A soil calculator tells you exactly how many cubic feet, cubic yards, and bags of soil you need to fill any raised bed or garden plot. Whether your bed is rectangular, circular, or L-shaped, enter the dimensions below to get an instant volume estimate — no math required. The tool also breaks down your soil mix by component and shows cost estimates so you can budget your garden project accurately.
Raised Bed Soil Estimator
Adjust the percentage of each component — must total 100%.
Soil Volume Breakdown
Soil Mix Components
How to Use the Soil Calculator
Filling a raised bed with the wrong amount of soil is a common and costly mistake. Too little and your plants will be root-bound; too much and you end up hauling bags back to the store. This soil calculator removes all the guesswork by computing the exact volume of soil you need based on your bed's shape and dimensions, then converting that number into cubic yards and bags so you can shop with confidence.
Step 1: Choose Your Bed Shape
Click one of the three shape buttons — Rectangular, Circular, or L-Shaped. The input fields update automatically to match the selected shape. Rectangular is the most common shape for raised beds. Circular beds are popular for herb gardens and decorative plantings. L-shaped beds fit corner spaces and wrap around garden features.
Step 2: Enter Your Dimensions
For a rectangular bed, enter the length, width, and depth. For a circular bed, enter the diameter and depth. For an L-shaped bed, enter the overall bounding rectangle (length and width) and then the dimensions of the rectangular cut-out in the corner. Depth is entered in inches (or centimeters in metric mode) since most gardeners measure bed depth in inches. If you prefer meters, toggle the unit switch at the top — all labels and calculations update automatically.
Step 3: Enter the Number of Beds
If you are building multiple identical beds, increase the bed count. The soil calculator multiplies the volume of one bed by the total number and displays combined totals in the results. This is perfect when installing a series of matching raised beds across a garden, allotment, or community plot.
Step 4: Review Volume and Bag Counts
The results show your total soil volume in cubic feet, cubic yards, and bag counts for both 1 cubic foot and 2 cubic foot bags. Use the bag counts to plan your trip to the garden center, or use the cubic yards figure to order bulk soil from a landscape supplier — bulk is almost always cheaper for larger projects. Enter your local prices in the optional price fields to get an instant cost comparison between bags and bulk.
Step 5: Plan Your Soil Mix (Optional)
Toggle on "Show mix" to break down your total volume into individual components. The classic raised bed formula is one-third topsoil, one-third compost, and one-third perlite or vermiculite — but you can adjust the sliders to match any recipe. The calculator shows exactly how many cubic feet of each ingredient you need, so you can purchase each component separately or mix to order.
Frequently Asked Questions
Is this soil calculator free to use?
Yes, this soil calculator is completely free with no signup required, no paywalls, and no limits on the number of beds you can calculate. All math runs in your browser — your project details are never sent to any server.
Is my data private when I use this tool?
Absolutely. Every calculation runs locally in your browser using client-side JavaScript. No measurements, bed counts, or personal data are ever transmitted to a server. Your information stays completely private on your device.
How much soil do I need for a 4x8 raised bed?
A 4×8 foot raised bed that is 12 inches (1 foot) deep needs 32 cubic feet of soil, which equals approximately 1.19 cubic yards. That works out to about 32 one-cubic-foot bags or 16 two-cubic-foot bags. If your bed is 6 inches deep, you need half that amount — 16 cubic feet or about 0.59 cubic yards.
What is the recommended depth for a raised bed?
Most vegetables thrive in a raised bed 12 inches (30 cm) deep — enough for healthy root development. Root vegetables like carrots and parsnips prefer 18–24 inches. For herbs and shallow-rooted crops, 6 inches is sufficient. Strawberries and flowers typically need 8–12 inches of good growing medium.
What soil mix should I use in a raised bed?
A classic raised bed mix is one-third topsoil, one-third compost, and one-third coarse perlite or vermiculite. This blend drains well, holds moisture, and provides rich nutrition. Some gardeners use a 60/40 split of topsoil and compost. Avoid using garden soil straight from the ground — it compacts in raised beds and restricts root growth.
How do I calculate soil for an L-shaped raised bed?
An L-shaped bed is treated as a large rectangle minus the inner rectangle that has been removed. Enter the overall length and width of the bounding rectangle, then enter the length and width of the corner cut-out. The calculator subtracts the cut-out area and multiplies the remaining footprint by the depth to give you the exact volume needed.
How many bags of soil do I need?
Divide the total cubic feet of soil needed by the bag size. A 1 cubic foot bag covers exactly 1 cubic foot, while a 2 cubic foot bag covers 2 cubic feet. Most bulk bags of potting mix sold at garden centers are 1 or 2 cubic feet. The calculator shows both sizes so you can compare based on what's available at your local store.
Is it cheaper to buy bulk soil or bags?
Bulk soil (purchased by the cubic yard) is almost always cheaper for large projects — typically $30–80 per cubic yard delivered, versus $6–12 per cubic foot in bags. For one small 4×4 raised bed, bags are fine. For three or more full-size beds, a bulk delivery from a landscape supplier will save significant money.