* Check your owner's manual: This is the most reliable source. The manual will specify the correct sizes for your particular Impala.
* Look at the wipers themselves: The size is usually printed on the wiper arm or the wiper blade itself.
* Use an online auto parts store website: Sites like AutoZone, Advance Auto Parts, or NAPA Auto Parts allow you to enter your vehicle's year, make, and model to find the correct wiper sizes.
Without knowing your trim level, I cannot give you a definitive answer.
