Simple and unobtrusive unit converter for most needs. It can be used as a regular app window but is also available any time in the Today Notification Center (needs to be added after download). Multiple converters are possible in the notification center.

- Angle, Area, Currency, Data Units, Energy, Fuel Efficiency, Length, Mass, Power, Pressure, Speed, Temperature, Time, Timestamp and Volume
- Rates for more than 40 currencies (Sources: Floatrates/Fixer)
- Settings (in menubar) for: light and dark mode; keeping the window on top; thousands separator; decimal places
- Swapping of units
- Share conversion via mail, messages etc.
- Touch Bar support for preferences

Localized to: Arabic, Chinese (Simplified), Czech, Danish, Dutch, English, French, German, Greek, Hungarian, Korean, Indonesian, Italian, Japanese, Norwegian, Polish, Portuguese, Romanian, Russian, Spanish, Swedish, Thai, Turkish.

Why the name Euler: Leonhard Euler (1707 - 1783) was a Swiss mathematician born in Basel, which is also the hometown of the developers

What’s New

Version 1.10

- The last selections for each category in app/widget are now preserved
- Added preferences menu
- Added to length category: Pica

Ratings and Reviews

4.0 out of 5
5 Ratings

5 Ratings

Some-valid-nickname ,


All I wanted was a simple converter, inches to millimeters, and this provides it. Apparently, millimeters were added since Maxx! wrote his review a year ago. This widget sits in the notifications area and as I read imperial dimensions off of a vendor drawing I can enter them into EUC and read off the millimeters I need. No right clicking, no specifying which of a zillion conversions I want, just type and read and type. Easy-peasy.

Seattlite in Uruguay ,

Nice concept but...

I was disappointed that after purchasing and downloading the app, the primary currency I needed was not included. The Uruguayan Peso. Please add!

Maxx! ,

Where’s the metric???

All I needed was to convert inches to centimeters and vice versa, and there’s only Meters… Decimals are cool and all, but would you please add Centimeters and Millimeters? Also the dropdowns don’t stay open.
Really should be free or $0.99 for such a basic widget. But I’d raise this review to a 3 or 4 if it had CM and MM.


Lakehorn AG
6.9 MB

OS X 10.11 or later, 64-bit processor


English, Arabic, Czech, Danish, Dutch, French, German, Greek, Hungarian, Indonesian, Italian, Japanese, Korean, Norwegian Bokmål, Polish, Portuguese, Romanian, Russian, Simplified Chinese, Spanish, Swedish, Thai, Turkish

Age Rating


  • Family Sharing

    With Family Sharing set up, up to six family members can use this app.

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