
Ask HN: Where do you do quick back of envelope calculations? - adamlangsner
Before Apple killed the Dashboard in Catalina. I had this widget called FormulaCalc that I loved.<p>It was very basic, screenshot below. It had two long text fields on top of each other. You&#x27;d enter a mathematical expression in JS in the top field (e.g. &quot;3 + 4 &#x2F; ( 5 * 0.9 + pi) + pow(2, 4)&quot; ) and as you typed it would auto-generate the result in the bottom field in real time. I would have several instances of this widget in my dashboard so I could quickly and easily do simple calculations or do multipart calculations, copying the result from one widget into the input field of another.<p>I&#x27;d use it constantly for things like measuring stuff for frontend work, doing some rough analytics from db queries, or even just back of envelope budgeting &#x2F; tax stuff. Using it was so automatic and immediate that it became such an essential tool.<p>Screenshot: http:&#x2F;&#x2F;www.mindlessflash.com&#x2F;formula_calc.png<p>Since I upgraded my OS I&#x27;ve been using the evaluator in Spotlight and the calculator app on my phone and it&#x27;s not as good because you can only work with one formula at a time. So I guess I have two questions:<p>1. How do you do rough calculations day to day, what tools do you use and are you happy with them?<p>2. Do you know of any products &#x2F; solutions that are similar to the dashboard widget I described above?
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perilunar
On the back of an envelope?

Seriously: with a pen, a scrap of paper, and a calculator.

If I want to keep the calculation I'll copy it to a plain text document or to
a spreadsheet, or copy it to a notebook.

Also, if you have a browser open, you can just type equations into the console
(using JS syntax):

    
    
      > 3 + 4 / ( 5 * 0.9 + Math.PI) + Math.pow(2, 4)
      < 19.52345108949519
    
    

Edit: or just open Terminal, type 'python', and use in interactive mode:

    
    
      >>> import math
      >>> 3 + 4 / ( 5 * 0.9 + math.pi) + math.pow(2, 4)
      19.52345108949519

~~~
adamlangsner
Do you find that this workflow disrupts your flow at all when you're working?
Also, do you have any difficulty keep track of all the different calculations?

~~~
perilunar
No it's fine. I almost always have a browser and a text editor open, so cut &
paste between them is quick. console keeps all the calculations until cleared.
If I have a geometry problem I always sketch a diagram with pen and paper
first.

(btw the Mac Calculator.app has a 'paper tape' feature that also keeps a
record of calculations. ⌘T)

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Wowfunhappy
Formula Calc sounds great, where can I download it? I'm enjoying life on
legacy OS X versions over here! 8)

Edit: Answering my own question:
[https://www.apple.com/downloads/dashboard/calculate_convert/...](https://www.apple.com/downloads/dashboard/calculate_convert/formulacalc.html)

~~~
adamlangsner
What do you currently do for quick calculations?

I uploaded a copy to my s3 bucket:
[https://www.mindlessflash.com/FormulaCalc.wdgt.zip](https://www.mindlessflash.com/FormulaCalc.wdgt.zip)
remove the .zip extension before opening on it.

~~~
Wowfunhappy
I currently use Spotlight, but it's super non-ideal. I'll often dismiss
spotlight and then realize I forgot the result. (I really hate what they did
to Spotlight in Yosemite—it's overloaded and thus worse at its original
purpose of searching the filesystem.)

I also recently bought Soulver
([https://www.acqualia.com/soulver](https://www.acqualia.com/soulver)), which
is great but not quite as quick as a dashboard widget.

Thanks for the modified upload—I realized the version on Apple's site has a
visual glitch with the search bar length. I also found this version, which
makes you hint enter before you can see the result, but feels more polished.
Can't tell if there's any relation.
[https://www.apple.com/downloads/dashboard/calculate_convert/...](https://www.apple.com/downloads/dashboard/calculate_convert/formulacalcwidget.html)

~~~
adamlangsner
Thanks. I'll check out soulver, it seems a bit linear though. I don't know
about you but I'm looking for something that's more like plugging inputs into
outputs and wiring up calcs than doing them line by line.

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cepp
Not exactly what you were asking for, but I really like Soulver [1]. It's a
natural-language-ish calculator. The interface is similar to a REPL where you
can name/recall and evaluate. The only downside is it's a bit pricey at $30.

[1] [https://soulver.app](https://soulver.app)

~~~
adamlangsner
Thanks! Is there anything you dislike about soulver other than the price?

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cepp
There's only one thing I'd mention which is that version 3 changed the
document model.

In version 2 you could make independent files and put them anywhere. It seems,
though I may be wrong as I haven't used v3 much, that they want you to keep
all your files in one central location and not have independent Soulver files.

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ToFab123
I use wolframalpha.com

Here is the result of the equation from the OP
[https://www.wolframalpha.com/input/?i=3+%2B+4+%2F+%28+5+*+0....](https://www.wolframalpha.com/input/?i=3+%2B+4+%2F+%28+5+*+0.9+%2B+pi%29+%2B+pow%282%2C+4%29)

~~~
adamlangsner
what if you need do multi-step calculations? do you find wolframalpha agile
enough or is it cumbersome to use for quick things?

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omarhaneef
Excel. If there was a faster loading "tiny spreadsheet" that would just pop
open, I would love it.

~~~
adamlangsner
Thanks! What type of quick calculations do you typically do in excel?

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omarhaneef
I do many. Sometimes I am on a call and someone mentions numbers I have to
track. Sometimes I have to do a series of discount rates over time. I look at
a lot of ratios. Even when I do complicated calculations, I like to look at
the intermediate steps over time.

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bananicorn
Since I'm mostly in the terminal, I just pop up a Lua prompt and do the
calculation there - any repl will do, honestly :)

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kody
Like a few others here, I typically use an interactive Python console.

