Roof Tile Calculator
Quickly work out tiles and weight. Shape picks a sensible waste %, you can change it anytime.
1) Roof Shape
2) Area & Units
3) Tile & Waste
Results
Roof Tile Calculator Guide (UK 2025)
The Roof Tile Calculator estimates how many tiles you need from roof area and tile size. It supports the five common roof shapes (gable, hip, pyramid, mansard and mono), works in m² or ft², and includes a waste allowance. Use presets like Marley Modern or enter your own tile dimensions.
How the Calculator Works
You can either enter a known roof area (m²/ft²) or let the tool multiply your length and width. Pick a tile preset or enter the tile’s cover size (length × width). The tool adds waste then divides by tile area to get the tile count.
Roof Shapes & Suggested Waste
| Shape | Typical Use | Suggested Waste | Notes |
|---|---|---|---|
| Gable | Most homes | ~10% | Simple; fewer cuts. |
| Hip | Detached homes | ~12% | More edge cuts at hips. |
| Pyramid | Square plans | ~14% | Cutting at all sides. |
| Mansard | Townhouses/lofts | ~15% | Steep lower + shallow upper runs. |
| Mono-pitch | Extensions, lean-tos | ~8% | Single slope, minimal cuts. |
These are starting points. Exposed sites, complex details or strong patterns can push waste higher.
Common Tile Types & Sizes
| Tile Type | Example Size | Notes |
|---|---|---|
| Concrete Interlocking | ≈ 420×330 mm | Fast to lay, consistent coverage. |
| Double Roman (Concrete) | ≈ 418×330 mm | Popular profile, similar coverage to interlocking. |
| Clay Pantile | Varies by brand | Curved profile; check maker’s coverage chart. |
| Plain Tile (Clay) | ≈ 265×165 mm | Small format; different rules due to headlap (use Slate/Plain guide). |
| Lightweight / Synthetic | Brand-specific | Lower weight per tile; always verify coverage. |
Example Calculations
| Example | Inputs | Method | Result |
|---|---|---|---|
| Gable roof with interlocking tiles | Length 10 m × Width 6 m; Waste 10%; Tile 420×330 mm | Plan = 60 m² → Total = 60 × 1.10 = 66 m² Tile area = 0.42 × 0.33 = 0.1386 m² |
≈ 476 tiles (66 ÷ 0.1386) |
| Hip roof, modern flat tile | Known area 95 m²; Waste 12%; Tile 300×335 mm | Total = 95 × 1.12 = 106.4 m² Tile area = 0.300 × 0.335 = 0.1005 m² |
≈ 1,059 tiles (round up) |
| Mono-pitch, US tile size | Area 40 m²; Waste 8%; Tile 16×10 in | Total = 40 × 1.08 = 43.2 m² Tile area = (0.4064 × 0.2540) = 0.1032 m² |
≈ 419 tiles |
Round up to full tiles and allow a few spare boxes for breakage and later repairs.
Tips for Ordering & Fitting
- Confirm tile cover size (net, not overall) from the data sheet.
- Use the right waste for your shape and site exposure.
- Order ridges/hips/verge as linear items (m) separately from field tiles.
- Follow the maker’s fixing schedule for nails/clips and wind uplift.
Affiliate Tools & Materials
- Roof Tiles – Travis Perkins
- Breather Membranes – Screwfix
- Roof Ladders & Safety – Amazon
- Stainless Roofing Nails/Clips – Amazon
Disclosure: Some links may be affiliate links that help support SmartBuildCalc at no extra cost to you.
Related Calculators
Frequently Asked Questions
What tile size should I enter?
Use the cover size (the area one tile actually covers on the roof), not just the overall size. Presets fill typical values you can tweak.
Why is my count different from the merchant’s take-off?
Merchants include product-specific details like gauges and fixings. This guide gives a close estimate; follow your supplier’s final take-off before ordering.
Do I need ridge and hip tiles in the total?
No. This total is for field tiles. Measure ridge and hip lines in metres and order matching fittings from the same range.
Can I just enter ft and inches?
Yes. Use ft/ft² for area and inches for tile size — the calculator converts everything.
Note: Always check the manufacturer’s data sheet for coverage, gauge, minimum pitch and fixing instructions before placing a final order.
