Grass seed calculator
Grass seed calculator:
pounds and bags by grass type
Every grass has its own seeding rate, and overseeding takes a half to a third of it. Enter the lawn, pick the grass, and get the pounds and the bags — with the days until it comes up.
Enter your lawnOptional
What will it cost?
Every material the calculator worked out gets its own price. Each field starts at a typical US figure so you have something to work from — change any of them to what your own supplier charges.
These prices are approximate. They are national US retail figures, and what you actually pay varies with your region, your supplier, the season and how much you buy at once. Treat them as a starting point, not a quote — always price the job from your own supplier's current figures before you order.
Your prices
More in this series
The rest of the yard
A yard is rarely one material: stone under the path, soil to fill, sod or seed on top, fertilizer after. Each has its own calculator, built for how that material is sold.
- Gravel Calculator Gravel, crushed stone, sand and road base by volume, tons and bags
- Mulch Calculator Cubic yards, bags or bales of mulch for every bed, topped up over the old layer
- Topsoil Calculator Cubic yards, tons and bags of topsoil, fill dirt or compost, with settling
- Sod Calculator Rolls or slabs of sod, pallets, pallet weight and what a trailer carries, with waste for cuts
- Fertilizer Calculator Pounds and bags of lawn fertilizer from the nitrogen rate or the bag label, with the N, P and K actually applied
- Crushed Stone Sizes and Coverage What each stone grade is for, and what a ton and a yard cover
- Topsoil Weight and Coverage What a yard of soil weighs dry, moist and wet, and how far it spreads
- Mulch Coverage, Bags and Weight How far a yard and a bag of mulch spread, and what they weigh
- Gravel and Sand Weight per Yard What a cubic yard and a ton of gravel, sand and crushed stone weigh, how far a ton goes, and what a truck carries
- Grass Seed Germination and Planting Times How many days each grass takes to come up, when to plant it, how deep, and how to water a new seeding
- Sod Pallet Sizes and Weights Square feet and pieces on a pallet of sod, what a pallet, roll and slab weigh, what a truck can carry, and how long sod keeps
- Lawn Seed and Fertilizer Rates How often to fertilize, pounds of seed per 1,000 sq ft and per acre, fertilizer by NPK, how much lime, and when to overseed
- New Sod Watering and Rooting A week-by-week watering schedule for new sod, how long it takes to root, and when you can walk on, mow and feed it
Tools for the job
What makes this job easier
Tools and materials that suit this kind of job. These are affiliate links: if you buy through one, Renovimo may earn a commission at no extra cost to you. It never changes the figures on this page.
Garvee
Broadcast spreader, 70 lb
Spreads seed, fertilizer and lime evenly over new topsoil.
Check price
Garvee
Steel garden rake, 14 tines
Loosens the surface and rakes seed lightly in — a quarter inch, no deeper.
Check price
Garvee
Lawn roller and aerator
Firms new topsoil and seed so the surface does not sink unevenly.
Check price
Garvee
Electric dethatcher and scarifier
Clears the thatch from a tired lawn so overseed lands on soil, not on dead grass.
Check price
Garvee
Rolling spike aerator, 18 in
Opens the soil before overseeding or feeding, so seed and fertilizer reach the roots.
Check price
Garvee
Stainless steel garden hose, 100 ft
Reaches the far corner of the lawn for the twice-a-day watering new sod and seed need.
Check price
Not the tool you were after? Browse the whole range at Garvee — the store these picks come from.
Based on your result
What you'll need
Loosen and rake the soil first — seed that lands on a hard crust washes off or dries out before it roots.
- Grass seed
- Bags of the grass you picked, at its rate
- Calculate above
- Starter fertilizer
- Spread the same day you seed; one bag covers about 5,000 sq ft
- —
- Straw
- A light cover that holds moisture; one 50 lb bale covers about 1,000 sq ft
- —
- Broadcast spreader
- Spreads seed evenly — go over the lawn twice at half the rate, crosswise
- 1
Seeding rates
Grass seed per 1000 square feet and per acre by grass type
The new-lawn rate is for bare soil. Overseeding a lawn that is already there takes a half to a third of it.
| Grass | New lawn, per 1,000 sq ft | Overseed, per 1,000 sq ft | New lawn, per acre | Comes up in |
|---|---|---|---|---|
| Kentucky bluegrass | 2 lb | 1 lb | 87 lb | 14–21 days |
| Tall fescue | 8 lb | 4 lb | 348 lb | 6–12 days |
| Perennial ryegrass | 6 lb | 3 lb | 261 lb | 3–7 days |
| Fine fescue (creeping red, chewings) | 5 lb | 2.5 lb | 218 lb | 6–14 days |
| Sun and shade mix | 6.7 lb | 2 lb | 292 lb | 3–21 days |
| Bermuda (hulled) | 1 lb | 0.5 lb | 44 lb | 10–20 days |
| Zoysia | 2 lb | 1 lb | 87 lb | 10–14 days |
| Centipede | 0.5 lb | 0.25 lb | 22 lb | 10–20 days |
When to sow each grass and how to water it is on the germination and planting times guide; the fertilizer that goes down with it is on lawn seed and fertilizer rates.
The maths
How much grass seed do I need?
The lawn the calculator opens with is 40 by 25 feet, 1,000 square feet. New tall fescue goes down at 8 lb per 1,000 sq ft, so it takes 8 lb — one 20 lb bag with seed to spare for thin spots.
bags = ⌈ pounds ÷ bag size ⌉
per acre = rate × 43.56
- 01
Measure the lawn
Length and width for a rectangle, diameter for a round lawn, base and height for a corner — or type the square feet or acres.
- 02
Pick the grass
The rate is the whole answer: a pound of Kentucky bluegrass covers 500 sq ft, a pound of tall fescue only 125, because fescue seed is so much bigger.
- 03
New lawn or overseeding
Seeding bare soil takes the full rate; thickening a lawn that is already there takes a half to a third of it.
- 04
Round up to bags
Seed is sold by the bag. Keep what is left for the bare patches that always show up in spring.
Good to know
How this grass seed calculator works, and other questions
8 lb of tall fescue, 6 lb of perennial ryegrass or 2 lb of Kentucky bluegrass for a new lawn; about half that to overseed.
348 lb of tall fescue for a new lawn — an acre is 43,560 sq ft, 43.56 times the per-1,000 rate. Kentucky bluegrass takes 87 lb.
Yes. Seedlings packed too tight compete for water and light, stay weak and catch disease; the lawn ends up thinner, not thicker. Stay at the rate.
Late summer to early fall for cool-season grasses, late spring to early summer for warm-season ones. The planting guide has the windows and soil temperatures. Planting times →
3–7 days for perennial ryegrass, 6–12 days for tall fescue, 14–21 days for Kentucky bluegrass, in soil that is warm enough and kept damp.
A light straw cover helps on slopes and in hot weather: it holds moisture and stops the seed washing away. One 50 lb bale covers about 1,000 sq ft — thin enough that half the soil still shows.