Know when gravel thins. Predict refill visits, quantities, and costs. Compare scenarios for patios, paths, and driveways. Make smarter buying decisions year after year.
| Scenario | Area | Target depth | Loss rate | Threshold | Typical interval |
|---|---|---|---|---|---|
| Light foot traffic path | 120 ft² | 2.0 in | 10% | 80% | 18–24 months |
| Wheelbarrow garden run | 240 ft² | 2.5 in | 18% | 80% | 9–15 months |
| Driveway edge top-up | 500 ft² | 3.0 in | 22% | 85% | 6–12 months |
Use these as starting points, then tune loss and density to match your material and site conditions.
Gravel loss is usually highest where water and wheels concentrate. Slopes, driveway entries, and tight turns can shed 2–4 times more material than flat paths. Edging, drainage outlets, and traffic intensity are the biggest predictors of how quickly depth declines. Wind and leaf blowing can also move fines from decorative beds.
Take 8–12 depth readings and average them. For pedestrian paths, a finished depth around 2–3 inches (5–7.5 cm) is common, while light-drive surfaces often perform better near 3–4 inches (7.5–10 cm), depending on base strength and stone size. Record the date so you can track change over time.
If you have no history, start with 10–12% annual loss for low-traffic garden paths, 15–22% for wheelbarrow routes, and 20–30% for areas exposed to runoff or vehicle scuffing. Re-check after one season and adjust to match your site. Improving drainage and adding edging often cuts losses noticeably.
The threshold is the trigger point for a top-up. Many homeowners pick 75–85% of target depth: low enough to reduce delivery frequency, but high enough to avoid exposed base and weeds. Decorative beds may use a higher threshold for appearance. For drive edges, choose higher thresholds where rutting begins.
Placed gravel settles as voids close and fines migrate. A compaction allowance of 5–12% is a practical starting range, higher for rounded stone. Add a waste factor, often 3–10%, to cover spillage, edge feathering, and small grade corrections during raking. If you hand-spread from bags, waste can be lower.
Suppliers typically sell by weight. Typical bulk densities for dry gravel fall around 85–110 lb/ft³ (1,360–1,760 kg/m³), but moisture can raise delivered weight. Use your supplier’s data when available, then refine density using your invoice. Keeping density consistent improves repeat ordering accuracy.
Per-visit cost combines material, delivery, and labor. Delivery can dominate small jobs, so fewer larger top-ups may reduce total logistics costs. The calculator also reports an annualized cost, helping you compare a 6‑month plan versus a 12‑month plan. Use labor as a time value if you do the work yourself.
A multi-year schedule turns estimates into action. Apply an inflation rate to model future pricing and see the cumulative budget over your chosen horizon. Save the CSV to share with contractors and keep a simple maintenance log for better forecasts. After storms or snowplowing, update depth sooner than planned.
Start around 80% of your target depth. It balances appearance and stability while avoiding too-frequent deliveries. Raise it for decorative areas, and lower it slightly for low-visibility utility paths.
Use site category ranges: 10–12% for light foot traffic, 15–22% for wheelbarrow routes, and 20–30% for runoff or vehicle edges. Update the rate after a season using new depth readings.
Fresh gravel settles after placement. Compaction allowance increases the ordered depth so the surface reaches the finished target after rain, vibration, and normal traffic. Typical allowances are 5–12%, depending on stone shape and base firmness.
Order the way your supplier sells it. Many quote by weight, so density converts your needed volume into tons or tonnes. Use supplier density data when possible, then refine from your delivery ticket for best accuracy.
Improve drainage, add edging, and keep the surface crowned or slightly sloped. Prevent ruts and remove organic debris that traps moisture. These steps reduce migration and keep the base from pumping fines upward.
For most spreading jobs, 3–10% works well. Use higher values for irregular shapes, steep edges, or when you expect grading corrections. If you have precise edging and careful placement, you can reduce waste.
This calculator applies inflation to the full event cost, including delivery and labor. If you expect different growth rates, set inflation to a blended estimate that matches your local price trends over time.
Plan gravel upkeep early to keep paths looking fresh.
Important Note: All the Calculators listed in this site are for educational purpose only and we do not guarentee the accuracy of results. Please do consult with other sources as well.