 <p>Well, the fibonacci series grows (approximately) exponentially with a ratio of 1.618 (the golden ratio).</p> <p>If you take the log base 1.618 of <code>Integer.MAX_VALUE</code> it will therefore tell you approximately how many iterations you can go before overflowing....</p> <p>Alternatively, you can determine empirically when it overflows just by doing the calculations....</p>