What calculator to bring to the NASCLA exam

A good share of the NASCLA Commercial General Building exam is arithmetic: markup and margin, retainage, quantities, float and payroll. You bring your own calculator, and PSI's rules on which ones are allowed are short. This page explains them and how to practice.

The rules, from the bulletin

PSI's Candidate Information Bulletin (updated 7 Jul 2026) says only non-programmable calculators are allowed, and they must be:

• Silent.
• Battery-operated.
• Without paper tape printing. The reference section says "nonprinting".
• Without a keyboard containing the alphabet.

Everything else electronic goes in storage before you enter the room: phones, smart watches, tablets and the rest. A phone calculator is not an option. The bulletin does not mention an on-screen calculator, so plan to bring your own.

What fits those rules

A basic four-function calculator with a percent key, or a simple scientific calculator, fits the description as long as it is non-programmable, silent and has no letter keys. Things that do not fit:

• Graphing and programmable calculators.
• Anything with letter keys, whatever kind of calculator it is.
• Printing calculators with paper tape.
• Anything that beeps on each key press, unless the sound can be switched off.

Solar power. The bulletin says battery-operated. A dual-power model, with a battery as well as a solar cell, fits that wording. If yours is solar only, ask PSI before test day.

We do not name models. Check yours against the four rules above, and if you are in any doubt, ask PSI when you book rather than at check-in.

What it needs to do

You will not need anything advanced. The arithmetic on this exam is multiplication, division, percentages and the odd square root. A calculator with:

• large keys and a clear display,
• a memory key (M+, MR) for running totals,
• a square root key,

covers it. More functions mean more ways to press the wrong key.

Keystrokes to practice

Practice each until you can do it without thinking, then check with the second method. All numbers are invented.

Markup on cost. Cost $250,000 with a 12% markup: 250,000 x 1.12 = 280,000. Second way: 250,000 x 0.12 = 30,000, then 250,000 + 30,000 = 280,000.

Price for a margin. Cost $250,000 at a 12% margin: 250,000 / 0.88 = 284,090.91. Check: 284,090.91 x 0.88 = 250,000.00.

Cubic yards. A 60 ft by 40 ft slab, 6 in. thick: 60 x 40 x 0.5 = 1,200 cubic feet, then 1,200 / 27 = 44.44 cubic yards. Check: 44.44 x 27 = 1,200 (to rounding).

Running total in memory. Three pay items of $12,400, $8,750 and $3,125: press each then M+, and MR shows 24,275. Check by adding in pairs: 12,400 + 8,750 = 21,150, and 21,150 + 3,125 = 24,275.

The percent key varies. On some calculators, 250,000 + 12% gives 280,000; on others it does something different. Know what yours does, or skip the key and multiply by 1.12.

Test-day habits

• Put in fresh batteries the week before, and test every key the day before.
• Clear memory before each calculation chain.
• Keep the calculator free of stickers and writing, so there is nothing to question at check-in.
• Work each money answer twice, once each way, when you have time on the second pass.

More on exam timing: how to pace 125 questions in 330 minutes. For what else to bring and when to arrive, see cost, scheduling and retakes.

Take the free 10-question check with the calculator you plan to bring, and see your score by subject area in minutes. It needs no signup and explains every answer.

The NASCLA Commercial course has a lesson for each of the 12 subject areas that shows which listed reference to open and how to apply it, original practice questions with every answer worked, and four timed practice exams of 115 questions on a 330-minute clock. Your scores come back by subject area, so you know where the next study hour goes. See the course.

Not affiliated with or endorsed by NASCLA or PSI. NASCLA and PSI are named only to identify the exam and its test vendor.

FAQ

Can I use a calculator on the NASCLA exam?

Yes, your own. It must be silent, nonprinting, non-programmable and battery-operated, with no alphabetic keyboard.

Is there an on-screen calculator on the NASCLA exam?

PSI's bulletin lists the calculator you may bring and does not mention an on-screen one, so bring your own.

What math is on the NASCLA exam?

Business and estimating arithmetic: markup and margin, retainage, quantities, float and payroll, among others. Practice it on the calculator you will bring.

Sources

Show the list

• PSI Candidate Information Bulletin 1458, security procedures and reference list sections, updated 7 Jul 2026. Retrieved 5 Nov 2026.