Updated · Changes and corrections
Where the numbers come from
We use sources in this order and say on each page which one a figure is:
- The supplier’s own figure for the product. Weights per yard, prices and coverage charts, each stored with its URL and the date it was recorded.
- Standards and agency documents. Stone sizes from AASHTO M43 as reproduced in state DOT specifications, paver base from ICPI, playground surfacing from the CPSC, gravel road layers from the FHWA.
- Engineering handbooks. Caterpillar’s loose, bank and wet weights explain why figures differ; they are not product weights.
- General estimates. 105 lb/ft³ is a starting point only, used until you enter a supplier’s number. It was adopted from the default Omni Calculator uses; Caterpillar’s dry gravel weight supports it. See bulk density and weight.
Figures we derive
Some numbers on the site are arithmetic on those sources, and each page shows the inputs:
- Depth a coverage chart implies = the chart’s cubic feet per ton ÷ square feet per ton × 12.
- Weight a coverage chart implies = 2,000 lb ÷ (square feet × depth in inches ÷ 12) × 27, in lb per cubic yard.
- Pile size: a cone of the load’s volume standing at 32–36°, the natural slopes MSHA measured on a sand and gravel stockpile. Diameter = 2 × ∛(3 × volume ÷ (π × tan slope)).
- Pickup load = rated payload ÷ bulk density; its depth in the bed = that volume ÷ (box volume ÷ inside box height).
- Price per yard from a per-ton price = price per ton × the page’s reference weight ÷ 2,000.
How supplier prices are recorded
The gravel price list holds 64 list prices from 17 suppliers, recorded September 23–24, 2026, each one a reader can find on the supplier’s public price list or product page. Each is stored with its URL, the unit it was quoted in and the date it was recorded, and keeps that date until the price is recorded again. National estimate sites and prices that appear only after entering a ZIP code are left out of that list.
Other prices are recorded separately, each with its source and date: delivered prices by load in the dump truck load guide, bag prices in the bags versus bulk guide, one supplier’s per-ton decorative stone prices on the landscape rock calculator, and equipment rental rates in the driveway cost guide. Installed driveway costs come from named third-party cost guides and contractors, and the driveway cost guide labels each by type.
Per-ton and per-yard prices are kept apart on gravel prices, and a summary price says how many lists it rests on. Where a material page restates a per-ton price per yard, it uses the formula above.
How the pages are made
AI assistance was used across the site’s research and writing. AI tools read the supplier pages, specifications and manuals each page cites, extracted every figure with its URL and the date it was read, and drafted the text.
Where a source could be fetched automatically, scripts re-checked its figures against the source text, fetching the page or PDF and searching it for each number (with tools such as curl, pdftotext and grep). Some sites block automated requests; at the last check, on September 24, 2026, these were angi.com, cat.com, engineeringtoolbox.com, fromtheroad.ford.com, homedepot.com, homeguide.com and mulchpros.com, so figures from them were read from the page without that scripted re-check. The arithmetic is covered by automated tests, described under how calculations are checked.
Why AI: the pages rest on dozens of supplier price lists, product pages, specifications and manuals, and AI makes it practical to read and cross-check that many documents while keeping each figure tied to its source. The site’s one AI-generated image is the share card shown when the gravel density page is linked elsewhere; it is labelled as an AI-generated illustration on the image, in its alt text and in its file metadata. The charts are drawn by scripts from the data they show.
Volume comes first
For a rectangular area, volume = length × width × depth. For a circle, volume = π × (diameter ÷ 2)² × depth. For a known surface area, volume = area × depth. The calculator converts each input into meters before calculating, then sums the volumes of all areas.
In US units, length (ft) × width (ft) × depth (in) ÷ 324 gives cubic yards. In metric units, area (m²) × depth (cm) ÷ 100 gives cubic meters. For a walk-through with the calculator, see how to calculate how much gravel you need.
Bulk density and weight
Weight = purchase volume × bulk density. The initial value of 105 lb/ft³ is a general estimate, not a specification for pea gravel, crushed stone or any particular product. It converts to approximately 1,682 kg/m³. You can replace it with your supplier’s value or remove it to calculate volume only.
Bulk density includes the voids between particles. Do not substitute solid rock density. Moisture, particle shape and grading affect the result. Caterpillar’s earthwork tables list dry 1/4–2 inch gravel at 2,850 lb per loose cubic yard (105.6 lb/ft³), which supports the general estimate, the 105 lb/ft³ adopted from the default that Omni Calculator’s gravel reference uses. That page is named as provenance, not as a data source. The supplier’s product data should take precedence.
Material references, not universal densities
The pea gravel preset uses Lasalle Sand & Gravel’s published 2,700 lb per cubic yard (100 lb/ft³), a reference for one product, not a specification for every quarry. The calculator never fills in a price; cost uses the quote you enter. Supplier list prices are recorded separately on the material pages and gravel prices.
Source: Lasalle’s material weight and conversion table, recorded September 16, 2026. For comparison, South Bay Materials lists its 3/8 inch pea gravel at 2,440 lb per cubic yard. Differences between products are why your supplier’s value takes precedence. The other 9 presets are also single suppliers’ published weights. They and the other supplier weights per yard in our ledger are listed with their sources and recorded dates in the gravel weight per yard reference.
Choosing a preset sets bulk density. Editing that density marks the material as custom. Unit changes preserve the physical density; shared estimates preserve the selected reference and inputs. No reference in this tool constitutes an endorsement or supply relationship.
Known volume
If you already know your quantity, choose Known volume and enter cubic yards in US mode or cubic meters in metric mode. No depth is required. The same allowance, density, bag and cost calculations apply. Do not add a known volume and dimensions for the same material area, which would count it twice.
Extra allowance is explicit
Purchase volume = geometric volume × (1 + allowance ÷ 100). The default is 0%. The calculator does not select a waste or compaction percentage for you. Ask the supplier how a compacted design layer translates to loose material before ordering.
Units and conversion factors
| 1 foot | 0.3048 meters |
|---|---|
| 1 inch | 0.0254 meters |
| 1 cubic yard | 27 cubic feet |
| 1 pound | 0.45359237 kilograms |
| 1 US short ton | 2,000 pounds |
| 1 metric tonne | 1,000 kilograms |
See the NIST Guide to the SI conversion tables. Internal calculations retain precision; the main results are displayed to two decimal places. Supplier order increments are not automatically applied.
Bags and quoted costs
Volume bags = purchase volume ÷ volume per bag. Weight bags = estimated weight ÷ weight per bag. The calculator rounds the bag count up to a whole bag. A small numerical tolerance prevents floating-point conversion noise from adding a bag to an exact whole-bag result.
Cost = quantity × your unit quote + delivery. The quantity is cubic yards, cubic meters, short tons, tonnes or whole bags, depending on your selection. All cost fields use USD. Tax, labor, equipment, minimum orders and supplier rounding are excluded.
A reproducible example
15 ft × 8 ft × 4 in = 40 ft³ = 1.481481… yd³. At 105 lb/ft³ that is 4,200 lb, or 2.1 US tons. Dividing by 0.5 ft³ per bag gives exactly 80 bags. A 10% allowance changes the volume to 44 ft³ and the bag count to 88.
How the gravel calculator’s reference tables are calculated
The reference tables on the gravel calculator use the same calculation functions as the interactive tool, with 105 lb/ft³, no extra allowance and no compaction. The yard table starts from known cubic yards. Coverage per US ton is the reciprocal of the calculated tons needed for one square foot at the selected depth. The area table calculates each area and depth, then rounds the 0.5 ft³ bag count up. Tables are static examples and do not respond to changes in the calculator.
How calculations are checked
Automated checks cover known rectangle and circle examples, multiple areas, known volume, whole-bag rounding, invalid inputs and US-to-metric conversion invariants. Browser checks cover completed calculations, sharing and mobile use. Tests also fail if a recorded weight or price has no source link, or a weight has no recorded date.
These are software checks. They are not an independent engineering review, a check of your site conditions or verification of your supplier’s material.
To report a discrepancy, include the dimensions, units, bulk density, allowance and expected result. You can copy these from the order summary. Send a calculation correction, or use the contact page.
Changes and corrections
A correction fixes something that was wrong; an update adds or replaces material that was not in error. Each is dated by when the change was made.
Corrections
- · #57 stone calculator: Size No. 57 is now described as AASHTO M43 grades it, from 1 inch down to No. 4 (4.75 mm). It had been described as 1/2 to 1 inch stone.
- · Crusher run calculator: Removed a #57 limestone weight that had been quoted as a crusher run weight.
- · Cubic yards to tons, Gravel weight per yard: The range of supplier weights no longer includes the 105 lb/ft³ general estimate, which is not a supplier’s figure.
Updates
- · Gravel calculator, Gravel driveway cost guide, Pea gravel bags vs. bulk, Dump truck loads: Replaced labelled hypothetical example prices with published supplier prices.
- · Dump truck loads: Expanded from “Gravel delivery minimum orders” into a guide to dump truck loads and retitled; the old address, /blog/gravel-delivery-minimum-order, redirects here.
- · Coverage per ton: Added 7 published coverage figures from 5 suppliers, with the weight per yard each implies.
Scope and limits
This tool estimates material quantities. It does not design structural layers, drainage or a driveway. Use separate estimates for different materials. Measure an irregular area as smaller shapes, avoid double counting overlap and check the final specification with your supplier or installer.
The same functions run every calculator on the site; each opens on its own material’s published weight. See them side by side in the material comparison.