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Gravel Depth Calculator

By Muhammad Abdullah Rauf · Founder, EverydayTools.proUpdated 2026-06-28

How deep should gravel be for a path or driveway?

Gravel volume is **area × depth**. For paths, pads, and driveway bases, measure footprint in feet and layer depth in inches.

**Imperial formula (rectangle):**

Cubic yards = Length (ft) × Width (ft) × Depth (in) ÷ **324**

**Example — 20×10 ft path, 3 in crushed stone:**

20 × 10 × 3 ÷ 324 = **1.85 cubic yards** (50 cu ft)

**Depth guide:**

**Coverage shortcut:** At 3 in depth, **1 cubic yard covers ~108 sq ft**.

**Metric formula:**

Volume (m³) = Area (m²) × Depth (cm) ÷ 100

Add **10–15% extra** for compaction and edge loss on driveways.

  • **2 in** — thin topping over existing base
  • **3 in** — standard foot path
  • **4 in** — driveway pad (compact in lifts)
  • **6 in** — heavy base under pavers

Gravel layer depth formula

The calculator treats the gravel zone as a flat rectangular prism or cylinder. An optional buffer increases order quantity for compaction and edge loss.

Formula

cu yd = L(ft) × W(ft) × D(in) ÷ 324  |  circle: π × r² × D(ft) ÷ 27  |  m³ = area(m²) × D(cm) ÷ 100

Assumptions

  • Gravel is spread evenly at the entered depth over prepared subgrade.
  • Volume is loose crushed stone before compaction.
  • Round pads are approximated as flat circles.

Limitations

  • Does not model variable-depth crowned driveways.
  • Structural road base may need engineering specs beyond this estimator.
  • Decorative river rock uses the Landscape Rock Calculator instead.

How to use Gravel Depth Calculator

  1. Pick a depth use case or path preset

    Tap Walkway (2 in), Foot path (3 in), Driveway (4 in), or Heavy base (6 in) — each sets recommended depth.

  2. Measure path or pad footprint

    Enter length × width for rectangular paths, total square footage, or diameter for round pads.

  3. Choose gravel depth

    Tap depth presets: 2 in topping, 3 in path, 4 in driveway, 6 in paver base under sand.

  4. Read cubic yards and bag count

    Bulk suppliers quote by the cubic yard. Enter bag size for retail bag count.

  5. Add compaction buffer

    Enable the order buffer for driveways and tamped bases — angular stone compacts 5–15%.

Gravel Depth Calculator examples

20×10 ft path at 3 in

Input

20 ft × 10 ft × 3 in

Output

50 cu ft · 1.85 cu yd

20 × 10 × 3 ÷ 324 = 1.85 cu yd.

10×40 ft walk at 3 in

Input

400 sq ft × 3 in

Output

100 cu ft · 3.70 cu yd

Long side-yard path — bulk delivery recommended.

12×20 ft drive pad at 4 in

Input

240 sq ft × 4 in

Output

80 cu ft · 2.96 cu yd

Compact in 2 in lifts.

30 m² at 7 cm (metric)

Input

30 m² × 7 cm

Output

2.1 m³ · 2,100 L

30 × 0.07 m depth = 2.1 cubic meters.

Who uses Gravel Depth Calculator?

Common real-world scenarios where this tool saves time.

Side yard foot path

20×10 ft path at 3 in: 200 × 3 ÷ 12 = 50 cu ft → ~1.85 cu yd. Compact angular #57 stone in 2 in lifts.

Driveway extension pad

12×20 ft pad at 4 in base: compact in two 2 in lifts with plate compactor before vehicle traffic.

Paver base gravel

10×10 ft patio at 6 in crushed base under 1 in sand screed — calculate sand separately.

Metric garden path

30 m² path at 7 cm: 30 × 0.07 = 2.1 m³. Useful for EU bulk bag orders.

Workflow guides

Step-by-step chains that connect related tools for common tasks.

Paver patio base stack

Gravel base then sand screed.

  1. Calculate 6 in crushed base.
  2. Calculate 1 in bedding sand. Sand Calculator
  3. Count pavers with buffer. Paver Calculator
  4. Compact gravel → screed sand → lay pavers.

Reference tables

Gravel depth by use

UseDepthNotes
Topping2 inOver existing compacted base
Foot path3 inStandard walk depth
Driveway pad4 inCompact in lifts
Paver base6 inUnder 1 in sand screed

Deeper structural layers need plate compaction between lifts.

Coverage — 1 cubic yard by depth

DepthSq ft per cu yd
2 in162
3 in108
4 in81
6 in54

Formula: 324 ÷ depth (inches) = sq ft per cubic yard.

Best practices

Install geotextile on soft soil

Slope paths for drainage

Order base and topping together

Common mistakes to avoid

Using pea gravel for structural base

Use **angular crushed stone** (#57 or similar) for paths and driveways — rounded pea gravel does not lock together.

Skipping compaction lifts

Compact gravel in **2–3 in lifts**. Dumping 6 in at once leaves soft spots.

Confusing depth guide with decorative rock

This tool guides **structural gravel layers**. Decorative river rock beds use the Landscape Rock Calculator.

Not adding buffer for driveways

Driveway pads compact 10–15% — enable the order buffer or short-order on delivery day.

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Frequently Asked Questions

How deep should gravel be for a walkway?

3 inches of angular crushed stone over compacted subgrade is standard for foot traffic. Use 2 in only as a thin topping over an existing base.

How much gravel for a 20×10 ft path at 3 in?

About 1.85 cubic yards (50 cu ft). Add 10% buffer for compaction → ~2 yards to order.

How deep should driveway gravel be?

4 inches compacted angular stone for light residential pads. Heavier traffic may need 6–8 in — consult a contractor for load requirements.

What gravel depth under pavers?

3–4 in compacted crushed base under pavers, then 1 in screeded sand. Use the Sand Calculator for the bedding layer.

Pea gravel vs crushed stone for paths?

Crushed angular stone locks together and compacts. Pea gravel shifts underfoot — better for decorative beds than structural paths.

How many bags of gravel in a cubic yard?

One cubic yard = 27 cu ft. At 0.5 cu ft bags: 54 bags. Bulk delivery is cheaper above ~2 cu yd.

Privacy, accuracy, and trust

Privacy

Path dimensions and depth values are processed only in your browser — EverydayTools does not collect or store your measurements.

Depth guides only — not civil engineering or driveway structural design. Confirm order quantities with your supplier.

Part of Calculator Tools

More free tools for the same workflow.

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Reviewed on 2026-06-28.