What is the dilution factor if a 0.1*mL volume is diluted to 25.0*mL?

Would it not be $250$?
$\text{Dilution factor"="Final volume"/"Initial volume}$
$= \frac{0.1 \cdot m L + 24.9 \cdot m L}{0.1 \cdot m L} = 250$..........