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Grass seed calculator

How much seed to sow: each grass type has its own recommended seeding rate per 1,000 sq ft, and overseeding an existing lawn takes about half of a new seeding. Enter the area and get the pounds needed for a new lawn and for overseeding.

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Enter Grass type, Lawn area and the Grass seed calculator works out New lawn — seed needed, Overseeding — seed needed straight away. For instance, with Grass type = Tall fescue and Lawn area = 465 m² it returns New lawn — seed needed = 13.622 kg and Overseeding — seed needed = 6.811 kg.

How to use it

  1. Enter your values: Grass type, Lawn area.
  2. Read the result instantly: New lawn — seed needed, Overseeding — seed needed.

Frequently asked questions

What does the Grass seed calculator actually compute?

It takes Grass type and Lawn area and derives New lawn — seed needed and Overseeding — seed needed from them. The calculation is live as you type, so the result updates on every change.

What information do I need to provide?

2 values: Grass type and Lawn area (m²). Nothing else is required — no account, no file upload.

Can you show a worked example?

With Grass type = Tall fescue and Lawn area = 465 m², the calculator returns New lawn — seed needed = 13.622 kg and Overseeding — seed needed = 6.811 kg. Those figures come from running this exact tool, so you can reproduce them by entering the same values.

What happens if I enter larger values?

It moves a lot. Using Grass type = Kentucky bluegrass and Lawn area = 512 m² instead, New lawn — seed needed goes from 13.622 kg to 5 kg — which is why it is worth testing a few scenarios rather than trusting a single figure.

Which “Grass type” option should I choose?

You can pick between « Tall fescue », « Kentucky bluegrass », « Perennial ryegrass », « Bermudagrass » and « Fine fescue ». Each one changes what the calculator works out, so switch and compare — the default is « Tall fescue ».

Which units should I enter the values in?

Enter Lawn area m². Metric and US units are both supported — switch system and the figures convert for you.

What does it give for smaller values?

Scaled down to Grass type = Tall fescue and Lawn area = 419 m², New lawn — seed needed comes out at 12.274 kg. The relationship is worth checking at both ends before you rely on a single result.

When would I actually use this?

Planning a bed or a lawn: how much soil to order, how much feed to spread, how far apart to plant, and when the last frost is likely.

What is the most common mistake?

Reading a frost date as a guarantee. It is the date after which frost becomes unlikely, not impossible — a late frost after planting out is exactly the risk the average conceals.

Where do the figures come from, and how current are they?

Volumes and spacings are exact geometry. Frost dates come from long-run meteorological averages for the region, and a garden's own microclimate can shift them by a week or more in either direction.

Further reading

All guides →
How-toHow Much Grass Seed Do I Need? Seed Rate by Lawn AreaWork out how much grass seed to buy from your lawn area and the seed rate — with different rates for a new lawn versus overseeding.How-toHow Much Fertilizer a Lawn Actually Needs (You Are Buying Nitrogen, Not Bags)The same 2,000 sq ft lawn at the same 1 lb of nitrogen per 1,000 sq ft takes 40 lb of a 5 percent blend or 4.3 lb of urea. Target nitrogen, not product — and read the bag count as shopping, not spreading.How-toHow Far Apart to Plant? Spacing and Plants per AreaTurn a plant-spacing figure into how many plants you need for a bed or row — including the difference between square and triangular layouts.GuideMulch Depth Is the Whole Answer — and It Is a Trade-OffTwo to four inches, and the right end of that window depends on the material: bark takes 3, screened compost takes 1 to 2, and gravel takes 1. Here is the depth trade-off, the settling nobody buys for, and the bag conversion where the count goes wrong.ExplainerThe Compost Carbon-to-Nitrogen Ratio: What 30:1 Means and Why Your Bucket Cannot Measure ItA compost heap wants 25 to 30 parts carbon to one part nitrogen by dry weight. Cardboard is 350:1, grass clippings 17:1. Here is the materials table, one mix worked through to 28:1, and why the volume rule of thumb is a different measurement entirely.ExplainerHow to Read an NPK Fertilizer Label (Two of the Three Numbers Are in Disguise)10-20-10 does not mean 10 percent phosphorus. The second and third numbers are oxides, so a 50 lb bag holds 4.4 lb of actual phosphorus, not 10. Here is what each number really measures and how to turn it into a rate.