Gravel Calculator (2026)
Find out exactly how much gravel you need, in cubic yards, tons, bags and cost.
Calculate Your Gravel
Measure the longest side of the area in feet.
Measure the shortest side of the area in feet.
Driveways usually need 3 to 4 inches; garden paths 2 to 3 inches.
Type changes the guide note only. The math is identical for all three.
Leave blank for no cost estimate. Delivery fees are not included.
Order about 10% extra for settling and uneven ground. That extra is a guide suggestion only: it is NOT added into the results above, so add it yourself before ordering.
Bag count is rounded up to whole bags. Delivery, tax and spreading labour are not included in the cost estimate.
How the Gravel Calculation Works
First, multiply length by width to get the area in square feet. Then convert the depth from inches to feet, multiply by the area, and you have the volume in cubic feet. Divide by 27 to get cubic yards, because one cubic yard holds 27 cubic feet. Finally, multiply cubic yards by 1.4 to get tons, since this calculator uses a single disclosed density of 1.4 tons per cubic yard for every gravel type.
Volume (cu ft) = area x (depth in inches / 12)
Volume (cu yd) = volume (cu ft) / 27
Weight (tons) = volume (cu yd) x 1.4
Bags (50 lb) = round up (weight in lb / 50)
Cost = weight (tons) x price per ton
Worked Example: 20 by 10 Feet at 3 Inches Deep
With the default values, the area is 20 x 10 = 200 square feet. The volume is 200 x 0.25 feet = 50 cubic feet, which is 50 / 27 = 1.85 cubic yards. At 1.4 tons per cubic yard, that is 2.59 tons, or about 5,185 lb. Dividing by 50 lb gives 103.7, rounded up to 104 bags. At $45 per ton, the material cost is 2.59 x $45 = $116.67.
Gravel Coverage Table: Cubic Yards Needed
Use this table for a quick check before you measure. Find your area, then read across to your planned depth. For irregular shapes, measure the area in sections and add the sections together.
| Area | 2 inches deep | 3 inches deep | 4 inches deep | 6 inches deep |
|---|---|---|---|---|
| 100 sq ft | 0.62 cu yd | 0.93 cu yd | 1.23 cu yd | 1.85 cu yd |
| 200 sq ft | 1.23 cu yd | 1.85 cu yd | 2.47 cu yd | 3.70 cu yd |
| 500 sq ft | 3.09 cu yd | 4.63 cu yd | 6.17 cu yd | 9.26 cu yd |
| 1,000 sq ft | 6.17 cu yd | 9.26 cu yd | 12.35 cu yd | 18.52 cu yd |
Remember the 10% rule: the table shows the exact volume for a perfectly level area. Real ground is rarely perfect, so ordering about 10% extra covers settling and low spots. That extra is not built into the calculator results above.
Which Gravel Type Should You Choose?
Pea gravel is small, smooth and comfortable to walk on, which makes it a popular pick for paths, patios and play areas. Its rounded stones do shift underfoot, so it is less ideal for steep slopes or heavy vehicle traffic. Crushed stone has angular edges that lock together, giving a firmer surface that holds up well under cars, so it is the usual choice for driveways and parking areas. River rock is larger, rounded and decorative, and it works best as a visible top layer in garden beds and around landscaping rather than as a driving surface. All three use the same density in this calculator, so your choice affects looks and performance, not the quantity maths.
How Deep Should Gravel Be?
- Garden paths and walkways: 2 to 3 inches over landscape fabric is usually enough for foot traffic.
- Patios and seating areas: 3 inches gives a stable, comfortable surface that still drains well.
- Driveways: 3 to 4 inches of gravel over a compacted base layer. For heavy vehicles, a deeper compacted base matters more than extra top gravel.
- Drainage areas and French drains: depth depends on the trench, not the surface, so measure the trench cross-section instead of the surface area.
Bags or Bulk Delivery: Which Is Cheaper?
For small jobs under about 1 cubic yard, bags from a garden centre are convenient and easy to carry, but you pay far more per ton. Bulk delivery by the cubic yard or ton is almost always cheaper for driveways and larger areas, and the supplier tips it where you need it. The break-even point is usually around 1 to 2 cubic yards: if the calculator shows more than that, get a bulk quote before buying bags. Always confirm whether the quoted price includes delivery, because delivery fees can change the comparison completely.
Tips Before You Order
- Measure twice, in sections. Split L-shaped or curved areas into rectangles, calculate each one, and add them together.
- Compact in layers. For driveways, spread and compact in 2-inch layers rather than dumping the full depth at once.
- Use landscape fabric under paths. It stops weeds and keeps gravel from sinking into soft soil, which also keeps your depth honest.
- Edge it. Metal, timber or stone edging keeps gravel where it belongs and stops it spreading onto lawns.
- Check access. Make sure a delivery truck can reach the spot, or plan where the pile will sit and how far you will wheelbarrow it.
