Soil Volume Calculator
Calculate how much soil you need for raised beds, garden plots, and containers. Get volume in cubic feet, cubic yards, and bags needed.
About this calculator
This calculator turns a bed footprint into a purchasing decision. It multiplies length by width by depth, first switching your entered depth in inches over to feet so all three dimensions share a unit, to arrive at cubic feet, then divides by 27 to express the same volume in cubic yards, since bulk soil is almost always priced and delivered by the yard. From there it works out three ways to actually buy that soil: how many 1-cubic-foot bags you'd need, how many 2-cubic-foot bags (priced here at 60% more per bag to reflect real garden-center pricing, since larger bags cost less per unit volume but more per bag), and what a bulk delivery would run at your entered cost per yard.
The bag counts are rounded up, because a bed does not care that you only needed 8.3 bags — you still have to buy 9. The comparison exists because the crossover point between bagged and bulk soil is not obvious at a glance: a small container garden is almost always cheaper in bags, while anything over roughly a cubic yard usually favors bulk delivery once you account for the per-bag markup. The one assumption worth flagging is that this treats your bed as a simple rectangular prism at a uniform depth — it does not account for settling, which typically reduces loose soil volume by 10-20% within the first season, or for irregular bed shapes like L-shapes or curved borders, which you'd need to break into separate rectangles and sum.
Inputs
Results
Total Volume
32 cu ft
≈ 6 bathtubs
How to Use This Calculator
- Measure your raised bed or garden plot and enter the length and width in feet.
- Enter the desired soil depth in inches — most vegetables need at least 12 inches of root space.
- Input the cost per 1 cubic foot bag and the bulk cost per cubic yard so you can compare purchasing options.
- Read the Total Volume (cu ft and cu yd) to understand how much soil you need.
- Use the 1 cu ft Bags Needed or 2 cu ft Bags Needed values to plan your trip to the garden center, or compare against the Bulk Delivery Cost.
How the result changes with Bed Length
| Bed Length | Total Volume |
|---|---|
| 4 | 16 cu ft |
| 6 | 24 cu ft |
| 12 | 48 cu ft |
| 20 | 80 cu ft |
What each input means
- Bed Length
- Length of the raised bed or garden area in feet.
- Bed Width
- Width of the raised bed or garden area in feet.
- Soil Depth
- Desired depth of soil in inches. Most vegetables need 12 inches.
- Cost per 1 cu ft Bag
- Price per 1 cubic foot bag of garden soil or potting mix.
- Bulk Cost per Cubic Yard
- Cost per cubic yard if purchasing bulk soil delivery.
How this is calculated
Worked example, using the default values
- Identify Input Parameters4 parametersBed Length = 8, Bed Width = 4, Soil Depth = 12, Cost per 1 cu ft Bag = 6 = 5 input(s) provided
- Calculate Total VolumeTotal Volume32 = 32
- Calculate Cubic YardsCubic Yards1.19 = 1.19
- Calculate VolumeVolume = cubicFeet906.14 = 906.14
Engine last updated . Checked against 1 independently-derived test — how we verify calculators. Built by Paul Gunder, a software engineer, not a licensed financial, medical, or legal professional.
Frequently Asked Questions
Why does the calculator show three different total costs?
Garden soil is sold in at least three common formats — small bags, larger bags, and bulk delivery by the yard — and the per-unit price differs sharply between them. Showing all three side by side lets you see the actual dollar trade-off for your specific volume instead of guessing which format is cheaper for a bed your size.
Should I fill my raised bed all the way to the top with soil?
Most gardeners leave an inch or two of headroom below the top edge so mulch or watering doesn't spill over, and account for the fact that loose soil settles noticeably after the first watering and over a season. If precision matters, plan for slightly more volume than the raw bed dimensions suggest and expect to top off the bed later.
Does this account for soil compaction or settling over time?
No — the volume figure is a snapshot calculation from your bed's dimensions at the moment of filling, not a prediction of how the soil will behave afterward. Freshly delivered or bagged soil is loose and typically settles by 10-20% within the first few waterings, so many gardeners order slightly extra or plan a top-off pass.
How is cubic yards different from cubic feet for buying soil?
They're the same volume expressed in different units — one cubic yard equals 27 cubic feet — but bulk soil suppliers price and deliver by the yard, while bagged soil at garden centers is priced by the cubic foot. Converting between the two lets you compare a bulk delivery quote directly against a stack of bags at the register.
When does bulk delivery make more sense than buying bags?
Bulk delivery typically becomes cheaper once you need somewhere around a cubic yard or more, because bagged soil carries a packaging and handling markup per bag that bulk pricing avoids. For a single small raised bed the convenience and lack of a delivery minimum usually make bags the practical choice even if the per-unit price is a bit higher.
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