Mulch, Topsoil & Gravel Yardage
Turn areas and depth into yards and bags
Mulch, topsoil and gravel yardage FAQ
How deep should I make mulch or gravel?
For most garden beds, 2–3 inches of decorative mulch freshens the surface, while 3–4 inches helps with weed suppression. For gravel paths, 2–3 inches is common over a compacted base. Beds with shrubs and trees can use deeper mulch if crowns and stems are kept clear.
Can I mix mulch, soil and gravel in one calculation?
The volume maths is the same for each material type, so this tool will add them up fine. In practice it’s often easier to run separate summaries for mulch, topsoil and gravel so each delivery or bag count stays tidy on your order.
Is bulk delivery cheaper than bags?
For larger projects, bulk mulch, soil or gravel sold by the cubic yard is often cheaper per unit than bagged product, especially once you factor in time loading, unloading and dealing with bags. Small jobs or tight access might still favour bags even if they cost more.
How accurate are printed bag volumes?
Bag labels give a nominal volume, but real coverage can vary with moisture, compaction and grading. This calculator treats the bag volume as exact and then rounds up the bag count. If you are on the fence, a couple of extra bags are usually cheaper than a second trip to the store.
Can I use this for raised beds and planters?
Yes. For raised beds, measure the inside length and width and use the planned soil depth as the depth value. For tall containers, you might only calculate soil or compost for the top section that roots will use.
What if my areas are not rectangles?
Break curves and L-shapes into a couple of simple rectangles and treat each as an area. You can also trace a curve as if it were a rectangle (longest length and width) and let the rounding on yardage cover the small “wasted corners”.
How to use this mulch, topsoil and gravel yardage calculator
The goal is to stay simple: start with one rectangle, add a bag size, then tap + Add area if your project has more patches.
1. Pick US / Imperial or metric
Choose whether you measure in feet and inches or metres and centimetres. The labels on the area fields update automatically. Stick with one system for all measurements on a project.
2. Measure Area 1 fully
Area 1 is required. Measure the length and width inside any edging, then choose an average depth for mulch, soil or gravel. If the depth slopes a bit, just pick a middle number; yardage and bag counts are rounded so you have a little buffer.
3. Add more areas if you need them
Tap + Add area for each extra rectangle you want to include. You can add several areas on a single job until everything is covered. If you leave a whole area row blank, it is ignored in the maths.
4. Enter your bag volume
In US mode, bag volume is in cubic feet (for example 1.5, 2 or 3 cu ft). In metric mode, it switches to litres so you can type 40, 50 or 60 L, depending on your local bags. The calculator converts total volume into that unit and rounds up the bag count.
5. Read yards, meters and bags together
When you tap Calculate yards and bags, the summary shows:
- How many areas were counted.
- Total surface area in both ft² and m².
- Total volume in cubic yards and cubic meters.
- Bag count for your chosen bag volume, rounded up, plus a simple bulk yardage number.
It stays compact so you can screenshot it or copy the summary text into a message without editing.
6. Copy the summary into your quote or order
Use the Copy summary button to drop all the numbers into a note, email or quote request. That way you have the same figures when you compare prices, book delivery and actually spread the mulch, soil or gravel.
How the mulch, soil and gravel yardage maths works
Behind the scenes the calculator just follows the usual area × depth approach you would use on paper, then converts into the units suppliers talk in.
1. Area of each rectangle
For each rectangular area:
Area = length × width
In US mode, area is in square feet (ft²). In metric mode, it is in square metres (m²).
2. Depth in matching units
Depth is converted to feet or metres so it matches the area units:
- US: depth in feet = depth in inches ÷ 12
- Metric: depth in metres = depth in centimetres ÷ 100
3. Volume per area and total volume
Volume is area × depth:
Volume = Area × Depth
The calculator adds Area 1 and any extra areas to get a single total volume in either cubic feet (US) or cubic meters (metric).
4. Converting to cubic yards and cubic meters
US volumes use the standard:
1 cubic yard = 27 cubic feet
Metric volumes use:
1 cubic yard ≈ 0.7646 m³
The tool keeps both sides so you can talk “yards” with a US supplier or “m³” with plans or EU guides.
5. Turning total volume into bags
For bagged product:
- US: total cubic feet ÷ bag size (cu ft) = exact bags → rounded up.
- Metric: total cubic meters × 1000 ÷ bag size (L) = exact bags → rounded up.
Rounding up gives you a small margin so you don’t run out on the last corner of the last area.
References and further reading on mulch, soil and gravel volume
These resources use the same basic formulas for area, depth and cubic yards:
- Texas A&M AgriLife Extension — How much compost, soil or mulch? — length × width × depth and cubic yard examples.
- Iowa State University Extension — Amount of mulch needed for a garden bed — step-by-step bed and mulch calculations.
- The Calculator Site — How many cubic feet are in a yard? — confirms that 1 cubic yard equals 27 cubic feet.
- Bachman’s — Mulch calculator and bag guidance — examples turning total cubic feet into 2 cu ft or 3 cu ft bag counts.
- Lowe’s — Mulch and soil calculator — a retail example using area, depth and coverage logic for estimates.
Use this tool as a quick planner, then confirm final yardage and bag counts with your local supplier’s coverage charts and advice for the exact product you are ordering.