Tile Calculator

Calculate how many tiles and full boxes to buy for floors, walls, showers, or several areas. Use the coverage printed on the carton for the safest order, then add realistic waste, cost, trim, and optional repair stock.

Reviewed and updated July 10, 2026

Use it when you want to know

How many full boxes to orderTurn one or more measured areas into a rounded, buyable quantity.
How much waste to allowUse practical defaults for straight, offset, diagonal, herringbone, and irregular layouts.
What the final order coversSee purchased coverage, planned surplus, tile pieces, trim, and optional cost.

Calculator

How many tiles and boxes do you need?

Add each tiled area, enter the real coverage printed on the carton, and choose a layout. The result separates measured area, waste, box rounding, and repair stock.

Measurement systemValues convert when you switch.

USMetric

Project area

Add floors, walls, shower surfaces, or other rectangles using the same tile.

How will you enter the tiled area?

Add areasI know the total

Area dimension unit

Openings and no-tile areasOptional

Subtract only large windows, tubs, cabinets, or other areas that will not receive tile.

Tile product

Carton coverage is the safest input for a real purchase order.

What information do you have?

Coverage per boxIndividual tiles

Coverage per box or sheet carton

sq ft

Copy the exact coverage from the carton or product listing.Tiles per boxOptional. Adds estimated and purchased piece counts.

Use this mode for hexagon, penny, mosaic-sheet, mixed-size, handmade, and irregular tile.

Cost and edge trimOptional

CurrencyPrice per box

Exposed edge length

Trim piece length

Price per trim piece

Layout and waste

Use the preset as a starting point, then adjust it for the real job.

Tile layoutThese are planning defaults, not guarantees.Base waste allowance

Effective allowance: 10%.

Many corners, niches, or first-time DIYAdd 5 percentage points for extra cuts and mistakes.Intentional repair boxesKept beyond the installation order. The result also shows a one-extra-box comparison.

Guide

How do you calculate how much tile to buy?

A practical tile estimate uses measured area, a realistic cutting allowance, and the actual packaging you can buy. Keeping those numbers separate makes shortages and overbuying easier to spot.

Should you use box coverage or tile dimensions?

Use the square-foot or square-meter coverage printed on the carton whenever possible. It already reflects the product configuration and is safer for hexagons, mosaics, handmade tile, and mixed-size patterns.

Individual length and width are useful when tiles are sold loose or when you want a piece estimate. That result is still approximate because nominal dimensions, cut reuse, and the exact starting position change what happens at the room edges.

Box-order formulaboxes = ceil((net area × (1 + waste %)) ÷ box coverage)

For 120 sq ft with 10% waste, plan for 132 sq ft. A 15.5 sq ft carton gives 132 ÷ 15.5 = 8.52, so buy 9 boxes. Those boxes cover 139.5 sq ft, leaving 7.5 sq ft beyond the planned allowance.

How much extra tile should you buy?

Ten percent is a useful starting point for a simple straight layout. Angled cuts, herringbone, niches, many corners, fragile material, culling visibly different pieces, or first-time DIY work can need more. The calculator's presets are planning aids; manufacturer guidance and an experienced installer's layout take priority.

Do grout lines change the tile count?

A grout joint slightly enlarges the module occupied by a rectangular tile, so it can change a piece estimate. It does not increase or decrease the coverage stated on a carton. Grout width should also account for real tile-size variation rather than being chosen by calculator alone. Review the Tile Council of North America grout-joint guidance.

How do you measure floors, walls, and showers?

Split the project into rectangles and add them. Treat every shower wall as a separate rectangle. Subtract large windows, tubs, and fixed no-tile zones, but keep small outlets, drains, and pipe penetrations in the area because they create cuts.

Why do shade and caliber matter?

Tile batches can vary in color and facial size. The TCNA ceramic tile guidance recommends matching caliber and shade across boxes and mixing pieces from multiple cartons during installation.

How do you calculate bullnose or edge trim?

Measure exposed wall ends, outside corners, curb edges, or other finished edges. Divide the total length by one trim-piece length and round up. Confirm whether corner pieces, miters, or factory-finished edges change the order.

What should you calculate next?

Use the grout calculator after choosing the tile and joint. For outlets, adhesive, caulk, and kitchen-specific trim, use the backsplash tile calculator.

FAQ

Tile calculator questions

How many tiles do I need for 100 square feet?

For a simple straight layout, start with about 110 square feet of tile coverage after a 10% allowance. The number of tiles or boxes depends on the coverage printed on the carton. For example, boxes covering 15.5 square feet require 8 boxes because 110 divided by 15.5 must be rounded up.

How much extra tile should I buy?

About 10% is a common planning allowance for a simple straight layout. Running bond may need around 12%, diagonal work around 15%, and herringbone or difficult patterns around 18% to 20%. Room shape, tile quality, installer skill, and manufacturer guidance can justify a different amount.

Do grout lines change how many tiles I need?

Grout joints slightly change the space occupied by each rectangular tile, especially with small tiles or wide joints. They do not change the square footage printed on a carton. Use carton coverage for ordering boxes and grout-aware dimensions only for an estimated individual piece count.

How do I calculate how many boxes of tile to buy?

Multiply the tiled area by one plus the waste percentage, divide by the carton coverage, and round up. A 120 square foot project with 10% waste needs 132 square feet. At 15.5 square feet per box, that is 8.52 boxes, so buy 9.

Should I subtract doors, cabinets, drains, or other openings?

Subtract large areas that definitely will not receive tile, such as a full doorway, tub footprint, large window, or fixed cabinet run. Do not bother subtracting tiny penetrations, outlets, or drains because they create cuts and usually do not reduce the order meaningfully.

How should I calculate hexagon, penny, or mosaic tile?

Use the manufacturer's square-foot or square-meter coverage per box or sheet. Do not treat a hexagon as a rectangle or rely on nominal mosaic dimensions; those shortcuts can materially misstate coverage.

Should I keep an extra box of tile for repairs?

Keeping one unopened matching box can be useful when the tile may be discontinued or difficult to match later. Check the return policy and storage space first. The calculator separates installation boxes from intentional repair stock so the recommendation stays transparent.

Can I use this tile calculator for walls and showers?

Yes. Add each wall as a separate rectangle and subtract large windows or no-tile zones. For a kitchen backsplash with outlets, adhesive, caulk, and detailed trim planning, use the dedicated backsplash tile calculator.