Square Footage Calculator

Add up room dimensions from a floor plan to get per-room and total square footage, with square meters included.

How it works

Add a row for every room you want counted, enter its length and width in feet, and the tool multiplies the two for that room's area, then adds every row together for the total. It also converts the total to square meters, since some appraisal, mortgage, and international listing contexts want that figure too. The math itself is simple, the part that trips people up is deciding what to measure and where a room's boundary actually is.

Worked example: a living room measuring 12 feet by 10 feet is 120 square feet. Add an 8 by 6 foot nook off the same room and the pair totals 168 square feet, which converts to 15.61 square meters. Notice that's not simply adding two separately-rounded numbers, the tool sums the raw areas first and rounds only the total, so you don't lose fractions of a square foot to repeated rounding across a lot of rooms.

A few measuring conventions matter here. Interior square footage (the number most floor plans and real estate listings use) is measured wall to wall along the finished interior surface, not from the outside of the framing. Closets usually count if they're finished, heated space, unfinished basements, garages, and covered porches typically don't count toward livable square footage even though they're on the same set of plans. If a room isn't a clean rectangle, an L-shaped living and dining combo, say, split it into two rectangular rows in the tool and let it add the pieces.

FAQ

Does square footage include the walls themselves?

For standard livable-area square footage, no, you measure the interior finished space, wall to wall, not the wall thickness. Some construction and framing takeoffs instead measure to the outside of the studs, which will read a bit larger for the same room. Check which convention a given appraisal or listing is using before you compare two numbers.

How do I handle a room that isn't rectangular?

Break it into rectangles. An L-shaped room is two rectangles, a bay window alcove is a small rectangle (or a triangle you approximate as one) added to the main room. Add each piece as its own row in the tool and the total still comes out accurate, this is exactly how a drafter or appraiser would work it out by hand.

Do closets and hallways count toward total square footage?

Finished, heated closets and hallways generally count toward gross livable area in most appraisal standards, though conventions vary by region and by whether you're following a lender's guideline or a local listing standard. When in doubt, add them as their own rows so you can include or exclude them from your total as needed.

Why does my total not match the square footage on the listing?

Listings sometimes include or exclude finished basements, garages, or porches differently than you'd expect, and some are simply rounded or estimated rather than measured room by room. If you need a number you can defend, measure and add up the rooms yourself the way this tool does rather than relying on a single quoted figure.

For more on measuring rooms and reading square footage, see How Square Footage Is Calculated, How to Measure a Room and Sketch a Floor Plan, and Space Planning Basics for Beginners.