Date Calculator

Date Calculator calculates the numberDate Calculator Logo of days, weeks, months or work days between 2 dates. If the duration is given, one of the dates is calculated. The field that was changed first is calculated. For example, if you change the end date, then the start date and then change the duration, the end date is calculated. When the program first starts, the calculation order is; start date, end date then duration. Changing the units of the duration does not affect which field is calculated.

Press the start or end date to bring up a DatePicker to set that date. Press the Today button beside the start or end date to reset that date to today. Check the Lock check box beside the start or end date to prevent that date from being calculated.
Press the Duration number brings up a dialog box to input an integer duration. Non-integer duration are not allowed. Press the down arrow beside the Duration units brings up a dialog box which allows you to choose between days, weeks, months and work days. Press the + or – buttons to decrease or increase the duration number by 1.
By default, the start day is not included in the count. The end day is. This can be changed in the Settings or by pressing the StartDay is Not Included toggle button.
Press the Save Data button to save the dates, duration and other settings currently on the screen to memory.
Settings allow the Default Duration units to be used when the app starts to be set, which days of the week are work days and whether to use saved data when the app starts.
Does not work with dates prior to the year 1900 or after the year 2100 due a limitation of the Android date picker.
Download Date Calculator from Google Play
Download Date Calculator5 from Google Play
The current version of Date Calculator is 1.2.7. This version adds more choices for the date display format and fixes the black text on black background for Android 5 again.(Jan. 16/16).
Date Calculator is currently financed by Google AdMob advertisements.

Version History

Version 1.2.3 adds choices for the date display format and fixes the black text on black background for Android 5.(Nov. 1/15).

Version 1.1.9 fixed an exception caused by the save data button and removed the date picker dialog by Simon Vig.(Jul. 9/13).

Version 1.1.7 contained the date picker dialog from Simon Vig which I could not get to work after upgrading the SDK.(Jul. 5/13)
Version 1.1.6 adds a save data button to allow the user to set the data that the app starts with. The Home key on the phone does not clear the app from memory so if you use the Home key to close the app the saved data will not be used when the app is restarted.(Apr. 7/13).
Version 1.1.5. changes from week days to work days to support users around the world and adds the ability to choose which days of the week are work days. There is bug in the Jelly Beans Date Picker Dialog so the Date Picker Dialog is replaced with the Date Picker Dialog from Simon Vig Therkildsen at github.com/SimonVT (Jan. 18/13).
Version 1.1.4 adds a trap for NumberFormatException errors when typing the Duration and updates the screen layout for larger screens (Aug.22/12).
Version 1.1.1 adds Include Start Date and Default Duration units to Preferences (Apr.27/12)
Version 1.1.0 adds a button which opens a dialog box for the user to type in the duration
(integer only) (Feb.3/12).
Version 1.0.9 adds a trap for NumberFormatException errors when changing between portrait and landscape (Jan. 27/12).
Version 1.0.8 adds a trap for NumberFormatException errors from the plus and minus buttons (Jan. 13/12).
Version 1.0.7 was the first version released to the public (Dec. 4/11).

Issue Log

Date Issue Resolution Raised by
January 11, 2012 NumberFormatException from plus and minus buttons Error trap added in version 1.0.8 to change incorrectly formattted numbers to 0 (zero) Google User
January 24, 2012 NumberFormatException when changing between portrait and landscape Error trap added in version 1.0.9 to change incorrectly formatted numbers to 0 (zero) Google User
February 1, 2012 Add the ability to type the duration instead of using the plus and minus buttons Button added in version 1.1.0 to bring up a dialog box for the user to type the duration in (integer only). Mark Lasby
March 5, 2012 Cannot input dates prior to the year 1900 or after the year 2100. Cannot be resolved. This is a limitation of the Android DatePicker. Google User
April 2, 2012 Add option to include or not include start date in calculation Include Start Date added to Preferences in version 1.1.1 Glyn Garratt
April 19, 2012 Add option to change default duration units Default Duration units added to Preferences in version 1.1.1 Ian Webb
July 2012 Add list of holidays to be excluded from calculations. Google User
August 20, 2012 NumberFormatException when parsing a duration containing a comma, ie 10,213 Error trap added in version 1.1.4 to change incorrectly formatted numbers to 0 (zero) Google User
August 23, 2012 Use Sunday only or Friday and Saturday as weekend days for calculating weekdays Changed from weekdays to work days in version 1.1.5 Fernando Ossandon
October 18, 2012 Week and month are off by 1 if start date included code fixed in version 1.1.4 Google User
March 29, 2013 Add ability to save and restore data between uses Save Data button added and Restore Data added to Preferences in version 1.1.6 Karl Edelsten
July 5, 2013 Null Pointer Exception thrown by saved data button. Exception trap fixed in version 1.1.7 Google User
July 6, 2013 Add options to support different date formats  Added in version 1.2.3 Alexander Bogdanovich
April 9, 2014 Add “Weekends” to duration list Michael Higgins
April 16, 2015 Fix black text on black background for Android 5  Fixed in version 1.2.3 Matthew Vaughan, David York, Five Hens Farm

16 thoughts on “Date Calculator

    • 1. No donating does not remove the ads.
      2. The feature to exclude holidays has not been developed yet. There is no plan to implement this feature any time in the foreseeable future.
      3. Only one set of dates can be saved at this time. There are no plans to expand this feature any time in the foreseeable future.

  1. When I specify one date in the 20th century and the same date in the 21st the number of days is off by 1. Rather than 36525 the calc indicates 36524. At first I thought it was a missing leap day on February 29, 2000, but you do account for it in calculating February 28, 2000 to March 1, 2000.

    Just thought you should know.

    Take care and have a great day.

    Walt

    P.s. I like the product.

  2. Great app. I updated to lollipop and now the date and calculated fields don’t show up. . If I press them I can see the date, when I release it, the field goes to black. . Is there an update coming

  3. Hi Mark,

    Date Calculator is a great little app which I use all the time. After upgrading to Android 5.0 on S5 the date fields are blank. Looks like black text on a black background. Tapping on the field will allow you to see the dates briefly as the text turns grey before the date input box is displayed.
    Let me know if you’d like a screenshot.
    Thanks for making a neat and simple app.
    Cheers,
    Matt

    • I cannot get the ads to work for Android 5. After I update for Android 5 and remove the ads, the app does not work for Android 2 devices. Until such time that the install number for Android 2 drop to something insignificant, I have to find a stop gap solution. While I am figure this out, I will email an Android 5 version without ads to anyone who asks for it. Do not ask for the Android 5 version if you are not using the app on an Android 5 machine because it will not work.

  4. Please send Date Calculator 5.x version for my 2013 Google Ńexus 7. I’m running lollipop 5.1.
    Thank you very much Mark it’s a great calculator
    Best,
    Clark Leyva

  5. Love the app. Been using it for a while now since I have a contractor working on a remodel project and want to keep track of how many days he is overdue in finishing the project. What I do know from the app is that I have a START DATE, TODAY DATE AND WORKDAYS. From that information app calculates how many days have elapsed from the start date. However, since my job was to take 21 days I still have to calculate how many days over the completion date has elapsed. Certainty not a big deal but it would be nice if you could allow an optional ESTIMATED COMPLETION date to be factored into the calculation. Just a thought.
    Thank you,

    Gordon

    • The app uses a start date, end date to calculate the duration in days, work days, weeks or months. What I understand you to be asking for is to calculate the duration between 3 date; start, end and current. This is way beyond what the app can handle on one screen.
      By using the save data feature you can save the start and end date to calculate the duration then change the start date to the estimated completion date and calculate how much the contractor is over the completion date.

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