Calculate square footage for a complete project

Use this square footage calculator to combine the area of multiple rooms or shapes into one project total. You can account for openings, add a waste allowance and estimate cost from a price per square unit.

How to use the calculator

1. Add each room or separate area in the project.
2. Choose the relevant shape and enter its measurements.
3. Add any openings or excluded areas that should not be covered.
4. Enter a waste allowance appropriate for the material and layout.
5. Add a price per square unit when you want a cost estimate.

Keep all measurements in consistent units. For irregular areas, split the space into simpler shapes, calculate each part and add the results together.

How square footage is calculated

The calculator first totals the area of the rooms or shapes entered. Excluded openings are subtracted to produce the net project area.

Net area = total measured area − excluded openings

When a waste allowance is entered, the calculator increases the net area:

Billable area = net area × (1 + waste percentage / 100)

An estimated cost can then be calculated from the billable area and the entered price per square unit:

Estimated cost = billable area × price per square unit

Square footage example

Suppose one rectangular room measures 12 ft by 10 ft and another measures 10 ft by 8 ft. Their combined area is 200 sq ft. After subtracting a 20 sq ft excluded area, the net project area is 180 sq ft.

Adding a 10% waste allowance gives a billable area of 198 sq ft. At $3 per sq ft, the estimated cost is $594. Actual material orders may need to be rounded to full packs, boards, rolls or containers.

Measuring tips

• Measure from the finished edges of the area that will be covered.
• Break L-shaped or irregular spaces into simple sections.
• Measure each room separately instead of relying on a whole-building estimate.
• Check whether doors, windows, cabinets or permanent fixtures should be excluded.
• Confirm whether the supplier prices material by square foot, square metre, square yard, pack or another unit.
• Recheck measurements before ordering materials or preparing a quote.

Choosing a waste allowance

Waste covers cutting, offcuts, breakage, pattern matching and unusable material. The right allowance depends on the product, room shape, installation method and required pattern.

Simple layouts may need less extra material than diagonal, patterned or highly irregular installations. Always check the manufacturer's installation guidance and pack coverage before placing an order.

Square feet and other area units

Area is expressed in square units. A measurement in feet produces square feet, while a measurement in metres produces square metres. One square yard equals 9 square feet, and one square metre is approximately 10.764 square feet.

Do not mix linear units within the same area calculation unless they have first been converted to a consistent unit.

Limits of the estimate

This result is a planning estimate. Real material requirements can vary because of pack sizes, roll widths, coverage rates, pattern repeats, installation standards and site conditions. Labour, delivery, taxes and minimum order quantities may also affect the final quote.

Use the Tile & Flooring Calculator for piece and box planning, the Paint Calculator for coating coverage, and the Roofing Calculator for roof-specific material estimates.

Frequently asked questions

Can I calculate square footage for multiple rooms?

Yes. Calculate each room or section separately and add the areas to obtain the total project area.

Should I subtract doors, windows or cabinets?

Subtract only areas that will not receive the material. Whether an opening should be excluded depends on the project and how the product is installed.

Why add waste to square footage?

Cutting, breakage, pattern alignment and irregular edges can require more material than the measured net area. A waste allowance adds this contingency to the estimate.

Does square footage tell me how many packs to buy?

Not by itself. Divide the required area by the verified coverage per pack and round up to full packs. Check the manufacturer's stated coverage because nominal dimensions and usable coverage may differ.