Period Products Cost Calculator

Background.

Pads and tampons are cheap one at a time, which is exactly why their yearly cost goes unnoticed. Twenty products at 35 cents each is $7 a period, an amount nobody budgets for; repeated through a year it becomes $91, and over ten years it is $910 at today's prices.

Reusable options — menstrual cups and discs, washable cloth pads, period underwear — swap that stream of small purchases for one larger payment. Whether the switch saves money comes down to three things: what you spend on disposables now, what the reusable kit costs, and how long it lasts before you replace it.

The comparison here puts both on a yearly footing. The disposable side is straight multiplication: products per cycle, times the price of each, times the number of cycles in a year. The reusable side spreads the purchase price evenly across its working life, so a $45 product expected to last three years counts as $15 a year. The headline figure is the gap between the two.

Cycles per year is the input people most often get wrong. A cycle runs from the first day of one period to the first day of the next, and at 28 days that gives about 13 periods a year, not 12. Shorter cycles mean more periods: at 24 days it is just over 15.

Several real costs sit outside the sum. Water, detergent and the energy used to wash or boil reusables are not counted, nor are spare items, a cup replaced early because the size was wrong, or price rises on disposables. Comfort, convenience and whether a particular reusable suits your body are questions a cost figure cannot answer.

What is period products cost calculator?

The annual saving is the difference between two yearly costs: what a year of single-use period products costs you, and the purchase price of a reusable alternative divided evenly over the years it lasts. A positive figure means the reusable is cheaper per year; a negative one means it costs more than the disposables it would replace. Everything is in dollars and counts purchase prices only.

How to use this calculator.

1. 01Count the pads, tampons or liners you get through in a typical period and enter that as products per cycle. If you would keep buying some for backup after switching, enter only the ones the reusable would replace.
2. 02Enter the cost of one product by dividing the pack price by the number in the pack — a 36-pack at $12.60 works out to $0.35 each.
3. 03Enter how many periods you have in a year: 365 divided by your cycle length in days, or simply the number you had last year if your cycle varies.
4. 04Enter the full upfront cost of the reusable kit — if you would need three pairs of period underwear to get through a cycle, enter the price of all three — and the number of years you expect it to last.
5. 05Read the annual saving, then check the two figures beneath it: the yearly disposable spend and the reusable's annualized cost that it was worked out from.

The formula.

Two yearly costs are computed and one is subtracted from the other. The disposable annual cost is D = n × p × c, where n is products per cycle, p the price of one product and c the number of cycles a year. The reusable annualized cost is R = U ÷ L, where U is the upfront price and L the expected life in years — a straight-line spread with no interest and no allowance for the money being paid at the start. The annual saving is S = D − R. Because D multiplies three inputs together, a 10% error in any one of them moves D by 10%, so the result is most sensitive to how many products you use and what you pay for each. The reusable's life matters most when it is short: halving a three-year life to eighteen months doubles R.

A worked example.

Frequently asked questions.

References& sources.

1. [1]U.S. Department of Energy. Energy Saver current 2026. Household energy guidance. Retrieved 2026-08-06.
2. [2]National Institute of Standards and Technology. NIST SI Guide, 2008 edition. Appendix B unit relationships. Retrieved 2026-08-06.
3. [3]OpenStax, Rice University. University Physics, 2016. Volume 1 mechanics and Volume 2 thermodynamics. Retrieved 2026-08-06.