Gravel Calculator
Estimate cubic yards of gravel based on area and depth.
Quick guide
- Measure length x width (or total area) in feet or meters.
- Use a realistic depth (many projects are 2-6 inches).
- Add a small buffer for compaction and uneven base.
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- If you’re building layers (base + top), estimate each layer separately.
- Pick the right product for the job (pea gravel, crushed stone, road base) because depth and density assumptions change.
- Confirm whether you’re planning installed (compacted) depth or loose delivered depth—mixing these is a common reason for shortages.
Depth and compaction matter
Gravel is planned by volume but often purchased by weight. Density varies by product type and moisture, so conversions differ between suppliers.
Depth is the biggest swing factor; confirm whether your depth is loose depth or compacted depth and add a buffer for uneven base.
If you're building a driveway or base layer, depth recommendations vary; use your local supplier's guidance for your specific aggregate and use case.
A common planning mistake is using one “depth” for the whole project. Many builds use multiple layers with different thickness targets and different materials.
Material choice is a performance choice. Round gravel can be comfortable underfoot, but crushed stone locks together better for driveways and high-traffic paths.
Base vs top layer notes: a compactable base (often crushed stone/road base) provides structure, while a top layer (pea gravel or decorative stone) is often about appearance and comfort. They are different products and usually different thickness targets, so estimate them separately.
If you mix products in one estimate, you can end up ordering the wrong type at the wrong depth (a common cause of ruts, migration, and rework).
If you have soft soil or recurring ruts, performance is usually about subgrade and drainage, not just adding more gravel. A geotextile separator and proper base thickness can matter more than extra surface stone.
Compaction happens in lifts. Trying to compact one very thick layer often leads to settling later, which shows up as potholes and low spots even if your initial estimate was correct.
Example workflow: estimate base rock and surface stone separately, order the base first, compact and grade, then re-measure before ordering the finish layer. That reduces over-ordering and helps you hit the final grade.
Edge containment changes how much gravel you keep. If the gravel has no edging, it will migrate into grass and walkways over time, which effectively increases the “maintenance volume” you’ll buy later even if the initial installation math was perfect.
Separator fabric is a stability tool. It doesn’t change the cubic yards you need on day one, but it can reduce how quickly gravel sinks into soft soil and helps your installed thickness stay closer to what you measured (project dependent).
Gravel Calculator
Estimate cubic yards of gravel based on area and depth.
Results
- Base volume (cubic yards)
- 2.78
- Waste buffer (cubic yards)
- 0.28
- Estimated cubic yards
- 3.06
How to measure your area
- For rectangles: area = length x width. For circles: area = pi x r^2.
- Break irregular shapes into rectangles, add them, and round up slightly.
- Convert depth to feet (in / 12) or meters (cm / 100).
- If the surface is uneven, take multiple depth checks and use an average instead of the single lowest spot.
- If you have multiple layers (base + top), measure/estimate each layer thickness separately and sum volumes at the end only if the materials are the same.
- If you’re filling ruts, measure them as smaller rectangles/trenches instead of applying one depth to the entire driveway.
Assumptions to double-check
- Depth is average depth after grading (low spots can increase volume).
- Material type affects density; supplier conversions (yards -> tons) vary.
- Compaction can reduce loose volume; buffers help avoid a second delivery.
- Drainage and edge containment affect long-term performance; volume math alone won’t fix a soft base or poor slope.
- If you plan to edge or contain the gravel (timbers, metal edging, curbs), it can change the true fill area and reduce long-term migration.
- If you’re placing gravel over soil, a separator fabric can reduce mixing and help maintain thickness over time.
Buying tips
- Confirm whether your supplier sells by yards, tons, or bags.
- Ask for a recommended depth for your application (driveway, path, base).
- Round up to delivery minimums and keep a small amount for touch-ups.
- If you’re building a driveway, ask about base stone vs surface stone; they’re often different products.
- Ask for the product name/gradation (e.g., #57 stone, crusher run, pea gravel) so you don’t accidentally order the wrong material.
- If you plan separator fabric or edging, budget those as separate materials; they don’t change volume but improve performance.
- Plan delivery placement so you can spread efficiently (dump location, access, protecting edges/landscaping).
- If you’re unsure about depth, order the base first; after compaction you can re-check grade and then order the finishing stone.
Common mistakes to avoid
- Using loose depth when you need compacted depth (or vice versa).
- Assuming one universal density for all gravel types.
- Forgetting base prep; soft subgrade can consume more material than expected.
- Ignoring drainage/slope and then chasing low spots with repeated top-ups.
- Using round stone as a driveway base where crushed stone is needed to lock together.
- Spreading a thick lift and skipping proper compaction, then dealing with settlement later.
Gravel depth planning (driveways and base)
Gravel is ordered by volume, but real results depend on compaction. Plan depth as “loose depth” vs “final compacted depth”.
| Use | Typical depth | Notes |
|---|---|---|
| Walkway base | 2–4 in | Often compacted |
| Driveway base layer | 4–8 in | Heavier loads ⇒ thicker base |
| Top layer / topping | 2–3 in | Separate from base layer math |
- Ask your supplier for density and yd³↔ton conversion for the exact product.
- Edge irregularities and compaction usually require a buffer.
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Results are estimates for informational purposes only. Always verify measurements and product specifications.