In this case, we want to show if the value is in Miles or Kilometers:


  • A good part of the answer depends on whether you're dealing with occasional or frequent users. Occasional (novice) users will find having the units in the cell good because they don't need to refer to the column heading for understanding. Frequent (expert) users will find having the units in the cell bad because they know the units and find them just to be noise.
    – Bevan
    Jul 8, 2012 at 8:59

2 Answers 2


Having the units in the data section makes it more discoverable since it is displayed right next to the item it relates too. Users are probably more likely to look right at the table content since that's the interesting stuff. I can see that the units make it look busier but that can be addressed by making units less prominent visually.

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  • 2
    Might I suggest that you at least align the units in the table, and also make sure the numbers themselves are aligned at the decimal separator? In your example, I find it hard to at a glance decide that Jack Jump is much closer than Kat Likeclimb. That little dot between the 3 and the 4 is too easy to miss at first view, while when aligning the 3 with the 0 of the 20 the difference becomes obvious immediately. Aligning the units allows for quick scanning of the units as well, and more rest if they are all the same.
    – André
    Jun 26, 2012 at 8:41

Putting units in the data section makes it busier and harder to "parse" at a glance. But there's one complex scenario - when your data varies a lot - e.g. when you need to print precise file sizes that vary from a couple bytes to several Gb.

My rules of thumb are:

  1. If unit does not change - print in the header to have cleaner data section.
  2. If possible, strive to use the same unit (e.g. if you print sizes that vary from mm to km, use meters - this way it will be easier for the user to compare values at a glance).
  3. Print units in the data section if different units are used.
  4. Never mix measurement systems.

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