Lawn Size Calculator
Enter the length and width of your lawn and the area of any beds or paths inside it. Choose whether you are sowing a new lawn, overseeding or patching. The calculator gives the lawn area and the materials to buy.
- Area in m² and sq ft
- Seed, turf and feed
- Topsoil and water
For an odd-shaped lawn, split it into rectangles, work out each one and add them together.
Every lawn product is sold by area. Seed bags, fertiliser and weedkillers all state how many square metres they cover. Knowing your exact lawn area stops you overbuying, and stops you spreading too much, which can scorch grass.
Lawn material rates
Typical amounts per square metre. Search for a product.
| Product | Rate per m² | Per 100 m² | Per 1,000 sq ft |
|---|---|---|---|
| Grass seed, new lawn | 35 g | 3.5 kg | 7 lb |
| Grass seed, overseeding | 17 g | 1.7 kg | 3.5 lb |
| Grass seed, patching | 50 g | 5 kg | 10 lb |
| Granular fertiliser | 35 g | 3.5 kg | 7 lb |
| Lime (acid soil) | 100 g | 10 kg | 20 lb |
| Top dressing | 2 kg | 200 kg | 400 lb |
| Topsoil 5 cm | 0.05 m³ | 5 m³ | 6.5 yd³ |
| Turf | 1 roll | 105 rolls | 100 rolls (10 sq ft) |
Always check the rate on the pack. Fine ornamental seed mixes and shade mixes often have different rates.
Lawn area and materials
New lawn from seed. Slide the lawn area.
Seed is cheap compared with turf, but takes six to eight weeks to look like a lawn. Turf is usable in two to three weeks.
How to measure a lawn
Rectangles first. Step through it.
Measure length
Along the longest straight side.
A long tape and a helper make measuring easy. For curved edges, measure the widest rectangle and subtract the corners.
Seed, turf or overseed
Three ways to a green lawn. Compare them.
Cheapest per square metre. Needs time and steady watering.
Instant lawn. Must be laid within a day of delivery.
Thickens a tired lawn without starting again.
Sow seed in early autumn or spring when the soil is warm and moist. Turf can be laid almost any time the ground is not frozen.
Before sowing or turfing
Good ground makes a good lawn. Tick each item.
Tick each item as you go.
Rake the soil to a fine, level crumb and firm it by treading. Seed and turf both need close contact with the soil to root.
What you get
A shopping list for your lawn. Each tile explains one result.
In m² and sq ft.
For your type of job.
With 5% for cutting.
At a typical rate.
Per week in dry weather.
Water about 25 mm a week in dry spells. A tuna tin on the lawn fills to that depth in about the right time.
Frequently Asked Questions
No question matches that search.
How do I measure my lawn size?
Multiply length by width, then subtract any beds or paths. Split odd shapes into rectangles.
How much grass seed do I need?
About 35 g per m² for a new lawn and half that for overseeding.
How many turf rolls do I need?
One roll per square metre in the UK, plus 5% for trimming.
How much seed for 100 m²?
3.5 kg for a new lawn, 1.7 kg to overseed.
How much is a square metre in square feet?
1 m² is 10.76 sq ft.
How much topsoil for a new lawn?
A 5 cm layer is 0.05 m³ per m², so 5 m³ per 100 m².
How much water does a lawn need?
About 25 mm a week, or 25 litres per square metre.
Buy the right amount for your lawn
Measure length and width, take out the beds and you have your lawn area. Multiply by the rate on each pack and you will buy what you need, spread it evenly and get an even, green lawn.
More size calculators
Each one has its own calculator, worked examples and answers to common questions.