Free tool Building Code Basements

Egress Window Checker: Will Your Bedroom Window Pass in Ontario?

Enter the clear opening of the window and, for a basement, the window well. The checker tests the same rules an Ontario inspector measures.

Short version: An egress window needs an unobstructed opening of at least 0.35 m² (about 543 sq in) with no dimension under 380 mm (about 15 in), measured with the window fully open. In a window well you also need at least 550 mm of clear space in front of the window.

Check your window

Measure the clear opening with the window cranked or slid fully open: the gap a person actually climbs through, not the frame size.

The rules this checker uses

  • Area: at least 0.35 m² of unobstructed opening with the window fully open.
  • Size: no single dimension of that opening under 380 mm. Both rules apply at the same time: a 380 mm by 380 mm opening is too small.
  • Window wells: at least 550 mm of clear space in front of the window; steps or a ladder where the well is deeper than 1,000 mm; a cover that opens from inside without tools or keys.
  • Where it applies: every floor level with a bedroom needs at least one egress window, unless a door on that level leads directly outside (OBC 9.9.10).

Full explanation, window types and inspection tips: Egress window requirements in Ontario (2026).

Which window type to choose

Casement windows swing fully open, so almost the whole frame becomes clear opening. Sliders only open half their width, and awning or hopper windows are often blocked by their own sash. If you are close to the limit, choose a casement.

Questions people ask

What size does an egress window need to be in Ontario?

At least 0.35 m² (about 545 square inches) of unobstructed opening, with no dimension smaller than 380 mm (about 15 inches), measured with the window fully open.

Does a basement bedroom need an egress window?

Yes, unless that floor level has a door that leads directly outside. Every floor level containing a bedroom needs a way out.

How big does the window well need to be?

There must be at least 550 mm of clear space in front of the window, and a well deeper than 1,000 mm needs steps or a ladder. Any cover must open from inside without tools or keys.

Is this checker a code approval?

No. It is a planning tool. Your building department and inspector make the final call.

Related guides on BuildersOntario

Egress window requirements OntarioThe full rules, window types and inspection tipsLegal basement apartment requirementsEgress, ceiling height, fire separation and moreWindow replacement cost calculatorPrice new or replacement windowsBuilding permit drawings in OntarioWhat the township needs to see

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Updated November 2026. A planning tool based on the Ontario Building Code egress rules (9.9.10); the building department makes the final decision.