Generated on: June 17, 2026 at 05:24 PM

Grass Seed Calculator

Inputs

Lawn area200 m²
Grass typeTall fescue
PurposeNew lawn

This is an estimate based on standard seeding rates for each species. Actual requirements vary by cultivar, seed quality (germination rate), soil preparation, climate, and seeding method. Follow the rate printed on the seed bag, which is calibrated to the specific product.

Generated with OneCalc · https://onecalc.app/en/lifestyle/grass-seed

Lifestyle

Grass Seed Calculator

Estimate how much grass seed is needed for a new lawn or overseeding project based on lawn area, grass species, and purpose.

Inputs

≥ 0 m²

Results

Enter a value to see results.

Details

A New lawn of 200 m² with Tall fescue requires approximately ... of seed (rate: ... lb per 1000 sq ft).

Embed this calculator

Preview

Paste this code into your page to show the calculator.

Share this calculation

Anyone who opens this link sees your values already filled in.

Grass seed requirements are calculated from three inputs: the area to cover, the species being planted, and whether the project is a new lawn or overseeding into existing turf. Each species has a recommended seeding rate, expressed in pounds of seed per 1000 square feet, that is based on seed size, germination percentage, and the density needed for good coverage.

The rate × area method

The seeding rate from the seed bag label is the baseline. To find the total seed needed, the area is converted to units of 1000 square feet, then multiplied by the rate:

seed (lb)=area (sq ft)1000×rate (lb/1000 sq ft)×purpose factor\begin{aligned} \text{seed (lb)} &= \frac{\text{area (sq ft)}}{1000} \times \text{rate (lb/1000 sq ft)} \times \text{purpose factor} \end{aligned}

The purpose factor is 1.0 for a new lawn seeded onto bare soil, and approximately 0.5 for overseeding an existing turf. To convert to metric, 1 lb equals 0.454 kg and 1 m² equals 10.764 sq ft.

Worked example

A 200 m² lawn to be seeded with tall fescue as a new lawn:

area (sq ft)=200÷0.09290304=2152.8 sq ftseed (lb)=(2152.8÷1000)×8=17.22 lbseed (kg)=17.22×0.45359=7.81 kg\begin{aligned} \text{area (sq ft)} &= 200 \div 0.09290304 = 2152.8 \text{ sq ft} \\ \text{seed (lb)} &= (2152.8 \div 1000) \times 8 = 17.22 \text{ lb} \\ \text{seed (kg)} &= 17.22 \times 0.45359 = 7.81 \text{ kg} \end{aligned}

The same 200 m² overseeded with Kentucky bluegrass at 3 lb per 1000 sq ft with a 0.5 factor gives 1.46 kg of seed.

New lawn vs overseeding

When seeding bare soil, seed has direct contact with the ground and no competition from established grass. The full label rate is appropriate to achieve uniform, dense coverage. When overseeding into existing turf, the established plants already provide some cover. A reduced rate of roughly 40–50% of the new-lawn rate fills gaps and increases density without excess waste.

Seeding rates by grass type

Different species vary widely in seed size and germination speed, which drives the rate differences.

Kentucky bluegrass seed is very fine and slow to germinate (14–30 days), so a low rate of 2–4 lb per 1000 sq ft is standard. Tall fescue and perennial ryegrass are coarser, germinate in 5–10 days, and require 6–9 lb per 1000 sq ft to establish a dense stand quickly. Bermuda grass is a warm-season species often planted by seed in the south; rates of 1–2 lb per 1000 sq ft apply because the seed is fine and establishment from seed is slower in any case.

These rates are general guides. The seed bag label from a specific cultivar is calibrated to the germination percentage of that lot and should take precedence.

For related garden area projects, see the Mulch & Garden Soil Calculator.

Frequently Asked Questions (FAQ)

How much grass seed do I need?

The amount depends on three factors: the area to cover, the grass species, and whether the seed is going onto bare soil (new lawn) or into an existing turf (overseeding). New lawns need the full package-label rate; overseeding typically uses 40–50% of that. For example, tall fescue at 8 lb per 1000 sq ft on 200 m² (about 2153 sq ft) requires roughly 7.8 kg of seed.

Why does overseeding use a lower rate?

When seeding bare soil, seeds have good contact with the ground and a low chance of shading from existing plants, so the full rate is needed to achieve dense coverage. When overseeding into existing turf, established grass provides some cover and competes for resources, so a lower seed rate (about half) avoids waste while still thickening the lawn. Using the full rate on an existing lawn does not produce proportionally better results and adds unnecessary cost.

What are the typical seeding rates by grass type?

Seeding rates vary considerably by species. Kentucky bluegrass germinates slowly and is very fine, so only 2–4 lb per 1000 sq ft is recommended. Tall fescue and perennial ryegrass are coarser and germinate quickly, requiring 6–9 lb per 1000 sq ft. Bermuda seed is very fine and relatively inexpensive, but establishment from seed (as opposed to sod or plugs) uses 1–2 lb per 1000 sq ft. These are general guides; the seed bag label from the cultivar and region is the most reliable reference.

Disclaimer

This is an estimate based on standard seeding rates for each species. Actual requirements vary by cultivar, seed quality (germination rate), soil preparation, climate, and seeding method. Follow the rate printed on the seed bag, which is calibrated to the specific product.

Recommended Next

Mulch & Garden Soil Calculator

Calculate the volume of mulch or garden soil needed to cover a bed at a chosen depth, in cubic yards, cubic feet, or m³, and the number of bags to buy.

 Learn more
Solar Panel Sizing Calculator

Enter monthly kWh usage, peak sun hours, and system losses to find the right rooftop solar system size, panel count, annual output, and estimated cost.

 Learn more
Paint Coverage Calculator

Calculate paint needed, cans to buy, total cost, and leftover from surface area, coverage rate, number of coats, and can size.

 Learn more

200+ calculators · 10 languages · 100% free

Was this calculator helpful?

No

How can we improve this calculator?
Powered by OneCalc ↗