Toilet Paper Calculator

Using the toilet paper calculator

The calculator answers one of two questions. Pick How much toilet paper you need to get a number of rolls for the dates you enter, or How long will your toilet paper last to turn the rolls you have into a number of days.

• Start and end date (first mode): the span you want to cover. If you leave them empty the tool assumes today until tomorrow.
• Stock quantity (second mode): the number of rolls on your shelf.
• Sheets per roll: printed on the pack. It differs between brands and between standard, double and mega rolls, so check it instead of guessing. The minimum accepted is 50.
• Persons in household, daily toilet visits per person, wipes per visit and sheets per wipe: your own habits. The defaults of 3 visits, 3 wipes and 2 sheets are rough averages and are easy to change.

In the first mode the answer is a whole number of rolls, always rounded up so you do not run short. In the second mode the answer is a number of days, with the same span expressed in weeks, months and years where it is long enough to make sense.

Formulas and assumptions

Everything starts from how many sheets the household uses in a day.

sheets per day = persons × visits × wipes × sheets per wipe

rolls needed = ⌈ days × sheets per day ÷ sheets per roll ⌉

days of stock = ⌈ rolls × sheets per roll ÷ sheets per day ⌉

The brackets mean rounding up to the next whole number. The number of days between two dates is the end date minus the start date, so 1 January to 15 January is 14 days. When converting a span of days, weeks use 7 days, months 30.5 days and years 365 days.

Example 1: four people, 3 visits each, 3 wipes per visit and 2 sheets per wipe use 4 × 3 × 3 × 2 = 72 sheets a day. Over the 14 days from 1 to 15 January that is 1,008 sheets. With 300 sheets per roll, 1,008 ÷ 300 = 3.36, so you need 4 rolls.

Example 2: the same household has 12 rolls of 300 sheets, which is 3,600 sheets. At 72 sheets a day the stock lasts 3,600 ÷ 72 = 50 days, or about 7.14 weeks.

Example 3: a household of five on the same habits uses 90 sheets a day. For 14 days on 250-sheet rolls the need is 1,260 ÷ 250 = 5.04 rolls. Because a fraction of a roll cannot be bought, the answer is 6 rolls.

Limits of the estimate

The calculator treats every day alike and every person as using the same amount. Guests, children, illness, travel and different sheet counts on different brands all shift the real figure. If you buy rolls of more than one size, work out the sheets in each pack first and add them up, or enter an average.

It also ignores other uses of toilet paper in the house, such as tissues for noses or cleaning. A safety margin of a roll or two for each month is cheap insurance.

Why people stockpile toilet paper

Toilet paper is bulky, cheap and used by everyone, which makes an empty shelf look alarming. When news of lockdowns spread in early 2020, many shoppers bought more than they needed at once, and shelves in several countries went bare for weeks. Demand from households also rose because people were at home instead of using workplace and public restrooms, and the products made for those commercial buyers could not simply be redirected to supermarkets.

A calculator like this one helps turn a vague fear into a number. Example 2 above shows that 12 rolls already cover a four-person household for 50 days, so a trolley of 40 rolls mostly leaves less for your neighbors.

If you run out

A handful of substitutes exist, and they are not all equally kind to your plumbing.

• Bidet or handheld sprayer: uses water instead of paper and cuts consumption sharply. Attachments fit most toilets.
• Reusable cloth wipes: washed in hot water after use. Keep them in a closed container and wash them separately.
• Tissues or paper towels: fine to use, but put them in the trash. They do not break up in water as toilet paper does and can block pipes.
• Wet wipes: even those labeled flushable are a common cause of blockages. Bin them as well.

For more everyday planning tools, see the percentage calculator for working out how much of a stock you have used, or browse the other calculators category.