Nowadays the answer is obvious: go to [reputation audit](http://stackoverflow.com/reputation) and look for the `[..]` for that day.

> _Jeff Atwood said_: If the value is capped, it will appear in brackets like `[3]` so.

### References

* [How do I audit my reputation?](http://meta.stackexchange.com/questions/43004/how-do-i-audit-my-reputation)