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Frequently Asked Questions

How to reset BuildCalc (iOS)

If BuildCalc launches OK but either some of the advanced functions do not work properly or you just want to reset to the factory settings, the following steps are recommended:

From the main keypad, tap:[Conv] [Prefs]
At the top of the “Preferences” screen, you should find the “Reset” cell. Tap either [Imperial] or [Metric] to reset BuildCalc to its factory settings.

However, if BuildCalc fails to launch or is frozen, you may wish to restart it.  You can do it by:

Return to your iOS devices home screen by pressing the home button.
Double tap the home button to show your currently running apps.

Find the BuildCalc icon in the row of currently running apps at the bottom of the screen.  There may be more than 4 apps running, so try swiping your finger from right to left on the botton row to show more running apps until you find BuildCalc.
Once you find the BuildCalc icon among the currently running apps, press and hold it until all of the icons at the bottom of the screen start to jiggle and show a red circle with a white minus sign.

Tap on the red circle with the minus sign for BuildCalc.  This will stop BuildCalc from running.
Tap your screen, above the bottom row, to hide the row of currently running apps.
Restart BuildCalc
If BuildCalc won’t start properly, try these …

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iOS5 crash

UPDATE: (10/28/11):  Version 2.1.6 is now available from iTunes.  v2.1.6 addresses all of the issues listed below.  Thank you for your patience during the approval process!

Entering values into the Advanced Function ([Stairs], [CmpMtr], [Balster], [Diag] and [Hip/V]) cause BuildCalc to crash on iOS5 updated devices. The fix has been found and will be submitted to Apple for review ASAP. Updates will be posted as they are available.

UPDATE (8AM EDT, 10/16/11): There are two issues with version 2.1.4

Old iPod touch: buttons missing from top row of buttons
iPhone2G: crash at launch (this may rather be an issue with 3.x versions of iOS).

A solution to the iPod issue has been found.  Currently, I am trying to replicate the iPhone2G issue.
UPDATE (5PM EDT, 10/15/11): Apple comes through! I am guessing that Apple anticipated a rash of issues with apps on iOS5 because their review of BuildCalc version 2.1.4 was in near record time! It is now available as a free update from the App Store. You can find upgrade instructions here.

UPDATE (2PM EDT, 10/13/11): First, my apologies for any trouble iOS5 may be causing you. Now that I have had a chance to get my hands on it, I like what I see but it appears that a lot of apps (including BuildCalc) were not ready for the transition. Because of this, I won’t be updating iOS on my iPhone for a few weeks (until more apps are updated).

As for BuildCalc, a new binary has been submitted to Apple for review. It has …

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How to move BuildCalc to your Android’s SD Card

Find and launch your Android device’s Settings app
Tap on the “Applications” cell
Tap on the “Manage Applications” cell
Tap on the “BuildCalc” cell (you may have to scroll to find it)
If enabled (not grayed out), tap on the [Force stop] button and then tap the [OK] button when you are asked if you are sure. If the [Force stop] button is grayed out, go to the next step.  
Tap on the [Move to SD card] button. The button will dim and show [Moving]  
When complete, the button should now read [Move to phone].

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Won’t launch, crashes, or freezes:

The following is a list of causes and recommendations if you find yourself having problems with BuildCalc.

Most likely (Apple): Your copy of BuildCalc did not download correctly when you purchased or updated it. The remedy is to uninstall and reinstall BuildCalc (preferably via iTunes rather than the App Store App). You can find instructions on how to do this here.
Most likely (Android): BuildCalc’s configuration files have become corrupted. The remedy is to clear BuildCalc’s data. Instructions are here.
If BuildCalc freezes when only using a particular function (but not the other functions), then the function’s configuration file may have been corrupted. There have yet to be any reports of this on Apple devices but this has happened on Android devices. The remedy is to re-instate BuildCalc’s factory settings by (within BuildCalc):

Tap [Conv] [Prefs]
Tap the [Imperial] or [Metric] button (depending one your preference) in the “Reset” cell.
Tap [OK] on the reset notification
Try the problem function again. If it still doesn’t work, try follow these instructions

You may have found a serious bug with BuildCalc. Unfortunately no software of any substance is bug free (and if it were, you’d be too busy dealing with the flying pig problem to notice). But if uninstalling and reinstalling doesn’t work, then please contact me as soon as possible so I can get you up and going right away.

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I uninstalled BuildCalc … how do I get it back?

Fortunately, both Apple and Android thought this one through for us.  The only thing you will need to know is the Apple iTunes or Google account you used to initialize your device.  Here are the instructions to get your copy of BuildCalc back.
Android Devices

Launch the Google Play (was Android Market) App and then tap on the search icon.
Enter “BuildCalc” into the search box and tap the [Go] button.
Notice the “Purchased” text at the bottom right of the BuildCalc cell. This indicates that Google remembered your purchase and that you can redownload BuildCalc for free! If, instead, you see BuildCalc’s price and you are sure you purchased BuildCalc then most likely you are not logged into the same Google account you were when you purchased BuildCalc. Be sure that this Android device is associated with that Google account. In other words, is the email account on this device the same as it was when you purchased BuildCalc?
Tap on the BuildCalc cell (as shown in the above screen shot) and then tap on the [Install] button in the BuildCalc product page.
Tap the [Accept & download] …

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I tried to contact you but you didn’t reply!

The only time I don’t reply is when an invalid email address is entered into the contact form.  So, if you don’t hear from me, please send an email directly to me at 


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iPad: the [Done] button is missing!

If you are running BuildCalc on an iPad and the [Done] button is missing on the “enhanced” and/or the “advanced” function screens, here is what is going on: Older versions of Apple iOS have a bug that prevents screens like this from being displayed correctly WHEN the screen is locked in landscape orientation. Usually, one would lock the screen in landscape orientation for a reason, so I’m not going to tell you the fix is “unlock the screen orientation”. Rather, the easiest fix is to update to the most recent version of iOS. The next time you go to sync your iPad with iTunes, iTunes should automatically ask you if you want to do this.

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Is there a way to make BuildCalc easier to see in direct sunlight?

I’ve had this problem too.  When you’re in the field, all of these smart phone devices are hard to see.   Tablets are worse!  Getting an iPad pushed me over the edge on this one.  As of version 2.1 (now available on Android and should be on iOS next week), you can switch the display to “Daylight Display Mode” by (1) pressing and holding the ⓘ symbol (in the top left corner) and then tapping on the [+] key.  BuildCalc will go from a display as shown on the left to that on the right … which looks great in full sun.


Repeat the above steps to turn off “Daylight Display Mode”.  Also, you can switch “Daylight Display Mode” by going to BuildCalc’s preferences via [Conv] [Prefs].

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Is there a tablet version?

Yes.  BuildCalc looks really great on both Android and Apple tablets.   Especially the Layout Drawings (they’ll knock your socks off!).

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Thousands separator: How do I get 12634 to display as 12,634?

Try this:

Tap [Conv] [Prefs]
You should now be at the Preferences screen.  Scroll down to the “Thousands Separator” cell.
Tap the toggle switch in the “Thousands Separator” cell to turn it “ON”
Tap the [Done] button at the bottom right of the screen
Any new entries or results will use a thousands separator.

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What is the most recent version?

Version 2.1 is the most recent version and is now available for Android from the Android Market.   You can verify what version you using by either:

BuildCalc’s in-app “info” screen
In iTunes Library, in the Applications folder, right click on BuildCalc and then click on “Get Info” in the pop-up menu.

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Is there a manual?

 To the right is a link (warning: it’s 8.3MB) to the latest BuildCalc manual. It is formatted like a reference document and it contains tutorials and instructions for every function. A lot of effort has gone into making it easier for you to do your construction math … so if you see anything that could be better – big or small – please let me know and we’ll work together to make it right.

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How do I upgrade to the latest version of BuildCalc?

Upgrades to BuildCalc are free. Instructions are situational, so take a look at the list below to see which approach is best for you.

For iOS devices (iPhone, iPod touch, iPad):

on your device: Go to the [App Store] app and tap on the [Updates] icon on the bottom right corner of the menu bar.  If BuildCalc is listed, there is an update.  Tap on the BuildCalc icon and follow the instructions to update.
on iTunes on your PC / Mac:  go to iTunes and, in the list on the left side of iTune you should see a listing like shown here on the right.   Click on Applications (under Library).   Towards the bottom right of iTunes, you will see something like this:  .  Click on the text “Updates Available”.   This will take you to a special section of the iTunes store called “My App Updates”.  If own BuildCalc but do not have the most recent version, you will see a link to upgrade it there.

For Android devices:

Go to the Android Market app on your device and tap on the “My Apps”  link.  All of the apps that you have downloaded from the Android Market will be there, starting with the apps that have updates available.  Find BuildCalc on that list.  If BuildCalc indicates “Update” or “Update (manual)” tap on the BuildCalc cell.  Follow the instructions to update.

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Is there a demo or trial version?

Yes, there is a demo version of BuildCalc – as a page here on this website.  It runs in the browser so you there’s nothing install (but it uses Adobe Flash, so unfortunately you can’t run in on your iOS device).

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How do I calculate the diameter or radius of an arc?

If you know two of the following about an arc, you can calculate the diameter or radius for that arc.

•Segment Height (rise)
•Chord Length (run) of an arc.
•Arc Angle

Here are some examples:

Example 1:
Find the radius of an arc given a Segment Height (Rise) of 2m and a Chord Length (Run) of 6m

You Input




2 [m] [Rise]


BuildCalc Displays






Example 2:  Find the diameter of an arc given a Segment Height (Rise) of 6ft 2in and a Chord Length (Run) of 20ft 6in…

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Where can I get more help or instructional information?

There are six sources of instructional information for BuildCalc that you may find useful:

Contact me!  I listed this one first because, in most cases, this is the easiest and fastest way to get what you need to be up and going.  However, the following options are all great as well.  You can reach me by any of the following:

• the contact form, at the bottom of this page

• by emailing me at: 

Help on the Advanced Functions (ones not found on a common calculator) can be found by either:

• pressing and holding for 3 seconds the key for which you wish help

• pressing the ( i ) button at the bottom of the results screen for that function

General Help: Doing the same (pressing and holding for 3 seconds) on keys found on common calculator (like numbers, arithmetic symbols, etc.) will display a menu of general help items.
“On-the-spot” help for the Advanced Function Inputs:  The Stair, Compound Miter, Baluster and Hip/Valley Rafter, and Diagonal functions offer on-the-spot help for each input parameter to guide you through your calculation.
The BuildCalc Manual:  The latest version can be downloaded at http://BuildCalc.com/manual.pdf
Study Guide: for more of a self study work book approach to learning BuildCalc you may wish to try the following documentation for the Construction Master® Pro – the calculator in which BuildCalc emulates and is key compatible (100% so when Advanced Function Mode is set …

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Where are the [SIN] [COS] and [TAN] keys?

You can display the trig keys two ways:

•Horizontally swipe your finger across the  [Length] [Width] [Height] keys
•Goto your device’s settings, scroll to the bottom and select BuildCalc. The third setting should be “Trig Keys”. Switch it ON.

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I can’t find the [Length] [Width] [Height] keys … where did they go?

It is likely that you have unintentionally switched between linear dimension and trigonometric keys. To switch back, either:

•Horizontally swipe your finger across the  [SIN] [COS] [TAN] keys
•Goto your device’s settings, scroll to the bottom and select BuildCalc. The third setting should be “Trig Keys”. Switch it OFF.

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I can’t find the [Yard] [Feet] [Inch] keys … where did they go?

It is likely that you have unintentionally switched between imperial and metric length keys. To switch back, either:

•Horizontally swipe your finger across the  [m] [cm] [mm] keys
•Goto your device’s settings, scroll to the bottom and select BuildCalc. The fourth setting should be “Metric Length Keys”. Switch it OFF.

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I can’t find the [m] [cm] and [mm] keys … where did they go?

What happened to the [m], [cm] and [mm] keys?  They have been replaced by [Yard], [Feet] and [Inches].
You have unintentionally switched between imperial and metric length keys.  To switch back, either:

•Horizontally swipe your finger  across the [Yard] [Feet] [Inch] keys
•Goto your device’s settings, scroll to the bottom and select BuildCalc.  The fourth setting should be “Metric Length Keys”.   Switch it ON.

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© 2011 42nd Parallel. Construction Master® is a registered trademark of Calculated Industries and is no way affiliated with 42nd Parallel or BuildCalc. Apple®, iPhone®, iPad®, iPod touch®, iTunes® and the Apple Logo are registered trademarks of Apple. Android™ is a trademark of Google Inc. Portions of this page are reproduced from work created and shared by Google and used according to terms described in the Creative Commons 3.0 Attribution License.