How to measure the area to seed
- Split the lawn into simple shapes. Measure rectangles as length × width. For curved or odd-shaped areas, use the square footage calculator and enter the total here.
- Leave out beds, patios, paths and anything else that won't be seeded.
- Patch repair: measure each bare patch, roughly as a rectangle around it, and add each one with “+ Another area”. The patches are added before anything is rounded.
- Shade and slopes: estimate what share of the area is shaded for much of the day, and what share is steep or erosion-prone. Rough percentages are enough.
Seeding rates by grass type
Extension guides give a range for each grass. Small-seeded grasses such as Kentucky bluegrass and bermudagrass need far fewer pounds than large-seeded tall fescue and ryegrass (University of Tennessee Extension). We use a value inside the cited ranges, and you can always switch to “Custom rate from the seed label”.
| Grass type | New lawn range | We use | Overseeding (half) | Ranges from |
|---|---|---|---|---|
| Tall fescue | 4–9 lb | 6 lb | 3 lb | Rutgers 4–6, or 4–8 for pure tall fescue; Nebraska 6–8; UMass 7–9 |
| Kentucky bluegrass | 1–3 lb | 2 lb | 1 lb | Rutgers about 2; Nebraska 1.5–3; UMass 1–2 |
| Perennial ryegrass | 4–9 lb | 5 lb | 2.5 lb | Rutgers 4–6; UT 4–6; UMass 7–9 |
| Fine fescue | 3–6 lb | 5 lb | 2.5 lb | Rutgers 4–6; UT 3–5; UMass red fescue 4–6 |
| Bluegrass + perennial ryegrass (85/15) | 3–4 lb | 3.5 lb | 1.75 lb | Nebraska 3–4 |
| Bluegrass + fine fescue | 4–5 lb | 4.5 lb | 2.25 lb | Nebraska 4–5 |
| Tall fescue + bluegrass | 4–6 lb | 5 lb | 2.5 lb | Rutgers FS990 4–6 |
| Shade mix (fine fescue + ryegrass) | 4–6 lb | 5 lb | 2.5 lb | UMass 4–6 |
| Bermudagrass (hulled) | 0.5–4 lb | 1 lb | 0.5 lb | UT ½–1 hulled; UF 1–4 |
| Bahiagrass | 5–10 lb | 7.5 lb | 3.75 lb | UF 5–10 |
| Centipedegrass | 0.25–1 lb | 0.5 lb | 0.25 lb | UF 0.25–1 |
| Grass type | New lawn range | We use | Overseeding (half) | Ranges from |
|---|---|---|---|---|
| Tall fescue | 20–44 g | 29 g | 15 g | Rutgers, Nebraska, UMass |
| Kentucky bluegrass | 4.9–15 g | 9.8 g | 4.9 g | Rutgers, Nebraska, UMass |
| Perennial ryegrass | 20–44 g | 24 g | 12 g | Rutgers, UT, UMass |
| Fine fescue | 15–29 g | 24 g | 12 g | Rutgers, UT, UMass |
| Bluegrass + perennial ryegrass (85/15) | 15–20 g | 17 g | 8.5 g | Nebraska |
| Bluegrass + fine fescue | 20–24 g | 22 g | 11 g | Nebraska |
| Tall fescue + bluegrass | 20–29 g | 24 g | 12 g | Rutgers |
| Shade mix (fine fescue + ryegrass) | 20–29 g | 24 g | 12 g | UMass |
| Bermudagrass (hulled) | 2.4–20 g | 4.9 g | 2.4 g | UT, UF |
| Bahiagrass | 24–49 g | 37 g | 18 g | UF |
| Centipedegrass | 1.2–4.9 g | 2.4 g | 1.2 g | UF |
Rutgers notes that spring seedings need higher rates than fall seedings, and UMass recommends the high end of each range when conditions are less than ideal. Retail calculators often use higher figures (Eartheasy and InchCalculator.com list 10 lb per 1,000 ft² for tall fescue and ryegrass).
How the seed is calculated
- Rate = the grass type's new-lawn rate, halved when overseeding a thin lawn (Nebraska Extension: “when seeding into an existing lawn, the seeding rate can be cut in half”). Bare patches get the full rate.
- Seed = area ÷ 1,000 × rate. In metric, area (m²) × rate (g/m²) ÷ 1,000 gives kilograms.
- Shade: the shaded share is sown with a shade mix (80–90% fine fescue and 10–20% perennial ryegrass at 4–6 lb per 1,000 ft², from UMass) instead, and listed as a separate product.
- Slopes and poor ground: the steep share gets 50% more seed, the UMass rule of thumb for poor germination conditions. You can change the 50% under “Product sizes, prices and costs”.
- Waste is added last, then the seed is rounded up to whole bags.
With the defaults (1,000 ft²92.9 m², new tall fescue lawn, 5% waste) you need 6.3 lb2.86 kg.
New lawn, overseeding or patch repair?
- New lawn: bare, prepared soil gets the full rate. Nebraska Extension suggests overseeding instead when more than half of the lawn is still good turf.
- Overseeding: thickening a thin lawn uses about half the bare-ground rate. Mow short first and get the seed into contact with the soil, by aerating or slit-seeding, or it will sit on the thatch.
- Patch repair: bare spots have no turf to help, so they get the full new-lawn rate, but only on the patch area.
- Timing: cool-season grasses (fescues, bluegrass, ryegrass) do best seeded in late summer to early fall. In Nebraska the window is mid-August to mid-September. Warm-season grasses (bermudagrass, bahiagrass, centipedegrass) are seeded in spring and summer when the soil is warm (UF/IFAS).
Shade, slopes and mulch
More seed doesn't fix shade. Grass that can't tolerate shade will thin out whatever the rate, so the calculator switches the shaded share to a shade mix rather than adding seed. For slopes, UMass lists steep, erosion-prone grades among the conditions that justify about 50% more seed, and both UF/IFAS and UT Extension recommend a light straw mulch over new seed. One bale covers about 1,000 ft² (UF/IFAS, UT Extension), so the calculator counts bales for new lawns and patches. On steep banks, an erosion-control blanket stapled over the seed holds it better than straw.
| Situation | What the calculator does |
|---|---|
| Shaded share of the area | Sows it with a fine fescue shade mix at 5 lb per 1,000 ft², halved when overseedingSows it with a fine fescue shade mix at 2.3 kg per 92.9 m², halved when overseeding |
| Steep or erosion-prone share | Adds 50% seed on that share (editable) |
| Spring seeding or poor soil | Nothing automatic: pick the high end of the range with a custom rate |
| Seed from the bag label | Choose “Custom rate from the seed label” and enter the rate for your job |
How much area does a bag cover?
Coverage per bag = bag weight ÷ seeding rate. A 20 lb bag of tall fescue at 6 lb per 1,000 ft² covers about 3,333 ft² of new lawn, or twice that when overseeding.
| Bag | Tall fescue | Kentucky bluegrass | Perennial ryegrass | Bermudagrass (hulled) |
|---|---|---|---|---|
| 3 lb | 500 ft² | 1,500 ft² | 600 ft² | 3,000 ft² |
| 7 lb | 1,167 ft² | 3,500 ft² | 1,400 ft² | 7,000 ft² |
| 20 lb | 3,333 ft² | 10,000 ft² | 4,000 ft² | 20,000 ft² |
| 50 lb | 8,333 ft² | 25,000 ft² | 10,000 ft² | 50,000 ft² |
| Bag | Tall fescue | Kentucky bluegrass | Perennial ryegrass | Bermudagrass (hulled) |
|---|---|---|---|---|
| 1 kg | 34 m² | 102 m² | 41 m² | 205 m² |
| 5 kg | 171 m² | 512 m² | 205 m² | 1,024 m² |
| 10 kg | 341 m² | 1,024 m² | 410 m² | 2,048 m² |
| 20 kg | 683 m² | 2,048 m² | 819 m² | 4,096 m² |
The calculator also suggests the mix of common bag sizes that leaves the least left over. Sizes and prices vary by brand and store, so pick your bag size under “Bag size”.
Worked examples
New tall fescue lawn, 5,000 ft², 50 lb bagsNew tall fescue lawn, 465 m², 22.7 kg bags
Area to seed 5,000 ft² · Job New lawn (bare soil) · Grass type Tall fescue · Waste / overage 5 % · Bag size 50 lbArea to seed 464.52 m² · Job New lawn (bare soil) · Grass type Tall fescue · Waste / overage 5 % · Bag size 22.7 kg
- Seed needed: 31.5 lbSeed needed: 14.29 kg
- Bags (50 lb each): 1Bags (22.7 kg each): 1
- Fewest bags (3–50 lb sizes): 20 lb + 10 lb + 3 lbFewest bags (1–20 kg sizes): 10 kg + 5 kg
- Straw mulch (about 1 bale per 1,000 ft²): 5Straw mulch (about 1 bale per 93 m²): 5
Overseeding a thin Kentucky bluegrass lawn, 3,000 ft², 7 lb bagsOverseeding a thin Kentucky bluegrass lawn, 279 m², 3.2 kg bags
Area to seed 3,000 ft² · Job Overseeding a thin lawn · Grass type Kentucky bluegrass · Waste / overage 5 % · Bag size 7 lbArea to seed 278.71 m² · Job Overseeding a thin lawn · Grass type Kentucky bluegrass · Waste / overage 5 % · Bag size 3.2 kg
- Seed needed: 3.2 lbSeed needed: 1.43 kg
- Bags (7 lb each): 1Bags (3.2 kg each): 1
- Seeding rate used: 1 lb per 1,000 ft²Seeding rate used: 4.9 g/m²
Three bare patches (30, 20 and 15 ft²), half of them shadedThree bare patches (2.8, 1.9 and 1.4 m²), half of them shaded
Area to seed 30 ft² · Job Patch repair (bare patches) · Grass type Bluegrass + perennial ryegrass (85/15) · Shaded part of the area 50 % · Waste / overage 5 % · Bag size 3 lbArea to seed 2.79 m² · Job Patch repair (bare patches) · Grass type Bluegrass + perennial ryegrass (85/15) · Shaded part of the area 50 % · Waste / overage 5 % · Bag size 1.4 kg
- Seed needed: 0.3 lbSeed needed: 0.13 kg
- Bags of bluegrass + perennial ryegrass (85/15) (3 lb each): 1Bags of bluegrass + perennial ryegrass (85/15) (1.4 kg each): 1
- Bags of shade mix (3 lb each): 1Bags of shade mix (1.4 kg each): 1
- Shade mix (fine fescue + ryegrass): 0.2 lbShade mix (fine fescue + ryegrass): 0.08 kg
Steep bank of perennial ryegrass, 800 ft², all erosion-proneSteep bank of perennial ryegrass, 74.3 m², all erosion-prone
Area to seed 800 ft² · Job New lawn (bare soil) · Grass type Perennial ryegrass · Steep or erosion-prone part 100 % · Waste / overage 5 % · Bag size 7 lbArea to seed 74.32 m² · Job New lawn (bare soil) · Grass type Perennial ryegrass · Steep or erosion-prone part 100 % · Waste / overage 5 % · Bag size 3.2 kg
- Seed needed: 6.3 lbSeed needed: 2.86 kg
- Seeding rate used: 5 lb per 1,000 ft²Seeding rate used: 24.4 g/m²
- Bags (7 lb each): 1Bags (3.2 kg each): 1
Includes 50% extra seed for the steep ground.
Common mistakes
- Using the new-lawn rate to overseed. Twice the seed doesn't give twice the lawn. Crowded seedlings compete and the stand comes in weaker (UMass).
- Buying “variety not stated” seed or mixes with annual ryegrass for a permanent lawn. Nebraska Extension recommends certified (blue-tag) seed with named cultivars.
- Seeding the wrong season: cool-season grass in late spring, or warm-season grass in fall.
- Skipping soil contact. Rake or roll the seed into the top ¼ in of soil, and keep it moist until it germinates.
- Measuring the whole yard without taking out beds, the patio and paths.
Checked against
Each case below is re-run against the calculator by our automated test suite.
| Case | Our result | Checked against | Result |
|---|---|---|---|
| 0.23 acre (10,018.8 ft²) at 6 lb per 1,000 ft² (label rate), no waste | 60.1 lb | InchCalculator.com grass seed calculator (worked example) | Match |
| 7,854 ft² at 2 lb per 1,000 ft² (label rate), no waste | 15.7 lb | Omni grass seed calculator (worked example) | Match |
| 5,000 ft² new tall fescue lawn at 10 lb per 1,000 ft² (label rate), no waste | 50 lb | Eartheasy grass seed calculator (worked example) | Match |
| Same 5,000 ft² lawn with our tall fescue rate, no waste | 30 lb | Eartheasy grass seed calculator (worked example) | Differs: Eartheasy and InchCalculator.com use 10 lb per 1,000 ft² for tall fescue. The extension guides cited here give 4–9, and we use 6. |
| Overseeding 1,000 ft² of Kentucky bluegrass, no waste | 1 lb | Nebraska Extension: overseeding rates | Match (half the bare-ground rate, within the 1–2 lb Nebraska gives) |
These checks use US products and units. Switch to imperial to see them.
Frequently asked questions
How much grass seed do I need per 1,000 square feet?
For a new lawn, about 2 lb of Kentucky bluegrass or 4–8 lb of tall fescue, and about half that to overseed (Rutgers, Nebraska Extension). Check the label for your blend.
How much grass seed for overseeding?
About half the new-lawn rate, for example 1–2 lb of Kentucky bluegrass or 3–4 lb of tall fescue per 1,000 ft² (Nebraska Extension).
How much seed for bare patches?
Use the full new-lawn rate, but only on the area of the patches. Add each patch with “+ Another area”.
Should I use more seed in shade?
No. Use a shade-tolerant mix, mostly fine fescue, at its normal rate (UMass: 4–6 lb per 1,000 ft²). The calculator sows the shaded share with that mix.
How much area does a 20 lb bag of grass seed cover?
About 3,300 ft² of new tall fescue lawn at 6 lb per 1,000 ft², or 10,000 ft² of new Kentucky bluegrass at 2 lb.
Sources & assumptions
The results are planning estimates, and the cost figures only use prices you enter. Product yields, densities and coverage rates vary, so check the label or ask your supplier, and follow local codes. Figures marked "approximate" or "rule of thumb" are general practice, not exact standards.
- Rutgers NJAES FS584: Seeding Your Lawn
- Rutgers NJAES FS990: Tall Fescue Varieties for New Jersey
- Nebraska Extension: Overseeding in the Fall
- Nebraska Extension (Lancaster County): Time for Fall Lawn Seeding
- Nebraska Extension: Improving Turf in the Fall (seeding rates for the North Central US)
- UMass Amherst: Seeding Rate Considerations
- University of Tennessee Extension W160-B: Turfgrass Establishment
- UF/IFAS ENH-03: Establishing Your Florida Lawn
See how we calculate and test our formulas and the changelog. Last updated 2026-10-08.
Reviewed by the MaterialWhiz Editorial Team. This estimate uses the assumptions shown in the calculator. Review the result against your supplier's product coverage and site conditions. Last reviewed: October 10, 2026. See how we calculate · Report a correction.