The Honeywell FC200E1037 whole-house filter is labeled “20x25x4” but actually measures 19.875 x 24.75 x 4.375 inches. Unlike 1″ filters, 4″/5″/6″ whole-house filters don't share one universal nominal-to-actual conversion — always match by brand and model, not just the printed size.

Depth reported as either ~4.375" or ~3.75" depending on source — check your old filter. Sources disagree on this measurement — treat as approximate and confirm against your old filter.