Edging calculator
Estimate whole edging units from measured runs, usable unit length and a visible allowance for cuts and unusable offcuts.
20 LAUNCH TOOLS
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When to use it
Use after sketching every run that will receive the selected edging product and confirming its usable installed length. It estimates units only, not a foundation, restraint or retaining structure.
How it works
Base units = total edge ÷ usable unit length. Apply the entered allowance once, then round up to a whole unit using precision-safe exact-whole handling. Apply any supplier pack or pallet increment separately after checking the sale unit.
Worked example
Assume 18 m of measured edge, 0.9 m usable units and a 5% allowance. 18 ÷ 0.9 = 20 units; 20 × 1.05 = exactly 21, so the result is 21 units. If the supplier sells only in larger packs or pallets, round 21 up once to that confirmed ordering increment.
Measurement guidance
The combined measured length of the relevant runs in metres, the usable installed length of one selected unit in metres and one explicit allowance percentage for cuts and unusable offcuts.
Buying and specification checks
All entered runs use the same unit and orientation. Corners, curves, changes of level, transitions and end details may need special units or create short offcuts; reusable offcuts depend on the actual layout. The calculator does not design support, haunching, foundations or retaining work.
Map each run and confirm the selected edging system
A reliable unit count starts with a labelled layout and the actual product dimensions, not a guessed perimeter.
- Sketch every straight, curved and stepped run. Label starts, ends, corners, junctions and changes of level, then total only the lengths that will use this selected unit; calculate another product or orientation separately.
- Confirm the exact profile, orientation and usable installed length from the manufacturer or supplier. Check whether corners, radii, transitions and ends need dedicated units rather than cutting a standard piece.
- Dry-plan the layout around prominent corners and curves before choosing an allowance. Consider which offcuts can genuinely be reused, then enter one project allowance so it is not added again later.
- Check stock, colour or batch consistency, sale packs or pallets, delivery and handling. Follow the selected system's project-specific details for foundations, bedding, haunching and restraint; obtain suitable design advice where the edge also retains ground or carries structural demand.
Common mistakes
- Using area or the full perimeter instead of only the runs receiving this unit
- Ignoring special corners, curves, transitions and short unusable offcuts
- Adding waste twice before also rounding to a supplier pack or pallet
FREE TOOL AND PROJECT PACK
What the free calculator provides
The free tool converts measured runs and the selected unit length into whole edging units, with your visible allowance for cuts and unusable offcuts. It does not select an edging system or specify foundations, restraint or retaining work.
What the dedicated pack adds
The Patio Project Pack turns an edging quantity into a controlled patio plan without replacing product or site-specific design.
- Site, measurement, levels and system-choice checklists for recording runs, corners, access and ground constraints.
- A materials schedule that records edging length, units, corners, support details, allowances and supplier ordering units alongside the other patio layers.
- Quote, order, delivery, work and completion records for checking products, edge details, access, waste and handover.
19-page printable digital workbook (PDF). Immediate digital delivery with 90-day access; no subscription.
Practical FAQs
Should I include both sides and the ends of a path?
Include every run that will actually receive this selected edging unit. Count two sides if both are edged, and include an end only where the design uses edging there. Mark starts, ends and junctions separately because their details can differ.
How should I allow for corners and curves?
Plan them with the chosen system first. Some use purpose-made corner or radius units; others need cuts that leave short offcuts. Enter an allowance that reflects that layout rather than assuming every offcut can be reused.
What if the supplier sells in packs or pallets?
Use the calculator's whole-unit result, including its one allowance, then round up once to the supplier's confirmed sale increment. Do not add another waste percentage merely because an ordering increment is required.
Does the result specify the foundation or a retaining edge?
No. It counts units only. Foundations, bedding, haunching, lateral restraint and any retaining function depend on the product, ground, loading and system details; follow the manufacturer and seek suitable design advice where needed.
Planning guidance, not a quotation or a substitute for project-specific design and competent advice.