Conversions
- 1 acre = 4,047 m² = 0.4047 ha
- 1 hectare = 10,000 m² = 2.471 acres
- 1 square mile = 640 acres = 259 hectares
- 1 football pitch ≈ 0.7-0.8 hectares (useful mental benchmark)
How Big Is an Acre?
Precisely 4,047 m² — roughly 70m × 58m, or about 0.6 of a typical football pitch. An acre is substantial for a garden, modest for a smallholding, and tiny for a farm. UK small farms: 10-50 hectares. Large arable farms in East Anglia: 500+ hectares.
Measuring Irregular Plot Boundaries
For irregular plots: break the boundary into triangles or rectangles and calculate each area. For properties with surveyed coordinate boundaries, GIS software (or the Surveyor's Shoelace Formula) calculates exact polygon areas from boundary coordinate pairs.
Land Registry and Legal Measurement
HM Land Registry records use metric measurements. Title plans show areas in m² or hectares. For any legal property transaction, use the officially registered area rather than listing descriptions — these can differ, particularly for older properties.
Why Unit Consistency Matters
Agricultural land is priced per acre in the UK; planning documents reference m² or hectares. An estate agent listing "1.5-acre plot" and a planning document referencing "0.6 hectares" may describe the same land. Always convert to one consistent unit before comparing or negotiating on price.
Further reading: HM Land Registry provides guidance on understanding property title plans and registered areas. Read the Land Registry guide to title plans.