Rex says
Everyday utility math — the kind you'd otherwise pull up four browser tabs for. I keep it to one clean answer.
Try a scenario
Click to load — tweak from there.Inputs
Result
Tile boxes to buy
5
Estimated tile cost
$175
Floor area
40
Area with waste
44.0
Psst — share this and help Rex grow
One click, a permanent link with your numbers baked in.
How to use this
- 1Enter room length (ft).
- 2Enter room width (ft).
- 3Enter waste factor (%).
- 4Enter coverage per box (sqft).
- 5Enter price per box ($).
- 6Read your tile boxes to buy on the right — it updates as you type.
- 7Hit Share to keep the scenario or send it to someone.
About this calculator
A 5x8 bathroom is one of the most common floor plans in North American homes, so this calculator starts with that 40-square-foot footprint and lets you adjust tile size, waste factor, and box coverage to get an accurate shopping list. It converts the floor area into the number of tile boxes you need to buy (always rounding up, since partial boxes aren't sold) and estimates total material cost so you know what to budget before heading to the store.
Worked example
Using the values the calculator loads with:
Inputs
- Room length: 8 ft
- Room width: 5 ft
- Waste factor: 10 %
- Coverage per box: 10 sqft
- Price per box: 35 $
Results
- Tile boxes to buy: 5
- Estimated tile cost: $175
- Floor area: 40
- Area with waste: 44
What each field means
Inputs
- Room length (ft)
- The room length used in the calculation, measured in ft. Starts at 8 ft so you have a working example on load.
- Room width (ft)
- The room width used in the calculation, measured in ft. Starts at 5 ft so you have a working example on load.
- Waste factor (%)
- The waste factor used in the calculation, measured in %. Starts at 10 % so you have a working example on load. Accepted range: 0–30 %.
- Coverage per box (sqft)
- The coverage per box used in the calculation, measured in sqft. Starts at 10 sqft so you have a working example on load.
- Price per box ($)
- The price per box used in the calculation, measured in $. Starts at 35 $ so you have a working example on load.
Results
- Tile boxes to buy
- 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.
- Estimated tile cost
- Returned as a money amount in US dollars. It recalculates instantly whenever you change an input, so you can compare scenarios without reloading.
- Floor area
- Returned as a whole number. It recalculates instantly whenever you change an input, so you can compare scenarios without reloading.
- Area with waste
- Returned as a decimal number. It recalculates instantly whenever you change an input, so you can compare scenarios without reloading.
FAQ
How much tile do I need for a 5x8 bathroom?
A 5x8 bathroom is 40 square feet; with a 10% waste factor you should buy enough tile to cover about 44 square feet, which usually means rounding up to the nearest full box.
Why round up to full boxes instead of buying exact tile count?
Tile is sold in sealed boxes and most retailers won't split them, plus keeping a spare box on hand is useful for future repairs after grout or a cracked tile.
Should I increase the waste factor for diagonal tile layouts?
Yes, diagonal patterns and rooms with lots of cuts around fixtures like the toilet and vanity often need 15-20% waste instead of the standard 10%.
Accuracy and limitations
- Estimates assume standard, average conditions — local rules, pricing, and materials vary.
- Results are rounded for readability; add a buffer before ordering, booking, or committing.
- Double-check anything with a real cost attached against a local quote.
Cite this calculator
Writing about this topic? Grab a citation — every link helps keep these tools free.
RevenueLab. (2026). 5x8 Bathroom Tile Calculator. Retrieved from https://www.revenuelab.fyi/toolbox/5x8-bathroom-tile-calculator
<p>Source: <a href="https://www.revenuelab.fyi/toolbox/5x8-bathroom-tile-calculator" target="_blank" rel="noopener">5x8 Bathroom Tile Calculator — RevenueLab</a> (2026).</p>
Source: [5x8 Bathroom Tile Calculator — RevenueLab](https://www.revenuelab.fyi/toolbox/5x8-bathroom-tile-calculator) (2026).