Posted on Tue 24 October 2017

Numi calculator

Numi conversions

I've been using a cool calculator on my Mac recently that I want to share with you. It's called Numi. Numi can do lots of really awesome things, and personally I'm barely scratching the surface, but I'll just share with you some of the reasons I love it and let you discover everything else it can do on your own.


One of the most common times I use a calculator app is when I write up monthly reports of business stats. I need to work out various percentages, and how much different numbers have increased or decreased compared to last month. Numi lets me create variables, which makes this process a lot easier.

(If you're not a developer and don't know what I mean by variables, it's basically the idea of giving an object or a value a name, so you can keep referring to it. Check out the examples below.)

For instance, I could do something like this:

lastMonthBlogVisitors = 2,500
thisMonthBlogVisitors = 3,000
difference = thisMonthBlogVisitors - lastMonthBlogVisitors

And here's a real example of some old calculations where I used variables:

Numi variables

Using variables means I don't have to keep in my head what each value is, so I can keep referring back to the same values more easily. (Developers with a keen eye will see how my introduction to programming being in Objective-C is shining through in my delightfully descriptive and not at all concise variable names.)

Numi also does conversions. It's a calculator and conversion app in one. And doing conversions is super easy. Here are some examples that will work in Numi:

$30 usd in aud // I use this one a lot when I'm doing online shopping!

3:30 pm BST in SGT // It even does TIME ZONE conversions! Amazing!

now in New York

7 inches in cm

1.5 tea spoons in ml

2 pounds in kg

Numi conversions

Isn't that amazing? I use it for conversions all the time. I have a keyboard shortcut set to show Numi, so I can bring it up, type a conversion, and go back to work (or shopping) without my hands leaving the keyboard.

Numi pretty much works like a little notepad. You can write whatever you like into it, and if it understands, it'll compute it for you. But this means you can also add notes about your calculations and export or copy the entire Numi file you've created. The files are exported with the .numi suffix, but they're really just plain text, so you can open them in any editor you like. You can add comments and headings to Numi to explain the calculations you've done using syntax like this:

# This is a heading

weight = 50 "Add a comment here"

// This is a full-line comment

Numi also makes it easy to do some cool things with your numbers, like finding the average or grabbing a reference to the result of the previous line. Check out some examples:

1500 cm in inches
prev * 2
// "prev" lets you use the result of the previous line without explicitly making it into a variable

amount1 = 5 * 10
amount2 = 45
// "average" calculates the average of all lines above until an empty line

amount1 = 10
amount2 = 7 * 15
// "sum" calculates the total of all lines above until an empty line

Numi functions

And for working with percentages, which I often do in my monthly reports, Numi's syntax is really easy to use. Here are some examples:

10% of 300

10% off 37.99

1500 as a % of 3200

Like I said, I'm only scratching the surface. Numi also has lots of support for sciencey stuff I don't understand and trigonometry and so on. And you can even write extensions for Numi. But even with just what I've mentioned here, I find Numi to be super useful as an everyday calculator and converter app.

If you use Alfred, you can also install the Alfred workflow for Numi and do calculations via Numi (except time zone conversions) inside Alfred! How about that.

using Numi in Alfred

While Numi is in beta it's totally free. If you do conversions or calculations on a Mac regularly, go check it out. Oh, and it even has a night mode/dark theme!

(In case it's not obvious, I wasn't paid or even asked to write this. I just use this app a lot and think it's cool.)

P.S. I make some stuff you might like: Exist, a personal analytics app to help you understand your life, and Larder, a bookmarking app for developers.

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