The thing you actually want is rejection sampling: <a href="https://en.wikipedia.org/wiki/Rejection_sampling" rel="nofollow">https://en.wikipedia.org/wiki/Rejection_sampling</a>.<p>That Wiki page makes it sound very complicated but for this purpose our implementation can be laughably simple which has the advantage that you know why it works and can maintain it properly with confidence.<p>Get suitably large inputs, for example if you're trying to pick integers between 2 and 11 inclusive, a nibble (half a byte) would be fine. Now, is the random input in the range you wanted? If so, you've got your answer. If not, throw this random input away and get more.<p>Too many programmers act as though random numbers were a precious resource.