Lawn Seed Calculator

Pick a lawn mix and tell us the area. We work out how much seed to buy for a new lawn or to thicken an old one.

H

Creator

Haali

Updated October 2026

Calculate your lawn seed

Results update as you type

Units
Job
Area
Total area
Length
Width
Lawn mix
Sowing rate
Bag size
Bag size
Price per bag (optional)
per bag

Lawn area
Sowing rate
Estimated cost

Enter your measurements above to see how much lawn seed to buy.

How do I choose a lawn mix?

Most lawns are sown with a blend rather than a single grass. The mix decides how the lawn looks, how much wear it takes and how it copes with shade or drought.

Sunny lawn mix

Bluegrass, ryegrass and fescue together.

Best for open, everyday lawns

Shade mix

Mostly fine fescues that cope with less light.

Best under trees and by walls

Hard wearing play mix

Heavy on perennial ryegrass. Recovers fast.

Best for kids, dogs and sport

Fine ornamental lawn

Fine fescues and bents for a dense, low sward.

Best for show lawns

Drought tolerant mix

Deep rooted tall fescue types.

Best for dry, sunny sites

Planning the rest of the job? Use the Grass seed calculator and the Sod calculator too.

Sowing rates

Sunny lawn mix 5 lb new, 2.5 lb overseed per 1,000 ft²
Shade mix 4.5 lb new, 2.5 lb overseed
Hard wearing play mix 7 lb new, 4 lb overseed
Fine ornamental lawn 7 lb new, 3.5 lb overseed
Drought tolerant mix 7 lb new, 4 lb overseed

In metric, multiply by 4.9 to get grams per m². A rate of 7 lb per 1,000 ft² is about 34 g/m². The rate on your seed bag always wins.

How does the calculation work?

Seed = area ÷ 1,000 × rate

A new play lawn of 2,000 ft²: 2 × 7 = 14 lb, so one 20 lb bag. Overseeding the same lawn needs about 8 lb.

For a good result

Rake the soil to a fine, firm, level surface before sowing.
Sow half the seed one way and half at right angles for even cover.
Rake lightly so the seed is just covered, then water with a fine spray.
Keep the surface damp until the grass is about 2 in (5 cm) tall.
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