 <p><code>int</code> does not round -- it finds the floor (truncates the fractional part).</p> <pre><code>&gt;&gt;&gt; n = 8.92138 &gt;&gt;&gt; '%.42f' % n # what n really is '8.921379999999999199644662439823150634765625' &gt;&gt;&gt; 100000 * n # result is slightly lower than 892138 892137.9999999999 &gt;&gt;&gt; int(100000 * n) # int takes the floor 892137 </code></pre>