# Need a free date calculator

**URL:** <https://boards.straightdope.com/t/need-a-free-date-calculator/233802>\
**Category:** Factual Questions\
**Created:** [March 11, 2004, 11:41pm UTC](https://boards.straightdope.com/t/need-a-free-date-calculator/233802 "2004-03-11T23:41:48Z")\
**Posts on this page:** 7\
**Page:** 1

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**Author:** ![Chefguy](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chefguy/32/138_2.png) [@Chefguy](https://boards.straightdope.com/u/Chefguy)\
**Post date:** [March 11, 2004, 11:41pm UTC](https://boards.straightdope.com/t/need-a-free-date-calculator/233802/1 "2004-03-11T23:41:48Z")

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I need a date calculator that I can download, where I can enter the start date and the duration and get the resulting end date. I’ve looked, but no can find. There are plenty of the type where you enter two dates and it tells you the duration, but that’s not what I need. Help, please.

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**Author:** ![Enginerd](https://avatars.discourse-cdn.com/v4/letter/e/bcef8e/32.png) [@Enginerd](https://boards.straightdope.com/u/Enginerd)\
**Post date:** [March 11, 2004, 11:54pm UTC](https://boards.straightdope.com/t/need-a-free-date-calculator/233802/2 "2004-03-11T23:54:36Z")

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I don’t know where you can get freeware to do this, but I have to do it all the time. Do you have Excel? You can calculate it with

> [@](#):
>
> ={Start Date} + {Time in Days}

If you don’t have Excel, hopefully someone else will be along soon to point you to what you’re looking for.

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**Author:** ![Chronos](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chronos/32/134_2.png) [@Chronos](https://boards.straightdope.com/u/Chronos)\
**Post date:** [March 12, 2004, 12:03am UTC](https://boards.straightdope.com/t/need-a-free-date-calculator/233802/3 "2004-03-12T00:03:22Z")

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If you can wait until Saturday or so, I could cobble one together for you. I already have some programs for converting calendar dates to JD and back; what you want could be trivially built out of those. What’s your operating system?

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**Author:** ![Chefguy](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chefguy/32/138_2.png) [@Chefguy](https://boards.straightdope.com/u/Chefguy)\
**Post date:** [March 12, 2004, 12:11am UTC](https://boards.straightdope.com/t/need-a-free-date-calculator/233802/4 "2004-03-12T00:11:53Z")

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> [@Enginerd](#):
>
> I don’t know where you can get freeware to do this, but I have to do it all the time. Do you have Excel? You can calculate it with
> 
> If you don’t have Excel, hopefully someone else will be along soon to point you to what you’re looking for.

I have excel, but typing in your formula as written gets me gibberish. Suggestion?

**Chronos** : It’s Windows XP Pro.

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<div class="post-metadata">

**Author:** ![Enginerd](https://avatars.discourse-cdn.com/v4/letter/e/bcef8e/32.png) [@Enginerd](https://boards.straightdope.com/u/Enginerd)\
**Post date:** [March 12, 2004, 12:29am UTC](https://boards.straightdope.com/t/need-a-free-date-calculator/233802/5 "2004-03-12T00:29:42Z")

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Yeah, I should probably try it before I tell people how to do it - sorry about that. Attempt #2:

Enter the starting date in one cell.  
In another cell, enter =(Cell1)+(# of days)

I actually tried it this time, and it works on my end.

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<div class="post-metadata">

**Author:** ![Chefguy](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chefguy/32/138_2.png) [@Chefguy](https://boards.straightdope.com/u/Chefguy)\
**Post date:** [March 12, 2004, 12:33am UTC](https://boards.straightdope.com/t/need-a-free-date-calculator/233802/6 "2004-03-12T00:33:21Z")

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> [@Enginerd](#):
>
> Yeah, I should probably try it before I tell people how to do it - sorry about that. Attempt #2:
> 
> Enter the starting date in one cell.  
> In another cell, enter =(Cell1)+(# of days)
> 
> I actually tried it this time, and it works on my end.

Wow, magic! Thanks.

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**Author:** ![galt](https://avatars.discourse-cdn.com/v4/letter/g/35a633/32.png) [@galt](https://boards.straightdope.com/u/galt)\
**Post date:** [March 12, 2004, 1:23pm UTC](https://boards.straightdope.com/t/need-a-free-date-calculator/233802/7 "2004-03-12T13:23:07Z")

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Alternately, if you want something that doesn’t require you to have excel, create a text file called calc.hta and paste this code in it:

```auto

<html>
<head>
<script language="javascript">
window.resizeTo(150,250);
function Go()
{
	var days = new Number(document.all.inputform.duration.value);
	var start = new Date(document.all.inputform.date.value);
	var end = new Date(start.valueOf() + days * 24 * 60 * 60 * 1000);
	document.all.inputform.end.value = DateStr(end);
}
function Init()
{
	document.all.inputform.date.value = DateStr(new Date());
	document.all.inputform.duration.value = 0;
	Go();
}
function DateStr(d)
{
    return "" +
          (d.getMonth() + 1) + "/" +
           d.getDate() + "/" +
           d.getYear();
}
</script>
</head>
<body onload="Init();">
    <form name="inputform" action="">
    Date:<br>
        <input type="text" id="date" size="10"><br>
    Duration:<br>
        <input type="text" id="duration" size=5>days<br>
        <input type="submit" onclick="Go(); return false;" value="Go"><br>
    End date:<br>
        <input type="text" id="end" size="10">
    </form>
</html>

```