How much topsoil or compost do I need?
Fill a raised bed, top up a border or lay a bed for new turf — enter the area and depth and get the volume in cubic metres and litres, the rough weight, and how many bulk or small bags to buy. Soil settles, so buy a touch over. Free, no sign-up.
A guide, not a guarantee. We work out the volume from the area and depth, then the weight using a typical density for the material (about 1.5 t/m³ for topsoil, much less for compost and bark, which are bought by volume). A loose "bulk" or "dumpy" bag holds roughly 0.6 m³ — suppliers vary, so check before you order. Soil settles, so for a new bed order a touch over and top it up after the first rain. Nothing you type leaves your browser.
Area, depth, and how it's sold.
Volume comes first. Area times depth gives the volume in cubic metres — that's what soil and compost are really sold by, even when it comes in bags. A new raised bed or border usually wants 300 mm or more; topping up an existing bed needs 50–100 mm.
Weight depends on the material. Topsoil is heavy — about 1.5 tonnes per cubic metre — so a small bed is still a real load. Compost and bark are much lighter and fluffier, which is why they're sold by the litre. We use a typical density for the material you pick to estimate the weight.
Bags or bulk. A loose "bulk" or "dumpy" bag holds roughly 0.6 cubic metres (suppliers vary, so check). For more than a bag or two, a loose load tipped on the drive is usually cheaper and much less lifting than dozens of small bags — we'll flag it when the bag count gets silly.
Allow for settling. Fresh soil and compost settle once they're watered in, dropping by an inch or more in a deep bed. Order a little over and top it up after the first good rain rather than ending up short.
What this leaves out. A sub-base or drainage layer, a weed membrane, edging or sleepers for a raised bed, and any feed or grit you're mixing in.
Keep every garden job in one place.
Stead remembers your garden's measurements, the materials you chose and when each job was done — so the next project starts with the numbers already to hand.