Software development is a tough business when clients want to know how much something will cost. It’s certainly reasonable for our clients to want to understand how much budget they need to allocate for a project, and I always do my best to provide them with estimates to the best of what we know.

However, sometimes it’s hard to convey to them that (1) an estimate is almost never right, and (2) there are certain things where it’s actually impossible to estimate what it’ll take to accomplish their goal. Sometimes this is because we’ve never used the technology; other times it’s because they just don’t know quite what they want.

Just now I got hit with the latter. Here’s part of an actual client email:

At high level I see you will have to perform following tasks (and probably much more)…

[bullet list of three things]
For budget purpose, can you please give me a high-level cost estimate to make these changes (as well as other changes)?

This happens to be a fairly major project that will affect an entire product line. My client has managed to collapse the entire thing down to three bullet points, and “probably much more”. And I’m supposed to estimate this…?

Perhaps I should give my standard reply:

One million dollars will certainly cover it.