Rex says
The fast lane for the math you almost remember from school. Type the numbers, get the answer, move on with your day.
Try a scenario
Click to load — tweak from there.Inputs
Result
Total square footage
180.0
Main section area
180.0
Second section area
0.0
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One click, a permanent link with your numbers baked in.
How to use this
- 1Enter length (main section) (ft).
- 2Enter width (main section) (ft).
- 3Enter l-shaped room with second section?.
- 4Enter length (second section) (ft).
- 5Enter width (second section) (ft).
- 6Read your total square footage on the right — it updates as you type.
- 7Hit Share to keep the scenario or send it to someone.
About this calculator
Room square footage for a rectangular space is simply length multiplied by width. This calculator also handles an irregular L-shaped room by letting you add a second rectangular section and summing the two areas.
Worked example
Using the values the calculator loads with:
Inputs
- Length (main section): 12 ft
- Width (main section): 15 ft
- L-shaped room with second section?: No, simple rectangle
- Length (second section): 5 ft
- Width (second section): 4 ft
Results
- Total square footage: 180
- Main section area: 180
- Second section area: 0
What each field means
Inputs
- Length (main section) (ft)
- The length (main section) used in the calculation, measured in ft. Starts at 12 ft so you have a working example on load.
- Width (main section) (ft)
- The width (main section) used in the calculation, measured in ft. Starts at 15 ft so you have a working example on load.
- L-shaped room with second section?
- Pick the option that matches your situation — the maths changes per option. Choices: No, simple rectangle, Yes, add second section.
- Length (second section) (ft)
- The length (second section) used in the calculation, measured in ft. Starts at 5 ft so you have a working example on load.
- Width (second section) (ft)
- The width (second section) used in the calculation, measured in ft. Starts at 4 ft so you have a working example on load.
Results
- Total square footage
- Returned as a whole number and shown as the headline result. It recalculates instantly whenever you change an input, so you can compare scenarios without reloading.
- Main section area
- Returned as a whole number. It recalculates instantly whenever you change an input, so you can compare scenarios without reloading.
- Second section area
- Returned as a whole number. It recalculates instantly whenever you change an input, so you can compare scenarios without reloading.
FAQ
How many square feet is my room?
A room measuring 12 feet by 15 feet is 180 square feet (12 × 15).
How do I measure an L-shaped room?
Split it into two rectangles, measure each separately, calculate each area, and add them together — this calculator does that math for you when you enable the second section.
Should I measure wall-to-wall or floor-to-floor?
For most home projects like flooring and paint, measure wall-to-wall at floor level, which represents the actual usable floor area you'll be covering or painting around.
How do I convert square feet to square yards?
Divide square feet by 9 — a 180 sq ft room is 20 square yards, which matters for carpet since it's commonly priced and sold by the square yard.
Accuracy and limitations
- Results are rounded for display; the underlying calculation keeps full precision.
- Very large or very small inputs may hit floating-point limits in the browser.
- Inputs outside the accepted range are clamped rather than rejected.
Related tools
Cite this calculator
Writing about this topic? Grab a citation — every link helps keep these tools free.
RevenueLab. (2026). How Many Square Feet Is My Room?. Retrieved from https://www.revenuelab.fyi/toolbox/how-many-square-feet-is-my-room
<p>Source: <a href="https://www.revenuelab.fyi/toolbox/how-many-square-feet-is-my-room" target="_blank" rel="noopener">How Many Square Feet Is My Room? — RevenueLab</a> (2026).</p>
Source: [How Many Square Feet Is My Room? — RevenueLab](https://www.revenuelab.fyi/toolbox/how-many-square-feet-is-my-room) (2026).