 <p>Excel evaluates both parts of an <code>OR</code> expression independent if the first part is true. So <code>A1&lt;0</code> and therefore the <code>OR</code> function result in an error if <code>A1</code> contains an error.</p> <p>You can try something like that:</p> <pre><code>IF(ISERROR(A1),"Y",IF(A1&lt;0,"Y","N")) </code></pre>