Sod and Grass Seed Calculator
Sod and grass seed calculator — enter your lawn dimensions to get the number of turf (sod) rolls and the weight of grass seed you need, based on a sowing rate you can adjust. For new lawns and overseeding. Runs in your browser.
Sod and Grass Seed Calculator
How to Use the Sod & Grass Seed Calculator
Measure the lawn
Enter the length and width in metres.
Set the seed rate
~35 g/m² new; ~half for overseeding.
Set roll coverage
Usually ~1 m² per turf roll.
Read the order
See turf rolls and seed weight; add ~5% extra.
Seed or Turf, and How Much
Laying a new lawn starts with one practical question — seed or turf — and immediately leads to a second: how much. This calculator answers the quantity for both at once. From your lawn’s length and width it works out the area, then converts that into the number of turf rolls you would need and the weight of grass seed you would need, using a sowing rate you can adjust. That lets you compare the two approaches on the same measurement before you commit to either.
For seed, the typical sowing rate for a brand-new lawn is around 35 grams per square metre, so a fifty-square-metre lawn needs roughly 1.75 kilograms; overseeding a thin existing lawn uses about half that. Setting the rate matters — too sparse and the lawn comes through patchy and weed-prone, too dense and seedlings compete and damp off. Different grass mixes recommend anywhere from 25 to 50 grams per square metre, so the rate here is adjustable and you should check the bag. For turf, a standard roll covers about one square metre, so the roll count is close to the area itself, and it is wise to add about five percent for trimming edges and fitting around beds and curves.
The seed-versus-turf decision comes down to time, money and patience. Turf gives an instant, usable lawn and establishes fast, but it costs considerably more and is perishable — it must be laid within about a day of delivery before it heats up and yellows. Seed is far cheaper, stores well, and offers a wider choice of grass varieties, but it takes weeks to establish and is at the mercy of weather and birds in the meantime. Whichever you choose, the groundwork is the same and decisive: clear weeds, cultivate and level the topsoil, then firm and rake to a fine tilth before sowing or laying. Sow or turf in spring or early autumn when the soil is warm and moist, water new turf daily until it roots, and the lawn will establish well. Treat the figures here as a confident starting order, round up, and check your product’s specific rate and roll size. As ever, the calculation runs entirely in your browser, so your measurements stay private.
Turf is an instant lawn you must lay within a day; seed is a cheaper, patient one — the same square metres, two very different jobs.
10 Facts About New Lawns
New lawns from seed are sown at about 35 g/m².
Overseeding an existing lawn uses about half that.
A standard turf roll covers about 1 m².
Turf gives an instant lawn; seed is cheaper.
Sow seed in spring or autumn for best results.
Lay turf within 24 hours of delivery.
Water new turf daily until it roots.
Rake and firm the soil before seeding or turfing.
Buy 5% extra turf for trimming edges.
This calculator runs in your browser — nothing is uploaded.
Frequently Asked Questions
- Multiply your lawn area by the sowing rate. For a brand-new lawn the typical rate is around 35 grams per square metre, so a 50 square metre lawn needs about 1.75 kilograms of seed. Overseeding an existing lawn uses roughly half that rate. The calculator works out the area and the weight for whatever rate you set.
- Divide your lawn area by the area one roll covers. A standard turf (sod) roll covers about one square metre, so a 50 square metre lawn needs about 50 rolls. The calculator rounds up, and it is wise to add around five percent extra for trimming the edges and fitting around curves.
- Turf gives you an instant, usable lawn and establishes quickly, but costs more and must be laid promptly. Seed is much cheaper and offers more grass-variety choice, but takes weeks to establish and is vulnerable to weather and birds in the meantime. The right choice depends on budget, timeframe and how soon you need to use the lawn.
- About 35 grams per square metre is a common rate for a new lawn from seed; some mixes recommend 25 to 50 depending on the grass type, so check the bag. For overseeding a thin existing lawn, use roughly half. Setting the rate too low gives a patchy lawn; too high wastes seed and can cause overcrowding.
- Spring and early autumn are ideal, when the soil is warm and moisture is reliable, giving fast germination and rooting. Turf can be laid across a longer season as long as it is watered well, but avoid sowing seed in the heat of summer or in frost. Soil temperature matters more than the calendar date.
- Clear weeds and debris, dig or rotavate the topsoil, level it, then firm and rake to a fine tilth. A firm, level, weed-free bed is the single biggest factor in a successful lawn, whether seeding or turfing. Adding a pre-turf or pre-seed fertiliser helps establishment.
- As soon as possible — ideally within 24 hours, because rolled turf heats up and yellows quickly. If you cannot lay it at once, unroll it in a shaded spot and keep it moist. Seed has no such urgency and stores well in a cool, dry place, which is one of its practical advantages.
- For turf, add about five percent for trimming edges and fitting around beds, paths and curves. For seed, buying a little extra is cheap insurance against a patchy area needing a second sowing. The calculator gives the base quantity; round up when ordering.
- It is a reliable estimate for a rectangular lawn. Irregular shapes, slopes and heavy edge-trimming increase the real requirement, and seed rates vary by mix, so treat the figure as a starting point and check your specific product’s recommended rate and roll size.
- Completely free, with no account or limit. It works offline once the page has loaded and collects no data.
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