Last updated: March 2026
Mattresses are flexible and only 8–14" thick on edge. Most windows handle them — the opening just needs to exceed the mattress thickness.
Whether it fits depends on measurements most people get wrong.
Mattress thickness (8–14") on edge = minimum window width. Flexible — bends to fit shorter openings.
Item: King: 76"×80"×10–14". On edge through window: 14" wide × 76–80" height (bendable).
Space: Any window wider than 16" works. Standard: 32"×52" — plenty of room.
Actual clear openings are usually 1–2″ smaller than the labeled size.
Your exact dimensions probably aren't "standard." Small measurement errors cause big problems — 1 inch can be the difference between fitting and getting stuck.
Verdicts are calculated by comparing all 6 item orientations against the space dimensions using verified building code standards. See our methodology
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1 inch can be the difference between fitting and getting stuck.
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Measurements verified by the ItemFits engineering team · Our methodology
Standard sizes say it works — but your measurements are what matter.
A king mattress on edge is 10–14" thick — any window opening wider than 16" works. The mattress width (76") can be bent to fit through shorter windows. Standard double-hung windows handle all mattresses.
For second-floor windows, many people successfully hoist mattresses with rope and a helper above/below. Above the second floor, hire professionals. Mattresses are light (80–150 lbs) but awkward in wind.