# Roofing Squares Calculator: Square Feet to Bundles

Canonical URL: https://www.simplywise.com/blog/roofing-squares-and-bundles-calculator/
Plain text: https://www.simplywise.com/blog/roofing-squares-and-bundles-calculator/llms.txt
Publisher: SimplyWise, Inc. (https://www.simplywise.com)
Published: August 25, 2026
Updated: October 5, 2026
Category: How to Estimate
Summary: Convert roof square feet into roofing squares and bundles, with the pitch multiplier, published bundles per square by shingle type.

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## Roofing Squares Calculator: Square Feet to Bundles

Roofing squares are the easy part. The bundle count moves with the shingle you spec, and three per square is not a law.

At a glance

1. One roofing square covers 100 sq ft of roof, per TAMKO.
2. Footprint is not roof area. Multiply by the slope factor for the pitch.
3. Bundles per square run 3, 4, or 5 depending on the shingle.
4. A nominal square of laminate can cover 98.4 sq ft, not 100.
5. Starter and hip and ridge are their own linear foot lines.
6. Data sheets skip waste. IKO’s estimating guide works its sample job at a 10 percent waste allowance.

## Roofing squares start with slope, not footprint

A roofing square is 100 sq ft of roof surface. TAMKO states it on its own data sheet: one sales square covers 100 sq ft.

The trap is what you measure. A ground measurement or a plan gives you footprint, and a pitched roof is always larger. Multiply footprint by the slope factor for the pitch. That factor is the hypotenuse of a 12 in run and the rise, divided by that 12 in run, so a 6/12 comes out at 1.118.

| Pitch | Slope factor | 1,200 sq ft footprint | Squares |
| --- | --- | --- | --- |
| 4/12 | 1.054 | 1,265 sq ft | 12.65 |
| 5/12 | 1.083 | 1,300 sq ft | 13.00 |
| 6/12 | 1.118 | 1,342 sq ft | 13.42 |
| 8/12 | 1.202 | 1,442 sq ft | 14.42 |
| 9/12 | 1.250 | 1,500 sq ft | 15.00 |
| 12/12 | 1.414 | 1,697 sq ft | 16.97 |

Read the spread. The same 1,200 sq ft footprint is 12.65 squares on a 4/12 and 16.97 squares on a 12/12.

## Bundles per square is a product spec, not a constant

Three bundles per square is the strip and standard laminate answer. It is wrong the moment you spec a heavier shingle.

| Shingle | Class | Bundles per square | Published coverage |
| --- | --- | --- | --- |
| TAMKO Elite Glass-Seal | 3-tab strip | 3 | 100 sq ft |
| IKO Cambridge | Architectural | 3 | 100 sq ft |
| CertainTeed Landmark | Architectural | 3 | 98.4 sq ft |
| TAMKO Heritage | Architectural | 3 | 98.4 sq ft |
| IKO Crowne Slate | Designer | 4 | 100 sq ft |
| IKO Armourshake | Designer | 5 | 100 sq ft |

## Worked example: a 40 by 28 gable at 6/12

Footprint is 1,120 sq ft. At the 6/12 factor of 1.118 the roof surface is 1,252 sq ft, or 12.52 squares.

On IKO Cambridge at 3 bundles per square that is 37.56, so 38 bundles. Spec IKO Crowne Slate at 4 and the same roof takes 50.08, so 51 bundles. Spec IKO Armourshake at 5 and it is 62.6, so 63 bundles. Same roof, 25 more bundles to hump up a ladder.

## Watch the 98.4

Some laminates cover less than a true square. CertainTeed Landmark and TAMKO Heritage both publish 98.4 sq ft per square, not 100.

Run that 1,252 sq ft roof on Landmark and you need 1,252 divided by 98.4, which is 12.72. At 3 bundles that is 38.17, so 39 bundles. One bundle sounds like nothing until it is the bundle you drive back for.

## Skip the retyping

Once the count is settled, hand typing is the slowest part of the bid. SimplyWise Cost Estimator turns a photo into an itemized, branded estimate in about 6 seconds. Pricing is $29.99/mo or $239.99/yr, about $20/mo on annual, with a 7-day free trial.

## Starter, ridge, and underlayment are separate lines

These get counted in linear feet and rolls, not squares, and they are where a tight bid leaks.

On that gable, the two eaves run 80 linear ft. CertainTeed SwiftStart covers 116.25 lineal ft per bundle, so one bundle carries it. The 40 ft ridge on IKO Hip and Ridge 12, at 29.53 linear ft per bundle, takes 1.35 bundles, so order two.

Underlayment goes by roll and by lap. IKO StormTite is 1,000 sq ft per roll, so 1,252 sq ft takes two. TAMKO publishes the honest version on Synthetic Guard: the roll contains 1,001 sq ft but covers 905.67 sq ft, because the laps eat 9.5 percent.

## About waste

Here is what the spec sheets leave out. Across six shingle data sheets from three manufacturers, not one prints a waste percentage. IKO’s estimating guide works a sample job at a 10 percent waste allowance, and that is the only waste figure in any document cited here.

Treat waste as a judgment line you own, driven by valleys, hips, dormers, and cut-up planes. Put it on the quote as its own number rather than burying it in a square count a customer can check.

## Count roofing squares in this order

1. Measure planes, then apply the pitch factor Take each plane’s footprint, multiply by the slope factor, and add the planes together.
2. Pick the shingle before you count bundles Pull the bundles per square off that product’s data sheet. Three is an assumption, not a spec.
3. Check coverage per square If the sheet says 98.4, divide by 98.4. Do not divide by 100 and hope.
4. Count linear feet separately Eaves for starter, ridges and hips for cap, then rolls for underlayment against its covered area.

## Keep reading

- How to Estimate a Roofing Job (https://www.simplywise.com/blog/how-to-estimate-roofing-job/)
- Concrete Cubic Yard Calculator (https://www.simplywise.com/blog/concrete-cubic-yard-calculators/)
- Best Estimating Apps for Roofing Contractors (https://www.simplywise.com/blog/best-estimating-app-roofing-contractors/)
- Construction Calculators for Contractors (https://www.simplywise.com/blog/construction-calculators/)

## Sources

- TAMKO, Elite Glass-Seal data sheet (https://www.tamko.com/docs/default-source/data-sheets/TAMKO-3-tab-elite-glass-seal-data-sheet-(joplin).pdf?sfvrsn=a30256a0_29) (one sales square covers 100 sq. ft., 3 bundles; verified 2026-08-22).
- TAMKO, Heritage data sheet (https://www.tamko.com/docs/default-source/data-sheets/tamko-heritage-data-sheet-(joplin).pdf) (98.4 sq. ft. per sales square; verified 2026-08-22).
- IKO, Cambridge technical data sheet (https://www.iko.com/na/wp-content/uploads/2024/12/4220XXX_IKO_TDS_Cambridge_EN.pdf) (three bundles, 100 ft²; verified 2026-08-22).
- IKO, Crowne Slate technical data sheet (https://www.iko.com/na/document-library/iko-crowne-slate-technical-data-sheet-en.pdf) (four bundles, 100 ft²; verified 2026-08-22).
- IKO, Armourshake technical data sheet (https://iko.com/na/document-library/iko-armourshake-class3-shingles-technical-data-sheet-en.pdf) (five bundles, 100 ft²; verified 2026-08-22).
- CertainTeed, Landmark product data (https://www.buildsite.com/pdf/certainteed/Landmark-Shingles-Product-Data-2899919.pdf) (3 bundles, 98.4 sq ft per square; verified 2026-08-22).
- CertainTeed, SwiftStart data sheet (https://images.hancocklumber.com/SwiftStart_TDS_CTRCOMM-015_2103_E.pdf) (116-1/4 lin. ft per bundle; verified 2026-08-22).
- IKO, Hip and Ridge 12 data sheet (https://mediaresourcecenter.iko.com/m/f4327ffc8d8f7ba5/original/IKO_TDS_HR12_HRC4_EN.pdf) (29.53 linear ft per bundle; verified 2026-08-22).
- IKO, Estimating How Much Roofing Is Required (https://www.iko.com/na/wp-content/uploads/sites/8/document-library/Estimating-How-Much-Roofing-Is-Required.pdf) (assume a 10% waste allowance; verified 2026-08-25).
- IKO, StormTite underlayment data sheet (https://www.iko.com/na/document-library/iko-stormtite-technical-data-sheet-en.pdf) (1,000 ft² per roll; verified 2026-08-22).
- TAMKO, Synthetic Guard data sheet (https://www.tamko.com/docs/default-source/data-sheets/TAMKO-synthetic-guard-data-sheet.pdf) (contains 1,001 sq. ft., covers 905.67 sq. ft.; verified 2026-08-22).
- SimplyWise Cost Estimator, App Store (https://apps.apple.com/us/app/simplywise-cost-estimator/id6670619664) (4.8 rating; verified 2026-08-22).

## Common questions from roofers about roofing squares

**How many square feet is a roofing square?**

One hundred. TAMKO states on its data sheet that one sales square covers 100 sq. ft. of roof surface.

**How many bundles are in a roofing square?**

Three for strip and standard laminate shingles, four for IKO Crowne Slate, five for IKO Armourshake. Read the data sheet for the product you specced.

**Why does my shingle say 98.4 square feet?**

Some laminates cover slightly under a true square. CertainTeed Landmark and TAMKO Heritage both publish 98.4 sq ft per square, so divide roof area by 98.4.

**How do I convert roof footprint to roof area?**

Multiply by the slope factor for the pitch. A 6/12 is 1.118 and a 12/12 is 1.414, so on a 1,200 sq ft footprint pitch alone swings the count from 13.42 squares to 16.97.

**What waste factor should I add to a shingle order?**

No data sheet prints one. IKO’s estimating guide works its sample job at a 10 percent waste allowance. Set your number off valleys, hips, and dormers, and show it as its own line.

**Can SimplyWise price a roof from a photo?**

Yes. SimplyWise Cost Estimator turns a photo into an itemized estimate in about 6 seconds. Free to try, at $29.99/mo or $239.99/yr.

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