Buying soil, compost and mulch is where most garden projects go over budget, usually because it is hard to picture how much a cubic yard really is. These free calculators turn your bed sizes into exact quantities, in cubic feet, cubic yards and bags, so you buy the right amount the first time.
Every calculator explains its formula, includes worked examples, and allows for the way fresh soil settles. Start with the tool that matches your project below, or follow the step-by-step guide further down the page.
Soil & Mulch tools
- Soil CalculatorEnter the size and depth of your area to get cubic yards, cubic feet and bag counts.Open tool →
- Raised Bed Soil CalculatorFind how much soil fills one or more raised beds, and how much of each ingredient your mix needs.Open tool →
- Compost CalculatorWork out how much compost to spread or mix in, by area and depth.Open tool →
- Mulch CalculatorGet cubic yards, cubic feet and bag counts of mulch for any bed and depth.Open tool →
- Soil Bag CalculatorConvert a soil volume into bag counts and compare with bulk.Open tool →
- Mulch Bag CalculatorConvert a mulch volume into bag counts and compare with bulk.Open tool →
Soil & Mulch guides
Soil & Compost
How to Build a Raised Garden Bed (DIY Plans & Cut List)
Build a 4x8 raised garden bed step by step with a full materials and cut list, wood choices, filling tips and raised garden bed ideas.
Soil & Compost
25 Raised Garden Bed Ideas (Materials, Heights & Layouts)
25 raised garden bed ideas by material, height, layout, built-in features and budget, with pros and cons, a materials comparison and tips for every situation.
Soil & Compost
Metal Garden Beds: Are They Safe, Pros & Cons, and How to Set Up
Metal raised garden beds explained: are galvanized beds safe for vegetables, do they get too hot, types of metal beds, metal vs wood, buying tips, and how to fill tall…
Soil & Compost
Garden Edging Ideas: 10 Ways to Edge Beds (Free to Permanent)
Garden edging ideas from a free spade-cut edge to steel, brick, stone and wood: pros and cons, installation steps, and tips for vegetable gardens and raised beds.
Soil & Compost
How Much Soil Do I Need for a Raised Bed? (Charts & Calculator)
Work out exactly how much soil a raised bed needs, with charts for common sizes, settling allowance, the best soil mix, and how to fill tall beds for less.
Soil & Compost
Garden Lime: When and How to Use It (and When Not To)
What garden lime does, how to tell if your soil needs it, calcitic vs dolomitic lime, how much to apply, the best time to lime, and the mistakes to avoid.
Where to start
- Filling a new raised bed? Use the raised bed soil calculator. It splits the total into topsoil, compost and an aerating ingredient.
- Topping up beds or leveling ground? The soil calculator handles rectangles, circles and other shapes.
- Feeding existing beds? The compost calculator works out how much compost to spread each year.
- Mulching beds and paths? The mulch calculator covers beds, paths and tree rings.
- Deciding between bags and bulk? The soil bag calculator and mulch bag calculator show the break-even point for your local prices.
Allow for settling. New beds sink as soil settles and compost breaks down. Adding 10 to 20 percent to your soil order saves a second delivery. Our guide on why raised bed soil sinks explains why.
Frequently asked questions
How much soil do I need for a 4×8 raised bed?
About 29 cubic feet for a bed 11 inches deep, or roughly 34 cubic feet with an allowance for settling. That is about 1.25 cubic yards.
How many bags of soil are in a cubic yard?
A cubic yard is 27 cubic feet: 18 bags of 1.5 cubic feet, or about 14 bags of 2 cubic feet.
How deep should mulch be?
About 2 to 3 inches on planting beds and 3 to 4 inches on paths. Keep mulch a few inches away from stems and trunks.
Is bulk soil cheaper than bags?
For larger jobs, usually. Bags are often cheaper below about a cubic yard once delivery fees are counted. The bag calculators show the break-even point for your prices.