About this site
Gravel and Mulch Calculator is a single purpose tool built to answer one recurring landscaping question: how much material does a specific bed, path, or yard actually need. Instead of a generic volume calculator that treats every material the same, this site's calculator uses a separate density figure for each of nine common landscaping materials, wood mulch, cedar mulch, 3/4 inch gravel, pea gravel, topsoil, garden soil, compost, sand, and river rock, so the weight and bag estimates reflect the material actually being ordered.
What the free calculator does
Enter the shape of the area, rectangle, circle, or several zones added together for an L-shaped bed or a multi-section yard, along with the desired depth, and the calculator returns cubic yards, cubic feet, an estimated number of 2 cubic foot and 3 cubic foot bags, an approximate wheelbarrow load count, and an estimated weight in tons, all updated instantly without reloading the page.
The free Depth Cheat Sheet
Alongside the calculator, a one page printable cheat sheet covers recommended depths by project type and typical coverage figures, available after providing an email address, meant to sit next to a garden plan or shopping list while planning a project.
The Landscape Material Planner
For anyone planning a larger or multi zone project, The Landscape Material Planner is a paid reference document covering pre-calculated coverage tables for all nine materials, a density and weight reference, a method for measuring irregular beds, a budget grid organized by zone, a delivery day checklist, and a comparison of bagged versus bulk material with the approximate point where bulk becomes the cheaper option.
Independence and accuracy
This site is not affiliated with any mulch, gravel, or soil supplier. Density figures used throughout the site and its calculator are standard landscaping industry averages; actual weight can vary with moisture content and the specific product a supplier sells, which is why the site consistently describes its weight figures as estimates rather than exact measurements.
Questions
Anything unclear about the calculator, the cheat sheet, or the planner can be sent through the contact page.
How to measure a project before using the calculator
Start with the finished outline of the bed, path, or work area, not the rough disturbed soil around it. Measure in feet when possible, because most landscape material coverage is easiest to check from square feet and depth in inches. A 25 ft tape measure is enough for most residential beds. For long paths, a 100 ft tape, marking paint, stakes, and string give cleaner measurements.
For a rectangle, measure length and width at two places. If the two width readings differ, use the larger number for ordering or split the area into two smaller rectangles. For a circle, measure across the widest point to get the diameter. For a curved bed, place stakes every 4 ft to 6 ft along the long edge, then divide the bed into short rectangles or triangles and add the sections.
- Clear loose leaves, branches, and stored items before measuring, because they hide the true edge.
- Write each zone on paper with a name, such as front walk left bed, driveway strip, or rear play area.
- Record depth separately from area. Area is square feet, depth is inches, and material volume comes from combining both.
- Add 5 percent to 10 percent only when edges are uneven, the base is rough, or some material will be lost during spreading.
A practical measuring tolerance is about 1 inch for small beds and about 3 inches for larger yard areas. A larger error can change the order by several bags or by a fraction of a cubic yard, especially at depths above 3 inches.
Tools, working depths, and field dimensions
The calculator gives material quantity, but the job still needs a few site dimensions checked before ordering. Depth should be measured after the base is shaped, not before excavation. If old mulch is being refreshed, measure the remaining mulch and subtract it from the target finished depth. If 1 inch remains and the target is 3 inches, only 2 inches of new mulch is needed.
| Job condition | Typical field check | Useful order allowance |
|---|---|---|
| Fresh mulch on bare soil | 2 in to 3 in finished depth | About 5 percent extra for uneven soil |
| Mulch refresh over an old layer | 1 in to 2 in added depth | Little extra if the edge is clean |
| Decorative gravel over fabric | 2 in depth for most beds | 5 percent to fill low spots |
| Walkway gravel base | 3 in to 4 in compacted depth | 10 percent if compaction is expected |
| Soil or compost top dressing | 1/2 in to 1 in spread depth | Measure closely, thin layers multiply fast |
For spreading, a steel rake, square shovel, wheelbarrow, soil knife, gloves, and a 12 inch ruler are enough for most jobs. Check depth by pushing the ruler through the loose material at several points. On a 200 square foot bed, take at least six depth checks. On a 1,000 square foot yard section, take 15 to 20 checks so high and low areas are not missed.
Wheelbarrow size also matters when planning labor. A small residential wheelbarrow may carry about 3 cubic feet when comfortably loaded, while a larger contractor style wheelbarrow may carry closer to 6 cubic feet. A cubic yard is 27 cubic feet, so one cubic yard can mean roughly 5 to 9 wheelbarrow trips, depending on load size and how full each trip can be moved safely.
Frequent mistakes and how to recover
The most common error is mixing inches and feet. A depth of 3 inches is 0.25 ft, not 3 ft. If an order looks extremely large, check the depth entry first. A second common error is using the outside edge of a border rather than the inside fill area. A 4 inch border around a small rectangle can change the measured width by 8 inches, which is enough to affect bag count.
If too much material is delivered, do not spread it too deep to make it disappear. Mulch placed much deeper than 4 inches can hold excess moisture against plant crowns. Gravel placed too deep on fabric can become hard to rake level and may spill over edging. Instead, create a secondary use area, raise low spots, or store dry bagged material off the ground.
If too little material is delivered, measure the unfinished area before reordering. Do not estimate by eye from the remaining pile. Measure the bare or thin section, enter that zone alone, and order the shortfall. For bagged products, round up to the next full bag. For bulk delivery, ask for the smallest practical added amount and confirm whether a second delivery fee applies before placing the order.
Irregular depth is another problem. Rake the full area once, then check depth in a grid pattern. Move material from thick bands toward thin spots before opening more bags or ordering more bulk. For more troubleshooting points, see the calculator FAQ.
Special cases that need separate zones
Some projects should not be measured as one large shape. Split them into zones when the material type, depth, or base condition changes. A front bed may need 3 inches of mulch, while the narrow strip beside the driveway may need only 1 inch because old material is still present. These should be calculated separately and then added to the shopping list.
Sloped areas also need care. Measure the ground surface, not the flat map distance, when the slope is noticeable. For a short, steep bank, run the tape along the soil surface from top to bottom. If material tends to slide, use lighter lifts and check whether edging or plant roots will hold it in place before spreading the full depth.
Tree rings are another special case. Keep mulch pulled back a few inches from the trunk and calculate only the ring area that will actually be covered. For raised beds, calculate soil or compost by inside dimensions, not outside lumber dimensions. For paths with curves, divide the path into 5 ft or 10 ft length sections and use the average width of each section.
Wet material is heavier and may handle differently from the estimate. After rain, bulk soil, compost, and mulch can gain substantial water weight, which affects unloading and wheelbarrow work more than coverage. Plan shorter loads, protect turf along the route, and avoid dumping heavy wet material on soft lawn areas if rutting would be a problem.
Read next
- Compost calculator guide: Calculate how much compost to work into a vegetable bed, top dress a lawn, or blend into new planting soil, with typical depths and a worked example.
- Depth cheat sheet: Download the free one page Depth Cheat Sheet: recommended depths and coverage for mulch beds, paths, trees, vegetable gardens, and drainage areas.
- Sand calculator guide: Calculate how much sand a paver base, play area, or drainage layer needs, with typical depths, weight per cubic yard, and a worked example.