When I saw an ad for the DeWalt Mobile Pro construction-calculator app in the July JLC, I couldn’t resist scanning its embedded QR code with my iPod to check it out. That zipped me to the iTunes App Store, where I learned that the app is compatible with iOS devices and is copyrighted by DeWalt, Cengage Learning, and Infinity Softworks. Cengage Learning develops teaching, learning, and research solutions, while Infinity Softworks created the PowerOne line of calculator apps, which include spreadsheet-like templates geared to specific occupations.

After downloading and exploring a freebie that includes a calculator and several templates, I bought all eight currently available add-on packs, which cost 99 cents to $4.99 each or $19.99 for the complete Master Pack. The packs bundle templates dedicated to business, construction math, site work, concrete and masonry, carpentry, electrical, finish materials, and landscaping. The carpentry pack includes a trim-carpentry add-on that’s also sold separately. Most buyers would be far more selective, but I wanted to tour the complete package to get a feel for the interface and see if I could spot some obvious strengths and weaknesses. After spending hours tapping, flicking, and typing, I think the pros far outweigh the cons.


The more I use the free construction calculator, the more I like it. It includes three keypads that collectively offer standard math and trig functions, and it allows you to enter feet or inches with fractions or decimals (but not metric units). Users are also able to toggle between units in the view window. The precision is adjustable, and inches can be accurate down to 1/64. What’s more, you can calculate entire algebraic expressions by entering a single string of numbers and commands. Two types of storage are included: “History” displays a log of your entries and results, and “Memory” can store up to 10 numbers or equations, which can then be recalled to the calculator.

You also get nine free templates for calculating areas and volumes; converting between length, area, and volume units; and estimating slab concrete, drywall, paint, and studs. To use a template, you select it from a list, enter the required data, and view the results below. For help, you simply tap the “Overview” and “Examples” tabs up top. Each template automatically saves a history of your calculations, which you can view, name, annotate, delete, email, or recall to the template for further computation. You can also use the calculator while entering data into a template. On the iPhone and iPod Touch, calculated results can be entered directly into the templates.

I think the template format is great. Other virtual construction calculators I’ve seen mimic traditional ones, requiring you to use keystrokes in various combinations to enter data and view results. BuildCalc is one impressive competitor that includes templates, but they’re still tied to a keypad. The DeWalt Mobile Pro app isn’t limited by this constraint.


The trade-specific add-on packs dropped a mind-boggling 129 new templates into the app. Thankfully, the app makes it easy to find a template without scrolling through the entire list.

The business pack includes more than two dozen tools for small and large businesses, addressing everything from auto loans and leases to marketing ROI and bid for profit. The concrete and masonry pack also goes impressively deep, estimating everything from the concrete, rebar, and rebar chairs required for footings to the yards or bags of concrete required to fill post holes (factoring in the post voids). It even estimates the masonry materials you need to build a brick house.

The site-work and landscaping packs collectively address fence materials, cut/fill, soil-compaction loss, pavers, and more. One template allows you to estimate the height of a tree by plugging in your height, the length of your shadow, and the length of the tree’s shadow. The math add-on is mostly conversion templates that I will seldom use. The electrical pack is definitely geared toward pro electricians, but includes fundamental templates like Box Fill, Minimum Burial Depth, and Residential Service. The finish-materials pack costs a dollar, a low price for estimating tile, flooring, and countertops.

I have mixed feelings about the carpentry packs, though. On the one hand, you get detailed templates devoted to notching and drilling joists and studs and a stair template that factors in landings. On the other, some key templates are surprisingly lean. For instance, the template on baluster spacing calculates horizontal layouts but not stair-rail layouts. The baluster and stair templates are accurate to 1/16 inch. I wish they were accurate to at least 1/32 inch to avoid accumulated error (though you can easily adjust your actual layout where necessary). As for roof framing, you can calculate the lengths of regular hip and valley rafters, cripples, and ridge boards, but that’s it. Deck footings are calculated for covered decks only. I’m told that existing templates will be modified regularly as needed to improve their performance or keep them up to date, and that new templates and template packs are forthcoming. Once you buy a template pack, all of its upgrades are free.

The Bottom Line

I love the app’s free construction calculator. It’s versatile and convenient, and it includes trig functions that stair builders and roof framers will appreciate. I also like the easy-to-use templates. Because the calculator comes with free ones, you can take a test drive before buying any of the trade-specific add-on template packs. I see room for improvement, but this is a useful app that promises to evolve on the fly in response to customer feedback. An Android version is reportedly under discussion.