Measure your lawn, choose your seed rate, and get an exact seed quantity — with visual coverage, bag count, and leftover estimate.
Split your lawn into zones with the same dimensions for per-section seed estimates.
Check your seed bag for the recommended rate.
Coverage
vs recommended max
Density
Standard
Recommended Seed Quantity
≈ 0 kg
Total Area
600 ft²
Per Section
600 ft²
Seed / Section
3.0 lbs
Bag Coverage
5,000 ft²
Bags Needed
1
25 lb bags
Remaining Seed
22.0
lbs leftover
Overseeding Rate
2.5 lb/1000ft²
Lower density for existing lawns
New Lawn Rate
5.0 lb/1000ft²
Higher density for bare soil
Lawn seed coverage is the relationship between your lawn's total area, the seed application rate, and the coverage stated on the seed bag. The core formula is simple: Total area ÷ 1,000 × application rate = total seed needed. For example, a 5,000 ft² lawn with a 4 lb per 1,000 ft² rate requires 20 lbs of seed.
Our grass seed calculator takes your length, width, and number of sections to determine total square footage — then multiplies by the rate you choose. It also factors in bag weight to tell you exactly how many bags to buy and how much seed you'll have left over.
New lawn seeding (bare soil) requires a higher application rate — typically 4–6 lbs per 1,000 ft² — because you're establishing a full stand of grass from scratch. Overseeding or reseeding an existing lawn uses a lower rate (2–3 lbs per 1,000 ft²) since you're thickening what's already there. Always check your specific grass variety's recommendation.
The application rate is the single biggest factor in seed coverage. Too little seed and you'll get thin, patchy growth. Too much and you waste money while creating overcrowded seedlings that compete for nutrients. Your seed bag's label is the gold standard — follow it.
For rectangular lawns, simply multiply length × width. For irregular shapes, break the lawn into smaller rectangles or circles and add the areas together. Our lawn area calculator handles the math for you — just enter the dimensions and the number of sections.
Use a measuring tape or a laser distance measurer for accuracy. If your lawn has curved borders, measure the widest and longest points and subtract obvious non-lawn areas (driveways, patios, garden beds).
A 40 ft × 25 ft front lawn = 1,000 ft². For a new lawn at 5 lb/1,000 ft², you'd need 5 lbs of seed. If your bag is 10 lbs, you'd buy 1 bag and have 5 lbs left over — enough to patch thin spots later.
Seed bag rates are calibrated for that specific grass variety's germination rate, seed size, and growth habit. Following them ensures proper establishment, reduces waste, and gives you the best chance of a thick, healthy lawn. Factors like soil quality, sunlight, and watering also affect coverage — when in doubt, lean toward the higher end of the recommended range for new lawns.
For a new lawn, most grass varieties call for 4–6 lbs per 1,000 ft². For overseeding, 2–3 lbs per 1,000 ft² is typical. Always check your seed bag — different species (e.g., tall fescue vs. perennial ryegrass) have different recommended rates.
Break the lawn into simple shapes (rectangles, circles, triangles), calculate the area of each, and add them together. Use the "number of sections" input if you have multiple lawn zones with the same dimensions.
Overseeding is best if you have an existing lawn that's thin or patchy — it thickens the turf without starting over. If you're establishing grass on bare soil or after a renovation, use the new lawn rate for better establishment.
Divide your total seed requirement by the bag weight, then round up. For example, if you need 22 lbs and bags are 25 lbs, you'll need 1 bag with 3 lbs leftover.
Yes. Large-seeded varieties like tall fescue need more weight per area than small-seeded ones like Kentucky bluegrass. The application rate on the bag accounts for this — always use the rate specific to your seed variety.
Application rate, seed size, germination percentage, and the condition of your soil. Better soil prep and proper watering can improve germination, meaning you can sometimes use the lower end of the recommended rate.
Absolutely. Select "Acres" from the unit selector. The calculator will convert your length and width accordingly and display area in acres and square feet.
Seed is sold in fixed bag sizes, so you often buy slightly more than you need. The leftover estimate helps you plan — you can use extra seed to patch thin spots or store it for next season (keep it cool and dry).