CalcBrite

Gravel Calculator

Calculate how many cubic yards and estimated tons of gravel or stone you need for paths, driveways, patios and drainage, or how many bags.

Under 30 secondsShows every assumptionLast reviewed October 2026
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Your area

Area 1

ft
ft
in
½ in12 in
Example for gravel & stone: 3 in. An editable starting point, not a recommendation.
This area: 120 sq ft × 3 in = 1.11 cu yd of gravel & stone
Gravel & Stone

Material needed: 1.11 cubic yards

30 cu ft of gravel & stone · covers 120 sq ft at 3 in deep

How are you buying it?
Volume
1.11 cu yd
Estimated weight
≈ 1.52 tons
Estimate at 1.37 tons per cu yd: the loose, dry figure from the FHWA table (gravel, dry, average gradation (loose)). Stone type, moisture and compaction change it.
t / cu yd
We don’t round to an order size. Ask your supplier about minimums and delivery increments.
12 ft10 ft3 in deep
Drawn to scale · grid squares = 1 ft · front cut away to show the layer
Close-up · depth to scale3 in
3 in of gravel & stone on soil. Ruler marks every inch.
What it looks like
6 ft person
1.11 cu yd = 1 full cube of 3 × 3 × 3 ft + 11% of another, next to a person for scale.

How gravel volume converts to tons

Tons = cubic yards × density. We start from the FHWA design-manual table, which lists dry gravel of average gradation at 2,730 lb per loose cubic yard, about 1.37 tons, and the same gravel wet at 3,290 lb, about 1.65 tons2. Crushed stone, pea gravel and river rock differ, and the table itself allows a ±5% variation. If your supplier gives a figure, enter it under “Supplier’s figure” and the tonnage updates.

Why stone type and size matter

Round river-run gravel such as pea gravel never packs down completely; the pieces slip and slide, which makes it better as a ground cover than a walking surface. Angular crushed stone packs to a nearly solid surface and suits paths and patios with foot traffic, and smaller pieces are more comfortable underfoot6. Particle size and shape change both density and how deep you may want the layer, so ask your supplier what suits paths, driveways or drainage.

Compacted vs loose gravel

Gravel that’s compacted after spreading takes up less volume than the loose material you buy. In the FHWA table the same dry gravel weighs 3,280 lb per cubic yard in place but 2,730 lb loose, which means the loose load is about 20% bigger than the compacted layer it becomes2; paver bases are built from crushed rock compacted in layers for the same reason7. The calculator shows the loose-volume estimate without an allowance.

How deep, and for what

For a garden path, two inches is a practical minimum depth, and you’ll need about four inches if thick stones or pavers are set into it6. A paver patio sits on 4 to 6 inches of compacted crushed base7. The calculator starts at 3 inches as an editable example. Use Rectangle for paths and patios, Triangle or Circle for odd corners, or enter the area directly if you know it.

Worked example: path, 30 × 3 ft at 3 in deep

  1. Area = 30 × 3 = 90 sq ft
  2. Volume = 90 × 0.25 ft = 22.5 cu ft = 0.83 cu yd
  3. Weight ≈ 0.83 × 1.37 = 1.14 tons (estimate)
  4. In 0.5 cu ft bags: 22.5 ÷ 0.5 = 45 bags

Frequently asked questions

How much gravel do I need?

Area × depth gives the volume; divide cubic feet by 27 for cubic yards. Enter your path or patio size above for an instant answer.

How many tons of gravel do I need?

Multiply cubic yards by your gravel’s density. At the FHWA table’s 1.37 tons per cu yd for loose, dry gravel, 2 cu yd is about 2.7 tons. Ask your supplier for their figure; it replaces ours in the calculator.

How much does a cubic yard of gravel weigh?

It depends on stone type and moisture. The FHWA design-manual table lists dry gravel of average gradation at 2,730 lb per loose cubic yard and the same gravel wet at 3,290 lb. That is why tonnage here is always labeled as an estimate.

How many bags of gravel equal a yard?

A cubic yard is 27 cu ft, so it takes 54 bags of 0.5 cu ft or 27 bags of 1 cu ft.

Sources & assumptions

  • Volume = area × depth. Circles use π × r²; triangles use ½ × base × height.
  • 1 cubic yard = 27 cubic feet; 1 cubic foot = 28.3168 liters; 1 m³ = 1.30795 cu yd.
  • Bags are rounded up to whole bags from the exact, unrounded volume.
  • Weights are estimates from loose, dry unit weights in the FHWA 1988 design-manual table: gravel 1.37, sand 1.30, topsoil 0.81 tons per cu yd. Moisture and stone type change them; your supplier’s figure replaces ours. Mulch weight isn’t estimated.
  • No allowance is added for compaction, settling or waste, and no order size is suggested.
  • Prices are only what you enter. CalcBrite doesn’t store or estimate local prices.
  • Example depths are editable starting points taken from extension guidance cited in the sections above, not recommendations for your site.
  • Metric bag sizes are examples of retail sizes (40–80 L); aggregates in metric markets are often sold by weight, so use Custom with the liters printed on the bag.

Sources

  1. Guide to the SI, Appendix B.8: cubic yard, cubic foot and short ton factors, NIST Special Publication 811.
  2. Table 6-12, Shrink/Swell Factors for Common Materials (loose and in-situ unit weights), Federal Highway Administration, Federal Lands Highway Project Development and Design Manual, Chapter 6 (September 1988); reproduced in Ohio DOT Technical Memo GE-65, Earthwork Factors (2008) — loose weights in lb per cubic yard: gravel, dry, average gradation 2,730 (wet 3,290); sand, dry 2,590 (wet 3,230); topsoil 1,620 (in place 2,430); earth loam, damp 2,360. Table notes a ±5% variation.
  3. Proper Mulching Techniques (Tree Care Basics infosheet), University of Illinois Extension; Sarah Vogel & Jenny Lee; modified March 2024 — recommended depth 2 to 4 inches; composted materials 2–3 in, coarse mulches 3–4 in; keep mulch at least 4 inches from the trunk; a 3-foot radius ring is the maximum for most trees.
  4. Mulching Landscape Trees, Penn State Extension; David R. Jackson; updated April 12, 2018 — 2 to 4 inches on well-drained soils, less on poorly drained; fine or double-shredded mulch 1 to 2 inches; keep mulch away from the trunk so the root flare shows; pull back 3–5 in from young trees, 8–10 in from mature trees.
  5. Planting and Mulching Trees and Shrubs (fact sheet), University of New Hampshire Extension; Cathy Neal — two to three inches deep, out to the drip line; pull the mulch back a few inches from the trunk; “volcano mulching” can kill the plant.
  6. Gravel Pathways in the Garden, University of California Master Gardeners, Contra Costa County; Earlene Millier; August 4, 2011, reissued March 2, 2020 — two inches is a practical minimum depth; allow four inches if thick stones or pavers are incorporated; river-run gravel never packs down, angular gravel packs to a nearly solid surface.
  7. 10-Step Guide to Installing Pavers, hosted by Oregon State University Extension Service (2011 document) — excavation depth = base (4 to 6 inches) + sand bedding (1 inch) + paver thickness; base of crushed rock such as ¾-minus, compacted in layers (retail or trade listing).
  8. Lawn Establishment, Penn State Extension; updated September 19, 2025 — a minimum of 4 to 6 inches (firmed or settled depth) of good-quality topsoil for good turf; till at least 4 inches.
  9. Improving a Struggling Lawn and Repairing Damage, University of Maryland Extension; updated March 16, 2026 — about ¼ to ¾ inch of topsoil or compost can usually be put on turf without smothering the crown.
  10. Timberline 2 cu. ft. Pine Bark Mini Nuggets Bagged Mulch, The Home Depot (retail listing) — example of the 2 cu ft bag size used as the default (retail or trade listing).
  11. Rindenmulch grob 0-40 mm, 60 l, Hornbach (retail listing, Germany) — example of a 60 L metric bag (retail or trade listing).
  12. Decorative garden bark, 1 × 80 litre bag, B&Q (retail listing, UK) — example of an 80 L metric bag (retail or trade listing).
Last reviewed:
October 2026
Last updated:
October 11, 2026
Calculator version:
1.0
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