# Is it better to mix 'km' and 'm', or just stick to km and one way of displaying data

I have a list of distances in a dropdown, as in the examples below.

Is it better to stick to km across the board, eg:

0.1km
0.5km
1km
3km
5km
10km
50km
100km
200km

or to use m for the smaller values and km for the larger values? eg:

100m
500m
1km
3km
5km
10km
50km
100km
200km

• Who is your audience? – maxathousand Apr 6 '17 at 22:14
• What are the extreme values? If its between 0.1km and 200km, definitly stick with km completely. If you have smaller distances, variable units are probably best. – JanErikGunnar Apr 7 '17 at 1:14
• @maxathousand Audience is someone who uses Twitter professionally, similar to a Hootsuite or SproutSocial user – Eleanor Apr 7 '17 at 22:36
• @JanErikGunnar These are all the values including extremes. Thanks for your feedback! – Eleanor Apr 7 '17 at 22:37

I have no extensive research to back my opinion, but I can tell that using variable units feels more friendly and easier to understand. In other words, it's a better "experience".

I don't know about the context of your application, I'd check where your users are likely to get this information from, and what is the format they'd get it.

For example, if users select a value from your dropdown after using an app to track how far they walked, if under 1km the app displayed meters, I'd follow the same format and display meters as well.

At the end you want to decrease the complexity and amount of think your user has to do in order to accomplish the task you're giving them.

If your lowest value was .5km perhaps sticking with km would be ok, but I have a feeling that people don't naturally think in fraction (0.25km, 0.1km).

Another way to think about it is how you would say that to someone, like: "The bakery is just 0.3km from here" vs "The bakery is just 300m from here."

In summary, I'd use variable units, as Google Maps does it and most of the time when I work with distances, users are getting the values from there.

• I totally agree. @Eleanor, whatever you chose remember to sort the options from the smallest distance to the greatest, not by the numbers only. – Mike Apr 7 '17 at 20:15
• Thanks for your thoughts @matheus. The context is within a professional app for Twitter users, where they would be using this dropdown to set a radius to search for Tweets. I hear what you're saying in terms of decreasing the amount that the user needs to think. If the first thing they see on the list is 0.1km, that isn't the most natural form of that information. 100m is probably easier to understand. – Eleanor Apr 7 '17 at 22:40