To calculate the leasing closing ratio, you can use the following formula:
\[ \text{Leasing Closing Ratio} = \left( \frac{\text{Number of Applications}}{\text{Number of Tours}} \right) \times 100 \]
In this case, you have taken 4 applications from 16 potential renters who toured the property:
\[ \text{Leasing Closing Ratio} = \left( \frac{4}{16} \right) \times 100 \]
Now, calculate it:
\[ \text{Leasing Closing Ratio} = \left( 0.25 \right) \times 100 = 25% \]
Therefore, your leasing closing ratio is 25%.