Mortar and bedding calculator
Estimate bedding volume while keeping the selected paving system, bed depth, yield and ordering assumptions visible.
20 LAUNCH TOOLS
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When to use it
Use after the paving manufacturer or competent project specification has established a bedding system and an average bed thickness. This calculator estimates material volume; it does not choose a mortar, primer, mix or construction detail.
How it works
Base wet volume = area × bed thickness in metres × coverage factor. The allowance is then applied. The result stays in cubic metres and is not rounded to bags, mixer batches or delivery increments.
Worked example
Assume a measured 20 m² patio, a specified 30 mm average bed, coverage factor 1.0 and 10% allowance. Convert 30 mm to 0.030 m: 20 × 0.030 × 1.0 = 0.600 m³; 0.600 × 1.10 = 0.660 m³. Convert that wet-volume estimate into bags or separate ingredients only with the exact product yield or agreed mix schedule, then apply the supplier's sale increment once.
Measurement guidance
Net paved area in square metres, specified average bed thickness in millimetres, an optional coverage factor and a separate ordering allowance. Leave the coverage factor at 1.0 unless the selected system or supplier gives a justified multiplier.
Buying and specification checks
The calculation assumes an even average bed thickness across the measured area. The coverage factor is a multiplier, not a mix ratio or product yield. Product compatibility, mortar proportions, bonding primer, layer construction, weather limits and bag yield remain specific to the chosen paving and bedding system.
Confirm the bedding system before ordering
The volume estimate is only as useful as the measured area, specified average bed and product-specific yield behind it.
- Measure the net paved area and keep the sketch, dimensions and exclusions. Record the specified average bed thickness separately in millimetres; do not copy an excavation, sub-base or isolated low-point depth into the bedding field.
- Choose the paving and obtain its current installation instructions before fixing the bedding method. Manufacturer requirements can differ by material and product: for example, Marshalls requires its porcelain paving to be primed and installed on a full mortar bed. Do not carry that product rule across to every paving system.
- Check formation, sub-base, edge restraint, levels, drainage, access and storage before ordering. Confirm the selected bedding product or agreed mix, bonding treatment, working conditions, mixing equipment, safe handling and achievable batch size with the manufacturer or competent installer.
- Use the exact bag yield, component schedule or supplier conversion for the selected system to turn cubic metres into an order. Check minimum quantities and sale increments, and keep the calculator's allowance visible so it is not added twice.
Common mistakes
- Choosing a bed thickness or mix because it is the calculator default
- Treating wet volume as a universal bag count or dry-ingredient schedule
- Adding an allowance again after the calculator has already included it
FREE TOOL AND PROJECT PACK
What the free calculator provides
The free calculator converts a measured area, specified average bed thickness, explicit coverage factor and allowance into an estimated wet bedding volume. It does not choose the bedding system, specify a mix or convert volume into universal bag quantities.
What the dedicated pack adds
The Patio Project Pack helps plan and retain the wider patio project before ordering and through completion.
- Site, measurement, levels, water-route and complete paving-system checks.
- Materials, quantity, quote, order, access and delivery records.
- Preparation, laying, jointing, snagging, care and retained patio-passport controls.
19-page printable digital workbook (PDF). Immediate digital delivery with 90-day access; no subscription.
Practical FAQs
What does the coverage factor mean?
It is a simple editable volume multiplier. Leave it at 1.0 unless a product or project-specific source gives a reason to change it. It is not a mortar mix ratio, compaction factor or bag yield.
Does the result tell me how many bags of mortar to buy?
No. It is an estimated wet volume. Use the exact product's stated yield, or an agreed component schedule for a site mix, then round once to the supplier's actual sale unit.
Is 30 mm the right bed thickness for every patio?
No. It is only the calculator's editable starting value. The paving, substrate, loading, levels, bonding method and manufacturer or project specification determine the suitable system and thickness.
Does this calculator choose a suitable mortar mix or bedding system?
No. It estimates quantity from the inputs you provide. Compatibility, mix, primer, weather limits, construction and curing must follow the selected paving and bedding manufacturer's instructions or competent project advice.
Planning guidance, not a quotation or a substitute for project-specific design and competent advice.