Best construction calculator app for iPhone (2026)

Search the App Store for a construction calculator and you get two very different kinds of app. Some are keypads for feet-inch-fraction arithmetic, the phone version of the handheld calculators carpenters clip to their belts. Others are takeoff apps: you type in the size of a roof, a deck or a room, and they tell you how many bundles, boards, sheets or bags to buy and roughly what the job will cost. Most people searching for a construction calculator app on an iPhone want the second kind. They're standing in a yard or on a ladder and need a material list, not a sum.

This guide covers what a good construction calculator app for iPhone should do. It then walks through the one we build, Roofing Calculator & Estimator, and is honest about where a different tool fits better.

What to look for in a construction calculator app

• It works offline. Basements, roofs and new builds often have no signal. If the app needs a connection to calculate, it will fail you at the worst moment.
• It gives quantities, not just areas. "805 sq ft" isn't a shopping list. "9 squares, 27 bundles, starter and ridge cap" is.
• It handles waste and pitch. A roof at 8/12 has about 20% more surface than its footprint, and cut-up roofs need extra for waste. An app that skips either will under-order.
• It covers more than one trade. Contractors and homeowners rarely do just one thing. The same weekend can involve a roof patch, a fence run and drywall in the garage.
• It saves and shares. Saved estimates, a material list and a PDF you can text to a customer or your supplier turn the numbers into something you can act on.
• It speaks your units. Feet or metres, ideally switchable, so you aren't converting by hand.

Roofing Calculator & Estimator: what it does on iPhone

Roofing Calculator & Estimator is our iPhone app, and the same app is called Smart Roofing Calculator on Google Play. It began as a roofing estimator and now has more than 140 calculators. All of them run on the phone with no login and no internet connection.

• Roof measurement: roof area from length, width and pitch (in sq ft, m² and squares), a roof pitch calculator and a camera pitch finder, and a pitch chart from 1/12 to 24/12.
• Roofing materials: shingles with waste, starter strip and ridge cap, plywood or OSB sheathing, underlayment, ice and water shield, drip edge, flashing, metal panels and screws, and flat-roof membranes (EPDM, TPO, modified bitumen).
• Framing and ventilation: truss count and cost, rafter length, gambrel, hip and shed roofs, and a ventilation planner using the 1/150 and 1/300 net-free-area rules.
• Costs: a full roof estimate and step-by-step project wizard, replacement and tear-off cost, labor hours, tear-off weight with dumpster size, and a repair-vs-replace advisor.
• Job tools: save estimates, export PDF quotes, and add items to a Job Cart material list. It works in feet or metres and in English or Spanish.

New in version 1.7: deck, fence, drywall and yard calculators

Version 1.7 added a Home & Yard Projects section, and it is live on the App Store now. On iPhone, this is where our non-roofing trade calculators live:

• Deck: a deck cost estimate (materials, labor, railing, stairs and permit, with a low–high range), boards, joists and screws, posts and footings, railing and baluster spacing, and stain.
• Fence: privacy, picket and vinyl fences, electric and deer fence, and a chain-link takeoff.
• Drywall: sheets, screws, mud, tape and corner bead for a room.
• Insulation: blown-in attic bags to a target R-value, and wall batts.
• Tile: boxes by pattern, grout, thinset and backer board.
• Lawn and gravel: sod pallets, topsoil, mulch and grass seed, and gravel in tons and truckloads.

Every one of these works in feet or metres and in English or Spanish, and each can be saved, sent to PDF or added to the Job Cart like the roofing tools.

A worked example: re-roofing a detached garage

Here's the math the app runs for you, done by hand so you can check it:

1. Footprint including overhangs: 24 ft × 30 ft = 720 sq ft.
2. Pitch 6/12 has a multiplier of about 1.118, so the roof surface is 720 × 1.118 ≈ 805 sq ft.
3. A roofing square is 100 sq ft, so that's 8.05 squares.
4. Add 10% waste for a simple gable: 8.05 × 1.10 ≈ 8.86, round up to 9 squares.
5. Architectural shingles usually come 3 bundles to the square, so 9 × 3 = 27 bundles, plus starter and ridge cap.

In the app, you enter the footprint and pitch once, and the shingle, underlayment, drip edge and nail counts follow from them. For the reasoning behind each step, read our roofing calculator guide.

When another kind of app fits better

Roofing Calculator & Estimator is a takeoff-and-estimate app. If what you need is a keypad for adding and dividing feet-inch-fraction dimensions, such as stair stringers, a dedicated dimensional calculator is built for that. If you run a crew and need scheduling, invoicing and customer records, a field-service suite will do more. Many contractors use both. They run the takeoff in a calculator and send the quote from another app. Our free Instant Quote Maker covers the quote side on iPhone and Android.

On Android? The trade calculators are separate apps

On Google Play, each trade also has its own free app: Smart Decking Calculator, Smart Fencing Calculator, Smart Drywall Calculator, Smart Insulation Calculator, Smart Tile Calculator, Smart Sod Calculator and Smart Gravel Calculator. Those single-trade apps are Android only. On an iPhone, you get the same trades inside Roofing Calculator & Estimator, so you don't need to search for separate iPhone versions. The Android Roofing app has the Home & Yard Projects section too, if you'd rather keep everything in one place.

Price

The app is free to download and use, with ads. A one-time in-app purchase (Pro) removes the ads. There is no subscription and no account. Pricing a specific deck? Our contractor estimate app guide works through a deck, a fence and a room of drywall on an iPhone, from tape measure to PDF quote.