Construction Master Pro alternatives

Construction Master Pro earned its reputation. Calculated Industries has been refining it since 1978, and its dimensional arithmetic is the reason the name is close to generic on a jobsite. This page is not an argument that it is bad.

It is for someone who has looked at the app's billing and decided they would rather not rent a calculator. Here is what exists instead, in the order we would actually suggest trying them.

1. Free browser calculators — usable today

The 12 calculators on this site do the calculations tradespeople reach for most, with no account, no trial and nothing uploaded. They run on your phone's browser, so there is nothing to install.

• Roof pitch & common rafter — Pitch to angle, slope factor, and common rafter length with the ridge deduction and tail.
• Hip & valley rafter — Hip length, hip angle, and the common difference that steps every jack rafter down.
• Stair stringer layout — Equal risers from a total rise, with tread depth, total run, stringer length and the 2R+T check.
• Board feet — Board feet from nominal dimensions, for one piece or a whole order.
• Concrete volume — Slabs, continuous footings and round piers in cubic yards, with waste and bag counts.
• Rebar mat & weight — Bar count both ways, total linear feet and weight, for a slab mat at your spacing.
• Wall framing takeoff — Studs, plates and sheathing for a straight wall — with what is deliberately left out.
• Roofing squares & bundles — Footprint and pitch to roof area, squares and bundles, with waste.
• Conduit offset bending — Multiplier, distance between bends, and the shrink to take off the measurement.
• Pipe rolling offset — True offset, travel and run when a pipe moves up and sideways at once.
• Compound miter for crown — Miter and bevel settings for sprung moulding cut flat, at any spring and corner angle.
• Drainage slope & fall — Total fall over a run, in inches per foot, percent or ratio — all three at once.

What they will not do: they are single-purpose calculators, not a general feet-inch-fraction keypad. If your day is mostly adding and subtracting dimensions like 14′ 7-3/8″ + 9′ 11-5/16″, the Construction Master's running arithmetic is still the better tool, and nothing here replaces it.

2. The physical Construction Master — paid once

Calculated Industries still sells the handheld calculators, as a one-time purchase. If what you actually value is the Construction Master itself rather than the app, this is the same maths with no subscription, and a battery that lasts longer than a phone's.

What it will not do: it is one more thing in the truck, and it will not sync or keep project notes.

3. A framing square — paid for decades ago

The rafter tables on a framing square give length per foot of run for common and hip rafters at every pitch. It is how this was done before calculators, and the numbers are exactly as right as they were.

What it will not do: anything quickly, or anything that is not rafters. Reading the tables accurately on a roof in poor light is where the errors come from.

4. A spreadsheet or any scientific calculator

The maths underneath all of this is standard trade geometry — slope factor from pitch, total rise divided into equal risers, board-foot volume, conduit multiplier and shrink — and most of it fits in a single spreadsheet cell. The construction glossary gives the formula for each term where there is one. Anyone comfortable with a spreadsheet can rebuild the ones they need, and then they are theirs permanently.

What it will not do: check itself. A mistyped formula is silently wrong forever. Ours are tested against fixtures with hand-derived answers; a spreadsheet you built at 6am is not.

5. Keld — not out yet

Keld is our app, in build for iOS and Android. Its everyday calculations will be free and its paid tier will be a single payment rather than a subscription — the price is not final yet.

It is not available to download, so it is not a real alternative today and we are not going to pretend otherwise. The browser calculators above are the same maths, and they are the part you can use now.

How to judge any other calculator app

There are other construction calculator apps, and we have not listed them because we have not verified their current pricing — and an alternatives page quoting a stale price is worse than no page. The questions that separate them:

• Is the paid tier a subscription or a single payment? Read the store's in-app purchase list, not the "free" badge on the download.
• Does it work offline? Basements, roofs and new builds have no signal.
• Does it show fractions to 1/16″? Decimal inches are not how a tape measure reads.
• Does it cover the functions you actually use? Count them. Most people use five or six.
• Does it show its formula? If you cannot check it, you are trusting it.

Common questions

Is there a free alternative to Construction Master Pro?

Yes, for the most common jobsite calculations. The 12 calculators on this site cover rafters, hips and valleys, stair stringers, board feet, concrete, rebar, wall framing, roofing squares, conduit offsets, rolling offsets, compound miter and drainage slope — free, with no account, in any browser. They do not replicate every function of Construction Master Pro, so check the ones you actually use.

How much does the Construction Master Pro app cost?

On the App Store the Construction Master Pro Calc app is a free download with a 14-day trial, then $4.99 a month or $39.99 a year for full access, as listed on September 28, 2026. Prices change, so confirm on the store listing.

Can I buy Construction Master Pro once instead of subscribing?

Calculated Industries sells physical Construction Master calculators as a one-time purchase. The app, as currently listed, is sold by subscription.

Does a framing square still work for rafter layout?

Yes. The rafter tables stamped on a framing square give length per foot of run for common and hip rafters at each pitch, and the geometry has not changed. It is slower than a calculator and depends on reading small print accurately, which is why most people moved away from it — not because it stopped being correct.

Check it against the job. Building codes, span tables and product specifications vary by jurisdiction and manufacturer. Your approved drawings and your local code govern, not this page.