Sod / Grass Seed Calculator

Please fill in the required fields with values greater than 0.
–lawn area (sq ft)
–grass seed needed (lb)
–sod rolls (10 sq ft each)
–sod pallets (450 sq ft each)

Estimate only. Seeding rates vary by brand and mix, so follow the label on the bag. Sod includes 5% extra for cuts.

How to use this calculator

Enter the lawn length and width and pick the grass type and the kind of job. Press Calculate to see how many pounds of grass seed you need, or how many rolls and pallets of sod.

The formula

Area = length × width
Seed (lb) = area ÷ 1,000 × seeding rate × job factor (1 for new lawn, 0.5 for overseeding)
Sod rolls = area × 1.05 ÷ 10

Example: A 50 ft × 30 ft lawn is 1,500 sq ft. A new Kentucky bluegrass lawn needs 4.5 lb of seed. Sod needs 158 rolls, which is 4 pallets.

Getting the most from your grass seed estimate

The calculator measures your lawn area and multiplies it by the seeding rate for the grass type you choose. A new lawn uses the full rate, and overseeding uses about half. It also shows how much sod you would need instead, in 10 square foot rolls and 450 square foot pallets, so you can compare the two options.

A worked example

A 50 by 30 foot lawn is 1,500 square feet. Kentucky bluegrass is seeded at about 3 pounds per 1,000 square feet, so a new lawn needs 4.5 pounds. Tall fescue at 8 pounds per 1,000 would need 12 pounds for the same area, or 6 pounds to overseed. Sod for that lawn is 158 rolls with 5% extra, which is 4 pallets.

What changes how much seed you need

  • Grass type. Small-seeded grasses like bluegrass need fewer pounds than larger-seeded ryegrass or tall fescue.
  • Job type. Overseeding a thin lawn uses about half the new-lawn rate.
  • Seed quality. Cheaper blends may contain more filler or weed seed. Check the label for germination rate and purity.
  • Coated seed. Some seed has a coating that adds weight, so you may need more pounds for the same coverage. Follow the bag rate.

Tips and common mistakes

  • Pick a grass suited to your climate and the amount of sun the lawn gets.
  • Prepare the soil. Loosen the top inch or so, remove debris and rake it level before spreading.
  • Spread half the seed in one direction and half at a right angle for even coverage.
  • Press seed into the soil with a roller or by raking lightly. Seed sitting on top often dries out or feeds birds.
  • Keep the top layer moist with light, frequent watering until the grass is up, then water deeper and less often.
  • Do not use a weed preventer before seeding unless the label says it is safe for new grass.

Buying and cost

Seed is much cheaper than sod per square foot, but sod gives an instant lawn and controls erosion better on slopes. Buy a little extra seed to patch thin spots that show up a few weeks later. Store leftover seed in a cool, dry place. Schedule sod delivery for the day you plan to lay it, since stacked rolls can heat up and turn yellow.

Frequently asked questions

How much grass seed do I need?
Divide the lawn area by 1,000 and multiply by the seeding rate on the bag, usually 3 to 10 pounds per 1,000 square feet.
How much grass seed do I need for overseeding?
Use about half the new-lawn rate, since existing grass will help fill in the lawn.
How big is a roll of sod?
Many rolls cover about 10 square feet, and a pallet covers about 450 to 500 square feet.
When should I plant grass seed?
Cool-season grasses grow best when planted in early fall or spring. Warm-season grasses are planted in late spring and early summer.
Is sod better than seed?
Sod gives an instant lawn but costs more. Seed costs less and gives more variety but takes weeks to grow.
How long does grass seed take to grow?
Germination time depends on the grass type and soil temperature. Perennial ryegrass often sprouts in about 5 to 10 days, tall fescue in about 7 to 14 days, and Kentucky bluegrass can take 2 to 4 weeks. A new lawn usually needs 6 to 8 weeks or more before it can handle regular foot traffic.
Can I just throw grass seed on my lawn?
You can, but results are usually poor. Seed needs good contact with soil to sprout. Mow short, rake out thatch and loosen bare spots first. After spreading, rake lightly so seed settles into the soil, and keep it moist. Seed left on top of hard ground or thick thatch often fails to grow.
When should I mow new grass for the first time?
Wait until the new grass reaches about 3 to 4 inches tall. Set the mower high and remove no more than one third of the blade height. Make sure the blade is sharp so it cuts cleanly instead of pulling up young plants. Mow when the soil is dry enough not to leave footprints.