Bagged vs bulk
Bulk is cheaper for this job
With these prices and $100 delivery, bulk starts to win at about 0.8 cu yd (about 0.6 beds of this size). Bulk cost rises in half-yard steps.
Prices used in this comparison
Typical price (estimate, checked Oct 2026): $7.50–$12.00 per 1.5 cu ft bag of raised bed soil
Use a price like 7.50.
Typical price (estimate, checked Oct 2026): $30.00–$70.00 per cu yd of garden soil mix
Use a price like 30.00.
Typical price (estimate, checked Oct 2026): $50.00–$150.00 per delivery
Use a price like 50.00.
3 cu yd × $30.00–$70.00 + $50.00–$150.00 delivery = $140–$360
Delivery is one fee for the bulk order, and it carries over to the topsoil, gravel and mulch calculators. Bags are raised bed soil in 1.5 cu ft bags, whichever way you chose to buy above. Bulk uses the per cu yd garden soil mix price.
How it works
The formula
round bed: π × (diameter ÷ 2)² × depth (in) ÷ 12
total cu ft = cu ft per bed × beds × (1 + settling)
cu yd = total cu ft ÷ 27
bags = total cu ft ÷ 1.5, round up
Assumptions
- Settling is 10% by default. Fresh, loose soil sinks after the first few waterings, and 10 to 20% is a rule of thumb, not a measured figure. Choose 0% if you will top up later.
- Bags are counted by the volume printed on the bag (1.5 cu ft is a common size), not the weight. Check your bag; a different size changes the count.
- Bulk is rounded up to the half cubic yard, which is how most suppliers sell it.
- Mix it yourself uses equal parts topsoil, compost and coarse sand by volume, a recipe from Iowa State University Extension; its other option is about 70% topsoil and 30% compost, and other extension services suggest different blends. Topsoil comes in 0.75 cu ft bags and compost in 1 cu ft bags, each rounded up. The aerator is not priced here, because the product and the share vary.
Worked example
Two 4 × 8 ft beds, 12 in deep, 10% for settling
- One bed: 8 × 4 × 12 ÷ 12 = 32 cu ft
- Two beds with settling: 32 × 2 × 1.10 = 70.4 cu ft
- In yards: 70.4 ÷ 27 = 2.61 cu yd, which orders as 3 cu yd in bulk
- In bags: 70.4 ÷ 1.5 = 46.9, round up to 47 bags
- As a mix: 23.5 cu ft of topsoil is 32 bags, 23.5 cu ft of compost is 24 bags, plus 23.5 cu ft of coarse sand
- At $9.75 a bag (the middle of our typical range): 47 × $9.75 = $458.25
Common sizes
| Bed | Depth | Cu ft | 1.5 cu ft bags | Cu yd |
|---|---|---|---|---|
| 4 × 4 ft | 8 in | 10.7 | 8 | 0.40 |
| 4 × 4 ft | 10 in | 13.3 | 9 | 0.49 |
| 4 × 4 ft | 12 in | 16.0 | 11 | 0.59 |
| 4 × 8 ft | 8 in | 21.3 | 15 | 0.79 |
| 4 × 8 ft | 10 in | 26.7 | 18 | 0.99 |
| 4 × 8 ft | 12 in | 32.0 | 22 | 1.19 |
| 3 × 6 ft | 8 in | 12.0 | 8 | 0.44 |
| 3 × 6 ft | 10 in | 15.0 | 10 | 0.56 |
| 3 × 6 ft | 12 in | 18.0 | 12 | 0.67 |
| 4 × 12 ft | 8 in | 32.0 | 22 | 1.19 |
| 4 × 12 ft | 10 in | 40.0 | 27 | 1.48 |
| 4 × 12 ft | 12 in | 48.0 | 32 | 1.78 |
One bed, no extra for settling. Bag counts are rounded up. Multiply the cu ft by your number of beds and add settling before you buy.
Questions people ask
How many bags of soil for a 4x8 raised bed?
A 4 × 8 ft bed filled 12 in deep takes 32 cu ft, which is 22 bags of 1.5 cu ft. With 10% for settling it is 35.2 cu ft, or 24 bags.
How deep should a raised bed be?
6 to 12 in of soil is enough for most vegetables and herbs. Tomatoes and root crops like carrots and parsnips do better with 10 to 12 in or more. Deeper beds take much more soil: every extra 6 in on a 4 × 8 ft bed adds 16 cu ft.
What soil mix should I use?
Buy a bagged raised bed mix, or blend your own. Iowa State University Extension suggests equal parts topsoil, compost (or well-rotted manure) and coarse sand, or about 70% topsoil and 30% compost. Plain topsoil alone packs down hard in a bed, and compost alone is too rich. Recipes vary, so treat these shares as a starting point.
How much does a yard of soil fill?
One cubic yard is 27 cu ft. That fills 0.84 of a 4 × 8 ft bed at 12 in, or 27 sq ft of bed floor at 12 in deep and 54 sq ft at 6 in. In 1.5 cu ft bags a yard is 18 bags.
Can I fill the bottom of a raised bed with something else?
Yes, in a deep bed. Logs, branches, leaves or cardboard can fill the bottom to save soil, but they rot and sink over a year or two, so plan to top up. Roots need about 6 to 12 in of real soil on top. Filling a 4 × 8 ft bed's bottom half with other material cuts the soil from 32 to 16 cu ft. A layer of gravel does not improve drainage, so skip it.