Garden soil is sold by volume, but gardens are measured by area, and that mismatch is why people order too little and pay for a second delivery. An in-ground bed, a border, and a lawn all need soil, but they need it in very different depths: a bed may need 30 cm of good soil, while a lawn topdressing needs only a few millimetres. This calculator handles those garden jobs directly. Choose the job, enter length, width and depth, and it returns litres, cubic metres, bags, and bulk tonnes.
This tool is deliberately different from a raised-bed calculator. A raised bed is a box with fixed walls, and its volume comes from the box size. An in-ground bed has no walls: you dig into the existing ground, improve it, or build up a planting area on top of it, and the depth is the depth of soil you want to add or replace. A lawn topdressing is thinner still: a few millimetres of compost spread over grass to feed it and level small bumps. Using the wrong shape for these jobs gives the wrong order.
Here is a worked example for a bed. A bed 4 metres long and 2 metres wide with 30 cm of soil to add covers 8 square metres, and 8 times 0.30 metres gives 2.4 cubic metres, which is 2,400 litres. That is 60 bags of 40 litres, or 48 bags of 50 litres, or about 2.88 bulk tonnes at the assumed density of 1.2 tonnes per cubic metre. The same area as a lawn topdressing at 5 mm needs only 0.04 cubic metres, which is 40 litres: one bag. The depth, not the area, drives the order.
Settling is the reason the tool shows a second, larger figure. Fresh soil contains air, and the first watering and rain settle it noticeably, so a bed that looks full on delivery day sits lower a week later. Ordering 15 percent extra covers normal settling for most garden soils. If you are filling a bed that will be planted at once, fill it, water it well, and top it up before planting rather than planting into soil that will sink under the plants.
Bags suit small jobs and bulk suits large ones, and the crossover is roughly one cubic metre. Below that, bags are easier to carry, store, and spread, even though they cost more per litre. Above that, bulk delivery is usually cheaper and creates less plastic waste, but you need a place for a delivery pile and a way to move the soil, such as a wheelbarrow and a clear path. Tell the supplier what the soil is for: vegetable beds, lawns, and borders need different mixes, and cheap fill soil is not planting soil.
Measure the area honestly. For an irregular bed, split it into rectangles and add the areas together. For a lawn, measure the whole lawn area, not just the worn patches, because topdressing is spread evenly. Measure depth from the finished soil surface you want, not from the top of any edging, and remember that existing soil counts: if the bed already has 15 cm of decent soil and you want 30 cm, you only need to add 15 cm.
Remember that this is a planning estimate, not a professional quote. Bulk density varies by product and moisture: wet soil weighs more per cubic metre than dry soil, so treat the tonne figure as a guide and confirm it with your supplier. Very large areas, slopes, and drainage problems deserve a site visit from a landscaper. For a normal garden job, show your numbers to the supplier and ask them to confirm bags or bulk tonnes before delivery.