How do I calculate how much gravel I need?

Volume (m³) = Length (m) × Width (m) × Depth (m) Weight (tonnes) = Volume × Density (kg/m³) / 1,000 Example — 5m × 4m area, 75mm depth, crushed stone (1,600 kg/m³): • Volume = 5 × 4 × 0.075 = 1.5 m³ • Weight = 1.5 × 1,600 / 1,000 = 2.4 tonnes • Bulk bags (1t): 3 bags • 25 kg small bags: 96 bags Note: gravel suppliers often list coverage as 'm² per tonne at Xmm depth'. This calculator works from area + depth so you always get the exact weight for your specific dimensions and chosen gravel type.

How deep should I lay gravel?

Recommended depths by application: • Decorative scatter / pot topping: 25–40mm (1–1.5") • Garden paths, borders, flower beds: 50mm (2") • Lightly used paths: 50–75mm (2–3") • Residential driveways (cars): 75–100mm (3–4") — lay in two layers: 50mm compacted base + 25–50mm top • Heavy driveways / parking: 100–150mm (4–6") • Sub-base under concrete / slabs: 100–150mm MOT Type 1 compacted • Drainage systems / soakaways: 200–300mm+ For driveways, always use angular crushed stone or MOT Type 1 for the base layer (it locks together under pressure). Rounded pea gravel rolls away under vehicle tyres.

How much does a tonne of gravel cover?

Coverage per tonne depends on gravel type and depth: For crushed stone (1,600 kg/m³): • At 25mm: 25.0 m² per tonne • At 50mm: 12.5 m² per tonne • At 75mm: 8.3 m² per tonne • At 100mm: 6.25 m² per tonne • At 150mm: 4.17 m² per tonne For pea gravel (1,520 kg/m³, slightly lighter): • At 50mm: 13.2 m² per tonne • At 75mm: 8.8 m² per tonne • At 100mm: 6.6 m² per tonne Rule of thumb: 1 tonne of standard gravel covers approximately 10–14 m² at 50mm depth.

Should I order loose delivery or bulk bags?

Comparison: • Loose tipper delivery: cheapest per tonne, minimum order typically 5–10 tonnes, needs large delivery vehicle access, material dumped in driveway/garden — you spread it yourself. • 1-tonne bulk bags (jumbo bags / IBC bags): flexible — can order 1 or more, delivered by crane/hiab truck, can be placed precisely. Slightly more expensive than loose but more practical for smaller quantities. • 25 kg small bags: most expensive per kg but convenient for small jobs and tight access. Never use small bags for jobs over ~2 m³ — the cost premium becomes very significant. Break-even guide: if you need more than 1–2 m³, bulk bags or loose delivery are nearly always cheaper. The calculator shows both cost options side-by-side so you can compare.

What type of gravel is best for a driveway?

For driveways: • Best base layer: MOT Type 1 / Crushed Limestone — angular, self-compacting, doesn't shift under load. Always compact in layers. • Best top layer: 20mm crushed stone or angular gravel — grips tyres, doesn't scatter as badly as pea gravel. • Avoid for driveways: round pea gravel and river rock — they roll under tyres, accumulate in the road, and are a tripping hazard. • Alternative: resin-bound gravel on a solid base — the gravel is locked in resin, giving a firm surface with drainage. Much more expensive but maintenance-free. For a standard residential driveway: lay 100–150mm of compacted MOT Type 1 sub-base first, then 25–50mm of washed decorative gravel on top.

What is the difference between pea gravel, crushed stone, and MOT Type 1?

Pea gravel: • Small, rounded, 6–10mm • Smooth to walk on, decorative • NOT suitable for driveways (rolls away) • Good for: garden paths, borders, drainage, decorative beds Crushed stone / angular gravel: • Angular, sharp edges, 10–40mm • Locks together under compaction • Good for driveways and base layers • Good for: driveways, hardstanding, general fill MOT Type 1 (Granular Sub-Base): • Crushed limestone or granite, graded 0–40mm • Compacts to a very firm base • Engineering specification material • Good for: road sub-base, driveway base, patio/slab sub-base River rock / cobbles: • Rounded, larger (20–100mm) • Decorative only — not load-bearing • Good for: water features, Japanese gardens, erosion control Slate chippings: • Flat, angular, purple-blue colour • Decorative, lighter than stone • Good for: borders, between stepping stones, low-use paths

Gravel Calculator — Tonnes, Bags & Cost

The Gravel Calculator tells you exactly how many tonnes of gravel to order for any area. Enter your length and width in metres or feet, set your depth in millimetres or inches, choose from six gravel types — pea gravel, crushed stone, river rock, limestone, slate chippings, or sharp sand — and the calculator instantly ..

GRAVEL DETAILS

GRAVEL TYPE

Crushed Stone: 1600 kg/m³

LENGTH (m)

WIDTH (m)

DEPTH (mm)

SMALL BAG SIZE

PRICE PER TONNE (optional)

PRICE PER 25 KG BAG (optional)

Tip: bulk bags or loose delivery is almost always cheaper than small bags for large areas.

RESULTS — Crushed Stone

WEIGHT NEEDED

1.600 t

= 1,600 kg

VOLUME

1.000 m³

1.308 yd³

BULK BAGS (1t)

1-tonne bags

SMALL BAGS (25 kg)

64 bags

CROSS-SECTION VIEW — Crushed Stone · 50mm depth

GRAVEL SUMMARY

Area20.00 m²

Depth50 mm

Volume1.000 m³ (1.308 yd³)

Weight1.600 tonnes (1,600 kg)

Bulk bags (1t)2 bags

25 kg bags64 bags

DEPTH GUIDE

25–40mm1–1.5"Decorative scatter, pot topping

50mm2"Paths, borders, light foot traffic

75mm3"Driveways, heavier use

100mm4"Heavy driveway, weed suppression

150mm6"Sub-base layer under slabs

200mm+8"+Deep fill, drainage systems

GRAVEL TYPES — DENSITY REFERENCE

Pea Gravel

1520 kg/m³

Crushed Stone

1600 kg/m³

River Rock

1540 kg/m³

Limestone / MOT Type 1

1680 kg/m³

Slate Chippings

1350 kg/m³

Sharp Sand / Grit

1700 kg/m³

Created with❤️byeaglecalculator.com

HOW TO USE

1
Select your gravel type. Each type has a different density which affects the weight calculation: pea gravel and river rock are lighter (~1,520–1,540 kg/m³), crushed stone and limestone are heavier (~1,600–1,680 kg/m³), and sharp sand is the heaviest at ~1,700 kg/m³. The colour dot next to each type matches the cross-section visualiser on the right.
2
Enter the area dimensions — length and width in metres or feet. For irregular shapes, break the area into rectangles, calculate each separately, and add the results. For circular areas (e.g. a garden feature), use π × radius² for the area and enter that total into the length field with width set to 1.
3
Set your depth using the preset buttons: 25–50mm for decorative scatter and borders, 50–75mm for paths and light driveways, 100mm for heavy driveways, 150mm+ for sub-base layers under slabs or pavers. The cross-section diagram updates to show the gravel layer thickness.
4
Choose your preferred bag size (25 kg metric or 50 lb US) and optionally enter a price per tonne and/or price per small bag to get a cost comparison. For any significant project, bulk delivery by the tonne is considerably cheaper per kg than small bags.
5
Read your results: volume in m³ and yd³, total weight in tonnes and kg, number of 1-tonne bulk bags, number of small bags, and cost estimates for both bulk and bagged options side by side.

WORKED EXAMPLE

Gravel for a 5m × 4m garden path, 75mm deep, using pea gravel: Step 1: Volume Area = 5 × 4 = 20 m² Depth = 75mm = 0.075 m Volume = 20 × 0.075 = 1.5 m³ Step 2: Weight (pea gravel density = 1,520 kg/m³) Weight = 1.5 × 1,520 = 2,280 kg = 2.28 tonnes Step 3: Bulk bags needed ceil(2.28) = 3 bulk bags (1 tonne each) Step 4: Small bags as alternative 25 kg bags: ceil(2,280 / 25) = 92 bags Cost comparison at $65/tonne bulk vs $6/25kg bag: • Bulk: 2.28t × $65 = $148.20 • Small bags: 92 × $6 = $552.00 • Bulk delivery saves: $403.80 — order in bulk! Step 5: Volume in cubic yards 1.5 × 1.308 = 1.96 yd³

FREQUENTLY ASKED QUESTIONS

RELATED CALCULATORS

Excavation Volume Calculator

Calculate instantly

MORE EXCAVATION CALCULATORS

Excavation Volume Calculator

Calculate instantly →

Was this calculator helpful?

Last updated: April 29, 2026 · Formula verified by EagleCalculator team · Eagle-eyed accuracy for every calculation.