Square Footage Calculator for Rooms, Floors, and Projects
Enter the length and width of a room, wall, floor, yard, or project area. Use the unit switch if you want metric inputs and results.
Last updated: July 2026
Buying and sizing notes
- Round up when buying materials sold in full pieces, rolls, boxes, bags, or bundles.
- For rooms with closets, alcoves, or jogs, measure each section separately for better accuracy.
Square footage measurement tips
Square footage searches are usually simple, but mistakes happen when rooms have closets, jogs, alcoves, stairs, or multiple rectangles. Use this calculator as the base measurement, then round for the material you are buying.
Break up odd shapes
For L-shaped rooms, closets, or floor plans, calculate each rectangle separately and add them together.
Keep units consistent
Do not multiply feet by inches. Convert measurements first, or use the unit switch where available.
Add overage for materials
Flooring, tile, roofing, paint, and other materials usually need waste or coverage rounding beyond pure square footage.
Use plans carefully
Floor plan square footage is only as accurate as the scale and dimensions shown. Field measurements are better before buying materials.
How to use this estimate
What this includes
- Length
- width
- optional overage
- square feet and square meters
What it does not include
- Irregular curves
- rooms measured from plans without scale verification
- waste rules for specific products
Common mistakes
- Forgetting closets or alcoves
- Measuring only one section of an irregular room
- Multiplying inches as if they were feet
- Not rounding up for full boxes, rolls, sheets, or bags
Quick questions
How do I calculate square footage?
Measure length and width in the same unit, multiply length by width, then add any overage needed for the material or project.
How do I calculate square footage for an odd-shaped room?
Break the room into smaller rectangles, calculate each area separately, then add the pieces together.
Should I include closets?
Yes, include closets, alcoves, and other connected floor areas if you need material for those spaces.
Related guide
Use the guide with this calculator when you need more context before buying materials or comparing options.
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