 <p>Firstly you don't need to convert <code>decimal</code> to <code>decimal</code>, secondly <code>Text</code> is a <code>string</code> property, so you need to turn <code>result</code> into a <code>string</code>, so replace:</p> <pre><code>txt_WeightGrams.Text = Convert.ToDecimal(result); </code></pre> <p>with this:</p> <pre><code>txt_WeightGrams.Text = result.ToString(); </code></pre>