Free calculator
Grass seed calculator: lb or kg by grass type
With the US starting values (1,000 sq ft of tall fescue (turf-type), new lawn at 7 lb per 1,000 sq ft, Penn State Extension, Lawn Establishment, Table 1; 10 lb bags), you need 7 lb of seed, so 1 bag of 10 lb ($53.00 at $53.00 a bag). Pick your grass type and whether it is a new lawn or overseeding; the rate changes with both.
The area is shared: change it here and the other two calculators and the Pro plan use the same lawn.
Result
- Lawn area
- 1,000 sq ft
- Seed rate
- 7 lb per 1,000 sq ft
- Seed to buy
- 7 lb
- Bags of 10 lb
- 0.7 (buy 1 bag)
- Cost of the bags
- $53.00
Seed = area × rate; bags = seed ÷ bag weight, rounded up; cost = bags × the price you typed. Starting rate for tall fescue (turf-type), new lawn: Penn State Extension, Lawn Establishment, Table 1, read 2026-09-20. Rates from university extension guides and product labels, each with its source and date: the label on the bag wins.
Pro puts the three results on one printable plan with a 12-month calendar.
Sod, seed and fertilizer as a shopping list with the cost, plus mowing, feeding, overseeding and aeration month by month for your climate. Printed or exported to Excel.
How it works
Seed = lawn area × the seed rate for the grass type and the purpose. Bags = seed ÷ the bag weight, rounded up to what you buy. Cost = bags × the price you typed. The rate is the starting value the extension guide or the seed label gives for that grass and purpose; overseeding an existing lawn takes about half the new-lawn rate, and where a guide gives no overseeding figure the calculator says so in the source line and uses that rule of thumb.
With the US starting values, 1,000 sq ft of tall fescue (turf-type) takes 7 lb as a new lawn and 4 lb for overseeding (University of Maryland Extension, Maintaining an Established Lawn, overseeding rate). In the UK a general-purpose lawn (ryegrass and fescue) mix sown at 35 g per m² (Rolawn, Overseeding a Lawn) takes 3.5 kg for 100 m²: 3.5 (buy 4 boxs) of 1 kg.
US new-lawn rates by type: kentucky bluegrass 2.5 lb per 1,000 sq ft (Penn State Extension, Lawn Establishment, Table 1 seeding rates); tall fescue (turf-type) 7 lb per 1,000 sq ft (Penn State Extension, Lawn Establishment, Table 1); perennial ryegrass 4.5 lb per 1,000 sq ft (Penn State Extension, Lawn Establishment, Table 1); fine fescue 4.5 lb per 1,000 sq ft (Penn State Extension, Lawn Establishment, Table 1); bermudagrass 1.5 lb per 1,000 sq ft (NC State Extension Gardener Handbook, chapter 9 Lawns, seeding rate); zoysiagrass 1.5 lb per 1,000 sq ft (NC State Extension Gardener Handbook, chapter 9 Lawns, seeding rate); sun and shade mix (bluegrass, fine fescue, ryegrass) 3.5 lb per 1,000 sq ft (Penn State Extension, Lawn Establishment, Table 1 mixtures). UK rates: general-purpose lawn (ryegrass and fescue) 35 g per m² (Rolawn, Overseeding a Lawn); shade lawn 35 g per m² (Johnsons Shady Lawn Seed label); hard-wearing lawn (ryegrass) 50 g per m² (Boston Seeds Quality Hard Wearing Lawn Seed, Landscape Centre listing). The calculator starts from the published figure; change it to the rate on your own bag.
Sources of the US starting values
- Kentucky bluegrass, new lawn: Penn State Extension, Lawn Establishment (updated 2025-09-19), Table 1 seeding rates (lb/1,000 sq ft): "Kentucky bluegrass: 2-3"; midpoint 2.5 used — https://extension.psu.edu/lawn-establishment, read on 2026-09-20
- Tall fescue (turf-type), new lawn: Penn State Extension, Lawn Establishment (updated 2025-09-19), Table 1: "Turf-type tall fescue: 6-8" lb/1,000 sq ft; midpoint 7 used — https://extension.psu.edu/lawn-establishment, read on 2026-09-20
- Perennial ryegrass, new lawn: Penn State Extension, Lawn Establishment (updated 2025-09-19), Table 1: "Perennial ryegrass: 4-5" lb/1,000 sq ft; midpoint 4.5 used — https://extension.psu.edu/lawn-establishment, read on 2026-09-20
- Fine fescue, new lawn: Penn State Extension, Lawn Establishment (updated 2025-09-19), Table 1: "Fine fescues: 4-5" lb/1,000 sq ft; midpoint 4.5 used — https://extension.psu.edu/lawn-establishment, read on 2026-09-20
- Bermudagrass, new lawn: NC State Extension Gardener Handbook, chapter 9 Lawns, seeding rate: bermudagrass "1–2 pounds per 1,000 sq ft"; midpoint 1.5 used — https://content.ces.ncsu.edu/extension-gardener-handbook/9-lawns, read on 2026-09-20
- Zoysiagrass, new lawn: NC State Extension Gardener Handbook, chapter 9 Lawns, seeding rate: zoysiagrass "1–2 pounds per 1,000 sq ft"; midpoint 1.5 used — https://content.ces.ncsu.edu/extension-gardener-handbook/9-lawns, read on 2026-09-20
- Sun and shade mix (bluegrass, fine fescue, ryegrass), new lawn: Penn State Extension, Lawn Establishment (updated 2025-09-19), Table 1 mixtures: "Kentucky bluegrass + fine fescues + perennial ryegrass: 3-4" lb/1,000 sq ft; midpoint 3.5 used — https://extension.psu.edu/lawn-establishment, read on 2026-09-20
- Kentucky bluegrass, overseeding: University of Maryland Extension, Maintaining an Established Lawn (updated 2026-09-14), overseeding rate: Kentucky bluegrass "1 to 1½ pounds" per 1,000 sq ft; midpoint 1.25 used — https://extension.umd.edu/resource/maintaining-established-lawn, read on 2026-09-20
- Tall fescue (turf-type), overseeding: University of Maryland Extension, Maintaining an Established Lawn (updated 2026-09-14), overseeding rate: tall fescue "4 pounds" per 1,000 sq ft — https://extension.umd.edu/resource/maintaining-established-lawn, read on 2026-09-20
- Perennial ryegrass, overseeding: Penn State Extension, Lawn Establishment (updated 2025-09-19), overseeding/renovation: "Perennial ryegrass: 4-6" lb/1,000 sq ft (a renovation seeds into competition, so the rate is not below the new-lawn rate); midpoint 5 used — https://extension.psu.edu/lawn-establishment, read on 2026-09-20
- Fine fescue, overseeding: University of Maryland Extension, Maintaining an Established Lawn (updated 2026-09-14), overseeding rate: fine fescue "2½ to 3 pounds" per 1,000 sq ft; midpoint 2.75 used — https://extension.umd.edu/resource/maintaining-established-lawn, read on 2026-09-20
- Bermudagrass, overseeding: Rule of thumb: half of the NC State new-lawn rate for bermudagrass (1-2 lb/1,000 sq ft, midpoint 1.5 → 0.75); Ohio State University Extension (Ask Extension, 2023-04-13): overseeding rates are "approximately half those used for new plantings" — https://ask.extension.org/kb/faq.php?id=824923, read on 2026-09-20
- Zoysiagrass, overseeding: Rule of thumb: half of the NC State new-lawn rate for zoysiagrass (1-2 lb/1,000 sq ft, midpoint 1.5 → 0.75); Ohio State University Extension (Ask Extension, 2023-04-13): overseeding rates are "approximately half those used for new plantings" — https://ask.extension.org/kb/faq.php?id=824923, read on 2026-09-20
- Sun and shade mix (bluegrass, fine fescue, ryegrass), overseeding: Rule of thumb: half of the Penn State new-lawn rate for the bluegrass, fine fescue and ryegrass mixture (3-4 lb/1,000 sq ft, midpoint 3.5 → 1.75); Ohio State University Extension (Ask Extension, 2023-04-13): overseeding rates are "approximately half those used for new plantings" — https://ask.extension.org/kb/faq.php?id=824923, read on 2026-09-20
- Bag size: Twin City Seed Company, Blue Resilience tall fescue and Kentucky bluegrass mixture: "10 lb Bag" — https://twincityseed.com/product/blue-resilience-tall-fescue-kentucky-bluegrass-mixture/, read on 2026-09-20
- Price per bag: Twin City Seed Company, Blue Resilience tall fescue and Kentucky bluegrass mixture: 10 lb bag $53.00 — https://twincityseed.com/product/blue-resilience-tall-fescue-kentucky-bluegrass-mixture/, read on 2026-09-20
- Starting area: Convention: 1,000 sq ft, the area US extension seed and fertilizer rates are written per (Purdue Turf, Calculating the pounds of fertilizer to apply, 2009) — https://turf.purdue.edu/calculating-the-pounds-of-fertilizer-to-apply-3/, read on 2026-09-20
UK starting values (Rolawn, Johnsons and Boston Seeds labels) show their sources under each field when you switch region.
Rates from university extension guides and product labels, each with its source and date: the label on the bag wins. Planning quantities, not agronomic advice.
Frequently asked questions
- How much grass seed per square foot?
- Extension guides write rates per 1,000 sq ft: kentucky bluegrass 2.5 lb per 1,000 sq ft (Penn State Extension, Lawn Establishment, Table 1 seeding rates); tall fescue (turf-type) 7 lb per 1,000 sq ft (Penn State Extension, Lawn Establishment, Table 1); perennial ryegrass 4.5 lb per 1,000 sq ft (Penn State Extension, Lawn Establishment, Table 1); fine fescue 4.5 lb per 1,000 sq ft (Penn State Extension, Lawn Establishment, Table 1); bermudagrass 1.5 lb per 1,000 sq ft (NC State Extension Gardener Handbook, chapter 9 Lawns, seeding rate); zoysiagrass 1.5 lb per 1,000 sq ft (NC State Extension Gardener Handbook, chapter 9 Lawns, seeding rate); sun and shade mix (bluegrass, fine fescue, ryegrass) 3.5 lb per 1,000 sq ft (Penn State Extension, Lawn Establishment, Table 1 mixtures). Per square foot that is the figure ÷ 1,000; the calculator does it for your area and grass type.
- How much grass seed for overseeding?
- About half the new-lawn rate: kentucky bluegrass 1.25 lb per 1,000 sq ft, tall fescue (turf-type) 4 lb per 1,000 sq ft, perennial ryegrass 5 lb per 1,000 sq ft, fine fescue 2.75 lb per 1,000 sq ft (University of Maryland Extension, Maintaining an Established Lawn, overseeding rate; perennial ryegrass 5 lb per 1,000 sq ft from Penn State, whose renovation rate is not below the new-lawn rate). Pick "Overseeding" in the calculator and the rate follows.
- How many bags of seed do I need?
- Seed ÷ bag weight, rounded up. With the US starting values, 1,000 sq ft of tall fescue (turf-type) is 0.7 (buy 1 bag) of 10 lb; a 5,000 sq ft lawn is 3.5 (buy 4 bags). Type the bag you actually buy; sizes differ by brand and the starting bag is only one supplier's.
- Why do the rates differ between guides?
- Seed size and climate. Kentucky bluegrass has small seed (2.5 lb per 1,000 sq ft for a new lawn), tall fescue large seed (7 lb per 1,000 sq ft), and guides written for other climates use other ranges. The calculator quotes one guide per figure with its date; if your bag says otherwise, type the bag's rate: the label wins.
- Does the calculator cover UK lawn seed in g/m²?
- Yes. Switch the region to UK / metric: general-purpose lawn (ryegrass and fescue) 35 g per m² (Rolawn, Overseeding a Lawn); shade lawn 35 g per m² (Johnsons Shady Lawn Seed label); hard-wearing lawn (ryegrass) 50 g per m² (Boston Seeds Quality Hard Wearing Lawn Seed, Landscape Centre listing); overseeding 23 g per m² to 25 g per m² on the Rolawn and Johnsons labels. The 1 kg box and its price are the starting bag.
- When should I sow?
- Cool-season lawns in the US: the Purdue calendar puts reseeding from mid-August to mid-September. Warm-season lawns: bermudagrass and zoysia are planted in late spring once the soil is warm. UK: spring or autumn (Rolawn, RHS). The Pro plan shows the window on a 12-month calendar for your climate.
Guides
- How much grass seed per square foot? (rates by grass type)
Seed rates by grass type for a new lawn and overseeding, in lb per 1,000 sq ft and kg per 100 m²; seed, sod and fertilizer by lawn size.