Measure the area
Length × width of the path or gravel bed.
Gravel Calculator
Measure your path or gravel garden area, choose depth, and get m³ and tonne estimates before you order.
Calculator
Tap a screen and type with the keypad (or your keyboard), choose an option, then press =. The answer shows on the calculator screen, with full details underneath.
Garden Plant Finder
GRAVEL · GPF
How to measure
Follow these steps for accurate inputs and better results.
Choose depth
3–5 cm suits many decorative paths over a firm base.
Prepare the base
Level, compact, and consider membrane for weed control.
Edge the area
Edging stops gravel migrating into lawns and borders.
Why this matters
Gravel is sold by volume or tonne — guessing leads to half-finished paths or costly leftovers.
Correct depth looks neat, stays put better, and suppresses weeds more effectively.
Weight matters for delivery and for weak surfaces such as roofs or balconies.
Common mistakes
No edging
Gravel spreads into lawns and becomes a mowing hazard.
Too shallow
Bare patches appear quickly on busy paths.
Skipping the base
Soft ground means ruts and constant topping up.
Wrong grade for the job
Fine grit and chunky aggregate behave differently underfoot.
Blocking drainage
Don’t seal areas that need to shed water — plan falls carefully.
Tips from gardening experts
Order a little extra
Uneven ground and settlement use more than flat maths suggests.
Rake level
Finish with a landscape rake for an even face.
Plant for gravel gardens
Mediterranean herbs love sharp drainage and reflective heat.
Keep soil separate
Soil contamination grows weeds in gravel fast.
Frequently asked questions
How much gravel do I need?
Area (m²) × depth (m) = m³. Example: 5 m² at 4 cm = 0.2 m³.
How many tonnes per m³ of gravel?
Often around 1.5–1.7 t/m³. We estimate ~1.6 t/m³ for planning.
What depth for a garden path?
About 3–5 cm of decorative gravel over a prepared base is common for light foot traffic.
Do I need weed membrane?
Helpful on paths. In planted gravel gardens, membrane can hinder planting — use selectively.
Self-binding gravel vs loose gravel?
Self-binding firms into a path surface; loose gravel stays decorative and shifts more.
Can I put gravel over soil?
Yes with preparation. Remove weeds, level, and consider a base layer for busy routes.
Is gravel good for drainage?
Around plants, grit improves surface drainage; thick gravel mulches still need thoughtful planting choices.
How do I stop cats using gravel beds?
Dense planting, prickly mulches, or motion deterrents help more than depth alone.
What size gravel is best?
10–20 mm is a popular decorative grade for paths; check local supplier advice.
Can this calculator size a driveway?
No — driveways need engineered sub-bases. Use this tool for garden paths and decorative areas.
Sources and further reading
Want more detail? These pages from the Royal Horticultural Society (RHS), the UK’s gardening charity, explain the topic in depth.
Related guides
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Downloads
Gravel path checklist
Base, edge, depth and finishing.
Gravel grades PDF
Placeholder buyer’s guide.
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