Garden Soil Calculator
Soil & OrganicMeasurements in, purchasing amount out
How the Garden Soil Calculator works
The calculator finds volume first, then applies the selected material’s estimated bulk-density range to show weight. Your suggested order adds 10% for settling, uneven ground, and small measurement errors.
Using your measurements
12 ft × 8 ft × (10 in ÷ 12) ÷ 27 = 2.96 cu yd
Density assumption: Garden soil blend · 1,300–1,800 lb/yd³
The full breakdown
How much garden soil a bed or raised frame actually takes
The math above is exact — length times width times depth, converted to cubic yards — but garden soil asks a question mulch and gravel don’t: are you filling a raised bed from the ground up, or topping over soil that’s already there? A new raised garden bed needs its full depth in soil; an in-ground border or vegetable garden usually only needs the top several inches turned over and enriched, so measure accordingly before you order.
For a raised bed, pick “Raised bed mix” from the variant list and the density shifts to a lighter, compost-heavy blend, which is what most raised-bed kits — metal ones included — are actually filled with. Bagged blends state volume on the bag, not weight, so compare cubic feet to cubic feet rather than converting to pounds.
One distinction is worth settling before you buy anything: garden soil and potting soil are not interchangeable. Garden soil is formulated to sit in open ground or a bottomless raised frame with drainage into the earth below; potting soil, or a dedicated container mix, is formulated to drain freely inside a sealed pot. Using garden soil where a container mix belongs is the single most common way a new gardener ends up with compacted, waterlogged roots — see the FAQ below for the full comparison.
Blend changes the weight, not the volume
Cubic yards needed stay the same no matter which blend you choose — only the weight estimate moves. A compost-heavy raised bed mix sits at the light end because organic matter is lower-density than mineral soil; a fifty-fifty topsoil-and-compost blend or a straight garden soil blend runs heavier.
| Garden Soil | Weight |
|---|---|
| Raised bed mix | 1,000–1,500 lb/yd³ |
| 50/50 topsoil & compost | 1,400–1,900 lb/yd³ |
| Container / potting mix | 500–900 lb/yd³ |
How deep to fill it
Fill depth depends on what you’re actually building, not one universal number. These are common starting points for the situations gardeners search for most.
| New raised bed, built from scratch | 10–12 in (25–30 cm) |
|---|---|
| Topping up a raised bed each season | 2–3 in (5–7.5 cm) of fresh mix |
| New in-ground border or vegetable garden | 6–8 in (15–20 cm), worked into existing soil |
| Vegetable beds, by root depth | 6–8 in (15–20 cm) for greens and herbs; 12 in (30 cm) or more for tomatoes and root crops |
| Containers and pots | Use a potting or container mix instead — see the FAQ |
Bagged vs. bulk
Bagged garden soil is the practical choice for a handful of raised beds, a raised-bed kit, or filling gaps around new plantings; bulk delivery is cheaper per yard once a project needs more than two or three cubic yards. A cubic yard is 27 cubic feet regardless of blend, so the bag count below is straightforward division, not a soil-specific figure.
- 27 × 1 cu ft bags ≈ 1 cubic yard
- 18 × 1.5 cu ft bags ≈ 1 cubic yard
- 13.5 × 2 cu ft bags ≈ 1 cubic yard
- 9 × 3 cu ft bags ≈ 1 cubic yard
A standard pallet holds roughly 60–75 bags of 1.5-cubic-foot garden soil, though exact counts vary by retailer and bag size.
Two ways to shortchange a new bed
Garden soil in a pot
Garden soil is denser and drains more slowly than a container mix, so in a pot it compacts around the roots and holds water long after a potting mix would have dried out. Save garden soil for open ground or a bottomless raised frame, and use a labeled potting or container mix for anything in a sealed pot.
Filling flush to the rim
A compost-rich raised bed mix settles noticeably in its first season as organic matter breaks down and loose fill compresses under rain and watering. Fill a few inches proud of the rim rather than dead level, and expect to top it up the following spring.
Garden soil, specifically
Garden soil questions people actually ask
Why add 10% to the calculated amount?
Extra material covers small dips, settling, spillage, and measurements that are not perfectly square. The calculated amount remains visible so you can compare both figures.
Are bag counts based on the same amount?
Both are shown. “Calculated” bags cover the measured volume; “Order” bags include the 10% allowance and round partial bags up to whole bags.
How accurate is the weight estimate?
Volume comes directly from your dimensions. Weight is a range because moisture, particle size, composition, and compaction change bulk density.
What is garden soil?
A blend of native or screened soil enriched with compost or other organic matter, sold for filling raised beds, borders, and in-ground planting areas. It differs from plain topsoil, which is mostly mineral soil, and from potting soil, which is formulated to drain inside a container.
Can I use garden soil in pots?
Not recommended on its own. Garden soil is denser than a potting mix and is designed to drain into the ground beneath it — in a sealed container it compacts and holds excess water around the roots. Use a labeled potting or container mix for pots, or cut garden soil substantially with perlite and compost if that’s all you have on hand.
What’s the difference between potting soil and garden soil?
Potting soil is a soilless or mostly-soilless mix — peat, coco coir, bark, and perlite — engineered to hold moisture while draining freely in a container. Garden soil contains actual mineral soil blended with compost, and is meant for open ground or a raised bed with drainage into the earth below. Using one where the other belongs is the most common container-gardening mistake.
What is organic garden soil?
Garden soil whose organic matter comes from compost, aged manure, or other natural material, with no synthetic fertilizer added — often certified or listed for organic growing, such as an OMRI listing in the US. It feeds soil life and holds moisture well, which suits vegetable beds. The label matters more than the word: “organic” on a bag is not regulated the same way everywhere, so look for the certification or listing.
What soil should I use for raised garden beds?
A raised bed mix or a fifty-fifty blend of topsoil and compost both work well — the goal is soil that holds moisture without compacting, with enough organic matter to feed the first season of plantings. Many gardeners blend their own from bulk topsoil, compost, and a coarse amendment like perlite or aged bark fines.
How do you prepare soil for a garden?
Clear existing sod and debris, loosen the top 6–8 in with a fork or tiller, work in 2–3 in of compost or garden soil, and rake it level. Test drainage and pH if the bed has never grown vegetables before, and amend based on the results rather than guessing.
How do you make garden soil?
Blend a mineral base — native soil or purchased topsoil — with roughly 25–35% compost by volume, plus a coarse material like perlite or coarse sand if the base is heavy clay. There is no single fixed ratio; the goal is soil that crumbles in your hand rather than compacting into a ball.
How do you improve garden soil?
Add organic matter every season — compost, aged manure, or leaf mold — rather than relying on one heavy application. Organic matter improves structure in both directions: it opens up dense clay and helps sandy soil hold moisture and nutrients longer.