How to visually represent file size

Question

This will be a bit subjective, I'm afraid, but I'd value the advice of the Collective.

Our web application lists documents that users can download; standard file navigator stuff:

Type   Name     Created       Size
-----------------------------------
PDF    Doc 1    01/04/2010    15 KB
PDF    Doc 2    01/04/2010    15 MB

Currently we list the file size as text, but I'd like to improve this by having some way of showing visually whether the file is tiny, normal or huge.

The reason for this is so that users can scan the list quickly and spot files that are likely to take a long time downloading.

My options currently are:

• Bigger font sizes for bigger files (drawback: the layout can become untidy)
• Icons (like a wi-fi signal strength indicator; drawback: harder to scan)
• Keep all sizes in KB so the number of zeroes indicates size (drawback: users have to calculate the "friendly" size in their heads)

I know this is quite a minor thing, but I'd appreciate anyone's thoughts on the matter!

Edit: Thanks for the answers!

From what you've said, I think that:

• I really like Robert's idea of telling users roughly how long it will take to download the file
• As someone pointed out, if I use a bar or "signal strength" icon, that gives the impression of a "maximum" file size
• I like shading the text - stronger for larger files

I'm going to go with a combination approach:

• Uniform font size
• Darker text for larger files
• A tooltip telling users roughly how long it will take to download
• A tiny piece of text, in brackets, after the size, describing how big it is, e.g.:

15 KB (tiny)
2 MB (small)
20 MB (big)
300 MB (huge)

I'll see if I can put a screenshot on here of how it looks when I've got a prototype. Again, thanks for the feedback!

Answer 1

If it were me, I would show the size of the file in the usual way, but also display an estimated time to download (Assume 1.5 MBit DSL for your calculations).