RoofTally: free roofing calculators, sources on every figure
Roof area, shingles or tiles, battens and underlayment, from manufacturer coverage figures.
Three calculators for homeowners and small contractors: roof area, squares and bundles of shingles with underlayment, ridge cap, nails and drip edge; the pitch in x:12, degrees and the area multiplier; UK roof tiles per m² with battens and ridge tiles. No account, no address form, nothing stored on our servers.
The calculators
Roof shingle calculator
Roof area from the footprint and pitch, squares, bundles at 3 per square, underlayment rolls, ridge cap, nails and drip edge, with a cost range by material.
Roof pitch calculator
Rise, run, degrees or x:12 into each other, with the area multiplier and a table of common pitches.
Roof tile calculator (UK)
Tiles per m² from Marley and Redland data sheets, battens from the gauge, ridge tiles, and the cost from your price per tile.
Quick answers
The figures people ask for most, computed by the same code as the calculators, each with the page that shows the working and the sources.
| Question | Answer | Worked out in |
|---|---|---|
| Bundles of shingles per square | 3 for standard shingles (Owens Corning 2013, IKO 2023) | Bundles per square chart |
| Roof tiles per m² (UK) | 9.7 to 60 by tile type (manufacturer and merchant figures) | Tiles per m² by type |
| Roof pitch 6:12 in degrees | 26.6°, the plan x 1.118 | Roof pitch chart |
| Roof area of a 12 x 9 m plan at 35° | 131.8 m² (plan x 1.221) | Roof area in m² |
| Roof tiles supplied and fitted, per m² (UK) | £80 to £150 concrete, £120 to £230 clay, £150 to £300 slate (MyJobQuote 2026) | UK roof tile prices |
| New roof, 1,500 sq ft footprint (US) | $6,708 to $10,062 in architectural shingles at 6:12, installed (HomeAdvisor 2026) | 1,500 sq ft roof cost |
| Waste to add | 10% on a simple gable, 15% with hips and valleys (IKO) | How to measure a roof |
Every guide, grouped by calculator: all roofing guides.
How it works
- Type each roof section as a rectangle on the plan: length along the ridge, width from eave to eave, the overhang past the walls, the pitch (x:12 or degrees) and whether it is a simple gable or a hip. An L-shaped house is two sections; a garage or a dormer is another.
- Pick the product: 3-tab or architectural shingles with the underlayment and ridge cap, or a UK tile type. Every coverage figure starts from the manufacturer data sheet and shows its source and the date it was read under the field; change any of them.
- Read the quantities rounded up to what you buy: bundles, rolls, ridge cap bundles, pounds of nails, drip edge pieces, or tiles, metres of batten and ridge tiles, and a cost range from a published cost guide with its year. The sections stay in your browser, so the tile calculator and the Pro list see the same roof.
Units follow the region you pick: US (ft, sq ft, squares, $) or UK / metric (m, m², £). The maths is the same everywhere: roof area = footprint x the pitch multiplier; the units, the currency and the cost presets change.
Where the figures come from
Bundles per square from the Owens Corning specification guide (Owens Corning, Section 07 31 13 specification guide, 2013, TruDefinition Oakridge shingles, read 2026-09-20) and IKO (IKO, "How Many Square Feet in a Bundle of Shingles", 19 July 2023, read 2026-09-20); waste from IKO’s measuring guide; roll coverage from Owens Corning and Atlas; ridge cap from a GAF listing and the IKO data sheet; tiles per m² from the Marley product pages (Marley, Modern interlocking concrete roof tile, technical specification, read 2026-09-20) and the BMI Redland pages; cost ranges from HomeAdvisor (US, 2026) and MyJobQuote (UK, 2026). Each calculator lists its sources with the date they were read, and every figure is yours to change.
Planning quantities from manufacturer coverage figures and published cost ranges, each with its source and date: measure the roof and follow the product data sheet. Not a structural assessment.
Frequently asked questions
- What is RoofTally?
- RoofTally is a set of three free roofing calculators, for roof shingles, roof pitch and UK roof tiles, with guides that work the common cases out in tables. Every coverage figure and cost range comes from a manufacturer data sheet or a published cost guide with the date it was read, and the sums run in your browser.
- Are the calculators free?
- Yes, all three, with no limit, no sign-up and no address to type. Pro is a paid extra for people ordering for a whole roof who want the materials list and the estimate on one printable sheet with an Excel export; the free tools do not change.
- How accurate is a roof area from the footprint?
- For a roof where every slope has the same pitch, footprint x multiplier is exact, gable or hip. Dormers, different pitches on wings and valleys between sections are what the sections list is for: add each part as its own rectangle with its own pitch. The result is a planning quantity; the roofer measures before ordering.
- Do you sell leads or pass my details to roofers?
- No. There is no address form and no quote request; the numbers you type stay in your browser. The only thing that leaves your device is the email you type at Stripe if you buy Pro.
- What does Pro add?
- One sheet for the whole roof: every section with its area, the totals in squares and bundles or tiles and battens, underlayment, ridge, nails, drip edge, waste and the cost range by material with its source and year. Printed or saved as PDF from the browser, or exported to Excel with the sources on their own sheet.