Mulch & Soil Calculator — Bags vs Bulk with Delivery Costs
Turn bed measurements into a purchase plan. Compare whole bags with the bulk quantity your supplier actually sells, including delivery fees.
Example inputs only — replace them with your own measurements and prices.
Your result
Enter your details and calculate. Results and assumptions appear here.
How this calculation works
Rectangular bed volume = length × width × depth. Add the chosen percentage allowance. Bag count rounds volume ÷ bag volume up to a whole bag. Bulk purchase rounds up to the supplier increment. One cubic yard = 27 cubic feet = 0.764554857984 m³. One litre = 0.001 m³. Cost = purchase quantity × unit price + delivery.
Assumptions and limitations
Estimates one rectangular bed, not a sloped terrain survey. No soil density, weight, quality, tax, labour or vehicle-load limit is inferred. Extra allowance and depth are chosen by you. Bagged and bulk material may differ in quality. All prices must use the same currency.
Sources and verification
Conversion reference: NIST SI measurement guidance. WebToolzHub is not affiliated with these organisations.
How much mulch or topsoil do I need?
Measure the length and width of a rectangular bed and choose the depth you intend to add. Enter the labelled volume of one bag, its price, the bulk price and any delivery charges. The calculator rounds bags to whole units and bulk material to the increment your supplier sells, then compares the two purchase totals.
US example: 30 ft by 5 ft at 3 inches
The unadjusted volume is 30 × 5 × 3 ÷ 12 = 37.5 cubic feet. Adding the sample 10% allowance gives 41.25 cubic feet, or about 1.528 cubic yards. At 2 cubic feet per bag, you need 21 bags. At 3 per bag with no delivery charge, the bag total is 63. If bulk material costs 50 per cubic yard, is sold in half-yard increments and costs 35 to deliver, the order rounds up to 2 cubic yards and totals 135. Bags are 72 cheaper in this example; your local quotes may reverse the result.
UK example: metres, centimetres and litres
A 4 m by 2 m bed with a 5 cm added layer needs 0.4 cubic metres before any allowance. That is 400 litres, so eight 50-litre bags cover the calculated volume. If the bulk supplier sells only 0.25 cubic metre increments, the purchase rounds up to 0.5 cubic metres. Compare the cost of that purchased quantity, rather than pricing only the exact 0.4 cubic metre requirement.
Compare equivalent material before buying
Use the same currency for every price: for example, all pounds or all dollars. Include the delivery charge for each option, and check whether quoted prices include tax. A lower delivered price does not establish equal quality. Mulch, screened topsoil and compost are different products; compare the grade and intended use as well as the volume. A bag described by weight cannot be converted accurately to volume without a suitable density value.
Frequently asked questions
How many cubic feet are in a cubic yard?
There are 27 cubic feet in one cubic yard. A 2-cubic-foot bag is therefore 2/27 of a cubic yard. To buy at least one cubic yard using only those bags, round 13.5 up to 14 bags.
Can I use this as a soil calculator?
Yes, for the geometric volume of a rectangular layer. It does not model compaction, moisture, density or weight. Set any extra allowance deliberately and confirm fill requirements with your supplier.
What if my bed is irregular?
Split it into rectangles and calculate them separately. Add the required volumes before rounding the final order; adding individually rounded bag or bulk quantities can buy more than necessary.
Does the sample depth suit every plant?
No. Depth is an input for your project, not a plant-care recommendation. Enter the additional layer you need, allowing for existing material, and follow guidance appropriate to your plants and material.
Can I save or change units?
Download CSV saves the results and assumptions. Changing units resets example measurements, so replace them with your own values and recalculate. No account is needed.
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