# How much grass seed do I need?

Computes the pounds of grass seed for a new lawn from the area and the grass, using extension seeding rates per 1,000 sq ft, or a rate you type, with the bags to buy.

- Page: https://www.acalculator.org/construction/grass-seed-calculator
- JSON spec: https://www.acalculator.org/construction/grass-seed-calculator.json
- Version: d86075e0d063

## Default answer

Example with the default inputs (Lawn area 5,000 ft², Grass Tall fescue, Rate unit lb per 1,000 sq ft): Seeding 5,000 ft² needs about 30 lb of grass seed.

## Inputs

| Key | Label | Description |
| --- | --- | --- |
| area | Lawn area | The area to seed. |
| grass | Grass | The grass or mix you will sow, which sets the seeding rate. |
| rate | My seeding rate | A seeding rate from the seed label, in the unit below. Leave empty to use the rate for the grass. |
| ru | Rate unit | Whether your seeding rate is in pounds per 1,000 sq ft or grams per square metre. |
| bag | Bag weight | The weight of one bag of seed. Leave empty to skip the bag count. |

## Outputs

| Key | Label | Description |
| --- | --- | --- |
| seed | Seed to buy | The seeding rate × the area: your rate, or the high end of the rate for the grass. |
| low | At the low rate | The low end of the grass’s seeding rate × the area. |
| high | At the high rate | The high end of the grass’s seeding rate × the area. |
| rateUsed | Seeding rate used | The rate behind the seed to buy, in pounds per 1,000 sq ft. |
| bags | Bags | The seed to buy ÷ the bag weight, rounded up. |

## Method

Seed = seeding rate (lb per 1,000 sq ft) × area ÷ 1,000 sq ft; with no rate typed, the high end of the grass’s rate; bags = seed ÷ bag weight, rounded up.

## Assumptions

- Rates are NC State Extension’s for a new lawn (Table 9-4); mixes add the rate of each grass. The rate on your seed label comes first.
- For overseeding, type the rate from the seed label.
- 1 lb per 1,000 sq ft is about 4.88 g per m².

## Worked examples

1. area = 464.5152, grass = kentucky-bluegrass, ru = lb1000 gives seed = 4.535924, low = 3.401943, high = 4.535924, rateUsed = 2. Source: NC State Extension, Extension Gardener Handbook, chapter 9 Lawns, Table 9-4 Planting dates and rates for cool- and warm-season grasses (pounds of seed per 1,000 sq ft: Kentucky bluegrass 1.5–2; tall fescue 6; Kentucky bluegrass + fine fescue 1.5 + 1.5; Kentucky bluegrass + tall fescue 1 + 5; with fine fescue 1 + 5 + 1; Kentucky bluegrass + perennial ryegrass 1.5 + 1; bermudagrass 1–2; bahiagrass 5; centipedegrass 0.25–0.5; zoysiagrass 1–2), https://content.ces.ncsu.edu/extension-gardener-handbook/9-lawns (retrieved 2026-10-03).
2. area = 232.2576, grass = tall-fescue, ru = lb1000, bag = 2.267962 gives seed = 6.803886, bags = 3. Source: NC State Extension, Extension Gardener Handbook, chapter 9 Lawns, Table 9-4 Planting dates and rates for cool- and warm-season grasses (pounds of seed per 1,000 sq ft: Kentucky bluegrass 1.5–2; tall fescue 6; Kentucky bluegrass + fine fescue 1.5 + 1.5; Kentucky bluegrass + tall fescue 1 + 5; with fine fescue 1 + 5 + 1; Kentucky bluegrass + perennial ryegrass 1.5 + 1; bermudagrass 1–2; bahiagrass 5; centipedegrass 0.25–0.5; zoysiagrass 1–2), https://content.ces.ncsu.edu/extension-gardener-handbook/9-lawns (retrieved 2026-10-03).
3. area = 200, grass = tall-fescue, rate = 30, ru = gm2 gives seed = 6, rateUsed = 6.144484. Source: NC State Extension, Extension Gardener Handbook, chapter 9 Lawns, Table 9-4 Planting dates and rates for cool- and warm-season grasses (pounds of seed per 1,000 sq ft: Kentucky bluegrass 1.5–2; tall fescue 6; Kentucky bluegrass + fine fescue 1.5 + 1.5; Kentucky bluegrass + tall fescue 1 + 5; with fine fescue 1 + 5 + 1; Kentucky bluegrass + perennial ryegrass 1.5 + 1; bermudagrass 1–2; bahiagrass 5; centipedegrass 0.25–0.5; zoysiagrass 1–2), https://content.ces.ncsu.edu/extension-gardener-handbook/9-lawns (retrieved 2026-10-03).
4. area = 278.70912, grass = centipedegrass, ru = lb1000 gives low = 0.340194, high = 0.680389. Source: NC State Extension, Extension Gardener Handbook, chapter 9 Lawns, Table 9-4 Planting dates and rates for cool- and warm-season grasses (pounds of seed per 1,000 sq ft: Kentucky bluegrass 1.5–2; tall fescue 6; Kentucky bluegrass + fine fescue 1.5 + 1.5; Kentucky bluegrass + tall fescue 1 + 5; with fine fescue 1 + 5 + 1; Kentucky bluegrass + perennial ryegrass 1.5 + 1; bermudagrass 1–2; bahiagrass 5; centipedegrass 0.25–0.5; zoysiagrass 1–2), https://content.ces.ncsu.edu/extension-gardener-handbook/9-lawns (retrieved 2026-10-03).

## FAQ

### How much grass seed do I need per 1,000 sq ft?

It depends on the grass. NC State Extension gives 6 lb per 1,000 sq ft for tall fescue, 1.5 to 2 lb for Kentucky bluegrass, 1 to 2 lb for bermudagrass and zoysiagrass, 5 lb for bahiagrass and 0.25 to 0.5 lb for centipedegrass.

### What if my grass is not in the list?

Pick any grass and type the rate from your seed label in “My seeding rate”. The calculator then uses your rate for the seed to buy and the bags.

### How does the calculator handle a range such as 1.5 to 2 lb?

It shows the seed at both ends, and uses the high end as the seed to buy so you do not run short. Type your own rate to use that instead.

### How do I seed a mix?

Pick the mix. NC State adds the rate of each grass: Kentucky bluegrass with tall fescue is 1 + 5 = 6 lb per 1,000 sq ft, and with fine fescue too, 1 + 5 + 1 = 7 lb.

### Should I follow the bag label or the calculator?

The label. Seed blends differ in seed size and purity, and the maker’s rate allows for that. Type the label rate in “My seeding rate”; grams per square metre work too.

### How much seed for overseeding?

Overseeding a thin lawn needs its own rate, which the seed label gives. Type it in “My seeding rate” for the pounds to buy.

## Sources

- NC State Extension, Extension Gardener Handbook, chapter 9 Lawns, Table 9-4 Planting dates and rates for cool- and warm-season grasses in North Carolina (pounds of seed per 1,000 sq ft), retrieved 2026-10-03. https://content.ces.ncsu.edu/extension-gardener-handbook/9-lawns