Lawn Size Calculator UK —
Calculate Your Lawn Area in m²

The most practical method for an irregular UK lawn is the strip method. Divide your lawn into a series of parallel strips of equal width — for most lawns, a strip width of 1 metre works well. Measure the length of each strip from one curved boundary to the other. Multiply each strip length by the strip width to get the area of each strip. Add all the strip areas together to get the total lawn area. For example: if you have 10 strips each 1 metre wide with average lengths of 8, 9, 10, 11, 12, 12, 11, 10, 9, 8 metres — the total area is (8+9+10+11+12+12+11+10+9+8) × 1 = 100m². The narrower your strips, the more accurate the result. Alternatively, use the Multi-Sections tab in the calculator above to add individual rectangular sections of your lawn together — this is the fastest method for lawns that are approximately L-shaped, T-shaped or made up of connected rectangular areas.

The average UK back garden is approximately 90–100m² of lawn area, based on analysis of typical UK residential property plot sizes. However, this varies significantly by property type and region. London terraced house gardens average 40–60m². 1960s–1980s UK semi-detached properties typically have 60–120m² of lawn. Detached properties from the same era often have 120–250m². New-build properties built after 2000 frequently have smaller gardens — 30–60m² is common for new-build estate properties. Rural and pre-war properties can have lawns of 300m²–1,000m² or more. As a rough rule: one full roll of turf (1m × 10m = 10m²) is approximately one-tenth of an average UK back garden lawn. So for a 100m² average lawn, you would need approximately 10 rolls of turf to cover the entire area.

100 square metres is equal to 1,076.39 square feet. The conversion factor is: 1 m² = 10.7639 sq ft. So to convert any m² to square feet, multiply by 10.7639. Other useful conversions for 100m²: 100m² = 119.60 square yards · 100m² = 0.02471 acres · 100m² = 0.01 hectares. Going the other way: 1 square foot = 0.0929 m² · 1 square yard = 0.8361 m² · 1 acre = 4,046.86 m² · 1 hectare = 10,000 m². These conversions are all available instantly in the calculator above — enter your lawn dimensions and all unit conversions are shown simultaneously in the results panel.

For most UK lawn treatments, a measurement accuracy of ±5–10% is sufficient. This is because: (1) product application rates have a natural tolerance of ±10–15% in practice due to uneven spreading; (2) all lawn product packaging recommends buying slightly more than your calculated requirement to allow for this; and (3) treatments like fertiliser and weedkiller are applied at rates where modest over- or under-application is not damaging. The situations where greater accuracy matters are: ordering turf (where a 10% error means a significant wasted cost per roll), professional treatment services (where you pay per m²), and seeding a new lawn (where seed is expensive at £8–£15 per kg). For turf orders, always measure twice and add 10% for wastage. For quick reference: stepping out your lawn in paces (1 pace ≈ 0.75m for most adults) gives a rough estimate accurate to within 15–20% — sufficient for a first estimate of product needs before buying.

For treatment and product purposes, always calculate the horizontal (plan) area of your lawn — not the slope surface area. This is because lawn products (seed, fertiliser, weedkiller, moss killer) are applied based on the plan area, and a sloped lawn of 100m² plan area will need the same amount of fertiliser as a flat 100m² lawn regardless of the slope gradient. To measure a sloped lawn accurately: hold the tape measure level (horizontal) rather than following the contour of the slope. For steep slopes, an assistant holding one end at the lower point while you hold the other end level at the upper point will give an accurate horizontal measurement. If you use Google Maps or satellite measurement tools to estimate area, the measurement is automatically the plan (horizontal) area, which is what you need. Only if you are ordering materials for hard landscaping or drainage purposes would you need the true slope surface area — for all lawn care products, use the horizontal plan area.