Cost per Use: How to Compare Razors, Pods and Tablets

A pack of 8 razor cartridges costs $21.99. A bag of 12 disposable razors costs $9.99. Per item, the disposables are obviously cheaper — but they don’t last as long. Say you get about 7 shaves from a cartridge and 3 from a disposable (count your own; it varies a lot).

Here the disposables are about 29% cheaper per shave. If your cartridges lasted 10 shaves instead, they would cost $21.99 ÷ 80 ≈ $0.27 per shave and win. The number of uses decides it.

A box of 60 dishwasher tablets costs $11.99. A bottle of dishwasher gel costs $5.49 and says it is good for 60 loads.

1. Tablets: $11.99 ÷ 60 loads ≈ $0.20 per load.
2. Gel: $5.49 ÷ 60 loads ≈ $0.09 per load.
3. The gel is about 54% cheaper per load — if you dose it as the label says.
4. If you pour a double dose, the gel gives 30 loads and costs about $0.18 per load. The gap almost closes.

Try your own numbers below: enter the number of uses as the size, with “uses” as the unit.

cost per use = price ÷ number of uses

For products sold by count, the number of uses is items × uses per item. For products sold by volume or weight, it is the total amount ÷ the amount you use each time. Either way, it is your real usage that matters, not the box’s promise.

Labels give a best case: “up to 64 loads”, “lasts up to a month”. The simplest way to find your own number is to mark the date when you open a pack and when it runs out, or tally uses on the box. Do it once for each product you buy often and write it in your price book.

• Laundry: do you use the line on the cap, or fill above it? Large loads may take two pods.
• Coffee: how many grams per cup do you really use? See coffee cost per cup.
• Razors: how many shaves before it pulls?
• Paper towels: how many sheets per spill?

Some products need a handle, a machine or a dispenser. Spread that cost over the uses you expect to get from it. A $100 coffee machine used for 730 cups over two years adds about 14 cents per cup; a razor handle used for 400 shaves adds a few cents per shave. Usually it is small — but when comparing pods with a machine against beans with a filter, it can matter.

1. Find out how many uses you really get — not the label’s “up to”.
2. Divide the price by the number of uses.
3. Add a share of any one-time equipment cost if the options differ.
4. Compare products of the same kind first; then across kinds if you’re open to switching.

For detergent the cost per load calculator is set up already; for anything else counted by item, use the cost per item calculator.

A tub of 81 laundry pods costs $19.99. A bottle of liquid detergent rated for 64 loads costs $12.99. How you dose changes the answer:

At the labeled dose the liquid is cheaper; if you habitually overfill the cap, the pods win. The laundry detergent calculator compares the labeled counts — adjust the number of loads to your real usage.

• Using the box’s “up to” number instead of your real count.
• Comparing a multi-use item with a single-use one per item instead of per use.
• Ignoring a big one-time cost, such as a machine, when comparing two systems.