Soil Volume Calculator
Find how much soil or mulch you need for a rectangular bed or planter. Enter length, width, and depth in feet, plus the bag size in cubic feet. You’ll get total volume and number of bags.
FAQ
- What if my bed isn’t a rectangle?
- Use an approximate length and width that would cover the same area, or break the area into rectangles and add the volumes.
- Where do I find bag size?
- Bags often show volume in cubic feet (e.g. 1.5 or 2). If only weight is given, you can look up typical density or use a similar product’s cubic feet.
- Should I order extra?
- Yes. Soil compacts and depth can vary. Round up to the next whole bag or add about 10% to be safe.
- Can I use this for mulch?
- Yes. Use the same formula: length × width × depth for volume, then divide by bag size for number of bags.
How Much Soil or Mulch Do I Need?
For a rectangular bed or planter, the amount of soil or mulch you need is length × width × depth, all in the same units. In feet, that gives volume in cubic feet. Divide that by the size of one bag (also in cubic feet) to get how many bags to buy.
Home improvement calculators like this one help you avoid buying too much or too little. Depth matters a lot: a few inches for mulch is common; raised beds might need a foot or more of soil. Check bag labels for volume — many are 1.5 or 2 cubic feet.
Real beds aren’t always perfect rectangles. You can approximate with an average length and width, or split odd shapes into rectangles and add the results. Ordering a little extra is wise for compaction and uneven depth.
Also try our Paint Needed Calculator for home projects.
People Also Ask
- How much soil do I need for a raised bed?
- Can I use this calculator for mulch?
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- What depth of mulch do I need?
Last updated: February 2026