Topsoil Bag Calculator
How many bags of soil for a raised bed, a lawn repair or a planter, and what one bag fills.
Quick estimating rule of thumb
For topsoil bags: area (sq ft) × depth (in) ÷ 12 = cubic feet, then divide by the bag volume. A 40 lb bag holds about 0.75 cubic feet, so a cubic yard is roughly 36 bags. Bagged soil is screened and dried, so it is lighter than the same soil delivered loose. Add 10% for settling.
This topsoil bag calculator gives you a bag count rather than a volume, which is what you need when soil is going in the trolley rather than on a truck. Bagged soil is usually sold in 1, 1.5 or 0.75 cubic foot bags, and the tool covers all of them.
Switch to Bags I have to check whether what you have already bought will actually fill the bed, a common and expensive surprise with raised beds, which swallow far more soil than people expect.
For bulk yardage and delivery, see the topsoil calculator. For the compost half of a bed mix, use the compost calculator.
Raised beds swallow bags
This is where bag counts shock people. A 4 ft × 8 ft raised bed 12 inches deep holds 32 cubic feet: that is 32 bags of 1 cubic foot, or about 21 bags of 1.5. At 18 inches deep the same bed takes 48 cubic feet. Two beds and you are past a cubic yard and well into bulk-delivery territory.
A 4 ft × 4 ft bed at 12 inches is a more manageable 16 cubic feet, about 16 bags. Filling the bottom third of a deep bed with coarse organic matter (branches, leaves, the hügelkultur approach) cuts the bought soil considerably, though the level will drop over the first season as it breaks down.
What one bag covers on the ground
Spread rather than filled, a 1 cubic foot bag covers 12 square feet at 1 inch deep, 6 square feet at 2 inches, or 4 square feet at 3 inches. Levelling a lawn or top-dressing after seeding usually wants a quarter to half an inch, where one bag goes a long way, about 24 to 48 square feet.
Laying a new lawn is different: 3 to 4 inches of topsoil over the graded sub-soil means roughly 2.5 to 3.5 bags of 1 cubic foot per 10 square feet. A 500 square foot lawn area needs about 5 to 6 cubic yards (125 to 165 bags), which is a delivery, not a trolley.
Soil, compost and the bed mix
Do not fill a raised bed with topsoil alone. It compacts and drains poorly in a confined box. A common mix is roughly 60% topsoil, 30% compost and 10% coarse material such as perlite or sharp sand. Work the bag counts out separately for each component and add them.
Bagged "garden soil" and "raised bed mix" are already blended, so buy those by total volume and skip the maths. They cost more per cubic foot than plain topsoil, which is the trade for not mixing three products in a wheelbarrow.
Where bulk takes over
It takes 27 bags of 1 cubic foot to make a cubic yard, 18 bags of 1.5, or about 36 of the 40 lb bags; see bags per cubic yard for every size. Bagged soil is roughly two to four times the price per yard of bulk, so the crossover comes early, often around 10 to 15 bags. Bulk soil is also usually better quality for the money, since screened topsoil from a landscape yard is graded, whereas bagged soil varies widely by brand.
The counter-argument is access: bulk arrives as a pile on your drive and has to be barrowed, and a cubic yard is roughly 1.1 tons. If the beds are round the back and up a step, bags may still win.
Frequently asked questions
How many bags of soil do I need?
Multiply length × width × depth in feet for cubic feet, then divide by the bag size. A 4 ft × 8 ft bed 1 foot deep is 32 cubic feet: 32 bags of 1 cubic foot or about 21 bags of 1.5.
How many bags of soil for a 4x8 raised bed?
At 12 inches deep, 32 cubic feet: about 32 bags of 1 cubic foot, 21 bags of 1.5, or 43 bags of 0.75. At 6 inches deep it halves to about 16 cubic feet.
How many bags of topsoil are in a cubic yard?
27 bags of 1 cubic foot, 18 bags of 1.5 cubic feet, or 36 bags of 0.75 cubic foot.
How much does a bag of topsoil cover?
A 1 cubic foot bag covers 12 square feet at 1 inch deep, 6 square feet at 2 inches, or 4 square feet at 3 inches.
How many bags of soil for a 4x4 raised bed?
At 12 inches deep that is 16 cubic feet, about 16 bags of 1 cubic foot or 11 bags of 1.5.
Is bagged or bulk soil cheaper?
Bulk is substantially cheaper past roughly 10 to 15 bags, often two to four times cheaper per cubic yard, and usually better graded. Bags win when access is awkward or the quantity is small.
How much does a bag of topsoil weigh?
A 1 cubic foot bag of screened topsoil weighs about 40 lb dry, and noticeably more if it has been sitting in the rain.
Can I fill a raised bed with topsoil only?
It is better not to. Topsoil alone compacts in a confined bed and drains poorly. Aim for roughly 60% topsoil, 30% compost and 10% coarse material, or buy a ready-blended raised bed mix.
How deep should soil be for a new lawn?
Three to four inches of topsoil over graded sub-soil. That is about 1 cubic yard per 80 to 100 square feet, which is bulk territory for anything but a small patch.
How many bags of soil to level a lawn?
Levelling usually needs a quarter to half an inch. One 1 cubic foot bag covers 24 to 48 square feet at that depth, so a 500 square foot lawn takes roughly 10 to 20 bags.
What is the difference between topsoil and garden soil?
Topsoil is plain screened soil. Bagged garden soil and raised bed mix are topsoil already blended with compost and amendments, more expensive per cubic foot but ready to use.
Should I buy extra bags of soil?
Yes, about 10%. Fresh soil settles noticeably in the first few weeks of watering, and raised beds in particular drop an inch or two.
How many bags of soil fit on a pallet?
Usually 50 to 70 bags depending on size, roughly 1.5 to 2.5 cubic yards. If you are approaching a pallet, price a bulk delivery first.