How do I convert square feet to square metres?

Multiply square feet by 0.09290304 to get square metres, or multiply square metres by 10.7639 to go the other way. For example a 200 ft² bedroom is 200 × 0.09290304 = 18.58 m², and a 25 m² studio is 25 × 10.7639 = 269 ft². This tool shows both numbers at once for every total, so you never have to do the multiply by hand or trust a rounded-off figure.

How do I add up the square footage of several rooms?

Add one row per room, type its length and width, and set the quantity if you have several identical spaces — say 3 bedrooms that are each 10 × 10 ft. The tool computes each room (length × width × quantity) and adds every row into a grand total. A 15×12 living room (180 ft²) plus a 13×11 bedroom (143 ft²) gives 323 ft² total, shown in m² alongside.

How much waste should I add when buying flooring?

A common rule is 10% extra for straight-lay vinyl or laminate, and 15% for diagonal or herringbone patterns where cuts waste more. If your room is 200 ft² and you add 10%, you buy for 220 ft². Put that percentage in the waste field and the tool shows the padded area separately, so you order enough to cover offcuts, mistakes and a few spare planks for later repairs.

How do I handle an L-shaped or irregular room?

Split it into rectangles. An L-shaped room is two rectangles: measure each part as its own row and the totals add up correctly. For a 12×10 ft main area plus a 6×4 ft alcove, enter two rows (120 ft² and 24 ft²) for 144 ft². For a triangle, take half of base × height and enter the result as a one-off. The row total always reflects the sum of whatever rectangles you list.

What if I mixed up feet and metres in my measurements?

Pick one unit system with the toggle and enter every room in that unit — do not mix feet and metres in the same list. If you measured one room in metres and the rest in feet, convert the odd one first (metres × 3.281 = feet) and type the converted value. The tool labels each length field with the active unit (ft or m) so you can double-check before reading the total.

Is square footage the same as the floor area I pay rent on?

Usually it is the usable floor area inside the walls, but leases and listings vary — some include closets, hallways and a share of common space, others quote only the room interiors. Measure wall to wall for each room to get the real usable area, then compare it to the figure on your lease. A gap of more than a few percent is worth asking your landlord or agent about.

Measure a whole apartment before signing a lease

You are deciding between two flats and want to know which one actually gives you more usable space, not just what the listing claims. Walk each room, type length × width into a row, and read the total in both square feet and square metres. Compare that number to the figure on the lease — if the real usable area is 8% smaller than advertised, you have a concrete point to negotiate the rent.

Budget a flooring or carpet order with waste built in

You are re-flooring the ground floor and the supplier prices by the square foot. Add a row for every room, set the waste field to 10% for straight planks (15% for herringbone), and the tool shows the padded area you actually need to buy. Drop in the price per square foot and you have a materials cost you can take to two suppliers and compare on the same basis.

Convert a metric floor plan to square feet for a US contractor

Your architect drew the plan in metres but the contractor quotes in square feet. Enter each room in metric, and the tool shows the grand total in ft² alongside — no separate converter, no rounding surprises. Copy the summary into your email so everyone is working from the same square-foot number.

Size a paint, tile or concrete order from one area number

Most material calculators start from "how many square feet?". Get a clean, accurate total here first — every room summed, waste optional — then carry it into a paint, tile or concrete estimate. One measured number feeds the whole project instead of re-measuring for each trade.

Square Footage Calculator — Multi-Room Area in ft² and m²

Add every room, get one total in ft² and m² at once — waste % + cost — browser-only

Runs locally
Category Calculator
Best for Getting a realistic range before a purchase, plan, workout, or schedule decision.

Add one row per room (name, length, width, quantity). The tool multiplies each room out, sums the whole space, and shows the total in square feet AND square metres at once. Add a waste % if you are buying flooring (10% covers offcuts), set a price per unit area for a quick cost. Switch units anytime — the number converts exactly.

Units

RoomLength (ft)Width (ft)QtyArea

180.00

143.00

100.00

Waste / overage (%)Add ~10% for flooring offcutsCurrencyPrice per unit area

/ ft²

Total area

39.30 m²

423.00 ft²

What this tool does

Free square footage calculator for measuring a whole home, an apartment or a single room and pricing the work. List each room as a row — name, length, width and how many identical rooms there are — and the tool multiplies every space out and sums the grand total. The number shows up in square feet AND square metres simultaneously (1 ft² = 0.09290304 m²), so you can read a US listing in m² or convert a metric floor plan to ft² without a second tool. Add a waste or overage percentage when you are buying flooring — ten percent covers offcuts and breakage — and set a price per square foot or per square metre for a quick materials cost in any currency. Switch between imperial feet and metric metres at any time; the totals convert exactly. Everything runs in your browser, with one-click copy and a shareable URL that reopens your exact room list. No sign-up, no upload, 100% client-side.

Tool details

Input: Text + Numbers; The page exposes text boxes, numeric controls, file pickers, or structured inputs depending on the tool.
Output: Live result + Copy; The result area focuses on usable output, with copy, download, or preview actions when supported.
Privacy: Browser-side processing; The main tool logic does not call an external API, so inputs normally stay in the current tab.
Save / share: Shareable URL state; Key settings are encoded in the URL so another person can reopen the same setup.
Performance budget: Initial JS <= 9 KB; No WASM budget is declared, keeping the tool quick to open on mobile.
Best fit: Calculator · Designer; Category and role tags drive related tools, internal links, and quick fit checks.

How to use

1. Input

Paste or drop your content into the tool panel.
2. Process

Click the button. All processing is local in your browser.
3. Copy / Download

Copy the result or download to disk in one click.

How Square Footage Calculator fits into your work

Use it for fast estimates, comparisons, and planning numbers before you make the final call.

Calculation jobs

Getting a realistic range before a purchase, plan, workout, or schedule decision.
Comparing scenarios by changing one input at a time.
Turning rough assumptions into a number you can discuss.

Calculation checks

Double-check units, dates, rates, and rounding assumptions.
Treat health, finance, tax, and legal outputs as planning aids, not professional advice.
Save the inputs that produced an important result so you can reproduce it later.

Good next steps

These links move the current task into a more complete workflow.

Real-world use cases

Measure a whole apartment before signing a lease
You are deciding between two flats and want to know which one actually gives you more usable space, not just what the listing claims. Walk each room, type length × width into a row, and read the total in both square feet and square metres. Compare that number to the figure on the lease — if the real usable area is 8% smaller than advertised, you have a concrete point to negotiate the rent.
Budget a flooring or carpet order with waste built in
You are re-flooring the ground floor and the supplier prices by the square foot. Add a row for every room, set the waste field to 10% for straight planks (15% for herringbone), and the tool shows the padded area you actually need to buy. Drop in the price per square foot and you have a materials cost you can take to two suppliers and compare on the same basis.
Convert a metric floor plan to square feet for a US contractor
Your architect drew the plan in metres but the contractor quotes in square feet. Enter each room in metric, and the tool shows the grand total in ft² alongside — no separate converter, no rounding surprises. Copy the summary into your email so everyone is working from the same square-foot number.
Size a paint, tile or concrete order from one area number
Most material calculators start from "how many square feet?". Get a clean, accurate total here first — every room summed, waste optional — then carry it into a paint, tile or concrete estimate. One measured number feeds the whole project instead of re-measuring for each trade.

Common pitfalls

Mixing feet and metres in the same list. The tool sums everything in one active unit, so a room typed in metres while the others are in feet will be off by a factor of ten in area. Pick a unit first and convert any odd measurement before entering it.
Forgetting to add waste before buying flooring. The raw area is the bare floor; offcuts, breakage and pattern matching mean you need 10-15% more material. Order exactly the measured area and you will run short mid-job and have to chase a matching dye lot.
Treating an L-shaped or irregular room as one rectangle. Multiplying the longest length by the widest width overcounts the notch you do not have. Split irregular spaces into separate rectangle rows so the total reflects the real floor.

Privacy

Every calculation — each room's area, the running total, the ft²/m² conversion, the waste padding and the cost — is plain JavaScript running in your browser tab. No room name, dimension or price ever leaves the page, and nothing is logged. The one caveat: the shareable URL encodes your room list and units in the query string, so a "share link" pasted into chat records those dimensions in the recipient server's access log. For a confidential floor plan, use the copy button and paste the text instead of sharing the URL.

FAQ

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Square Footage Calculator — Multi-Room Area in ft² and m²

What this tool does

Tool details

How to use

1. Input

2. Process

3. Copy / Download

How Square Footage Calculator fits into your work

Calculation jobs

Calculation checks

Good next steps

Real-world use cases

Measure a whole apartment before signing a lease

Budget a flooring or carpet order with waste built in

Convert a metric floor plan to square feet for a US contractor

Size a paint, tile or concrete order from one area number

Common pitfalls

Privacy

FAQ

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