Raised Bed Calculator

How Much Soil Do You Need? Try Our Free Raised Bed Soil Calculator

Planning a new raised bed or container garden? Not sure how many litres (or tonnes!) of soil you’ll need? You’re not alone — every week, thousands of UK gardeners ask the same thing.

That’s why we’ve built a simple, easy-to-use Soil Volume Calculator, made just for home growers. Enter your bed or container’s length, width, and depth, then choose your bag size. We’ll instantly calculate:

• How many litres of soil you need
• How many bags (20L, 30L, 50L or 100L)
• Bulk soil estimate in tonnes

No more guessing, over-ordering, or running out halfway through!

What to Fill It With: Soil Mix Guide for Raised Beds

Knowing how much you need is just the first step. For a productive, healthy bed, what goes into the soil matters just as much. We recommend the 60/30/10 rule:

• 60% topsoil – Forms the structural base of your bed
• 30% compost – Boosts nutrients and organic matter for strong growth
• 10% potting mix or perlite – Improves drainage and keeps soil light

This mix gives your plants the perfect balance: structure, nutrition, drainage, and microbial activity.

Pro Tip: After filling, top your bed with a thin layer of mulch or compost to help retain moisture and protect your soil.