Filter Measurement Helper

Follow these quick steps to learn how to measure your AC filter correctly so you know what size to buy next.

1. Where is your filter located? Select...Return grille (ceiling or wall)Inside the air handlerIn the attic return box 2. Measure the length Select your measured length...15–17 inches18–21 inches22–25 inchesOther 3. Measure the width Select your measured width...10–12 inches13–16 inches17–20 inchesOther 4. Measure the thickness Select your thickness...1 inch2 inches4 inches Show Me What This Means