Unit Price Comparison Calculator (which is cheaper?)
＋More features: unit price including shipping, and the free-shipping threshold
Compare with shipping included (for online shopping)
Compares the effective unit price with the shipping added to the price (leave shipping at 0 if there is none).
Almost at free shipping — should I add something?
When you are “X yen away from free shipping”, this tells you whether adding another item or paying the shipping leaves you out of pocket by less.
Enter the price and the amount (g, ml or number of pieces) and see which product is really the cheapest, compared by unit price. It also shows how many percent more expensive each of the others is. Handy for weighing up the large and small packs in a Japanese supermarket, or for comparing prices online. Prices are in Japanese yen.
How to use
- Choose the basis. Use “per 100” to compare by weight or volume, and “per 1” for things counted in pieces, such as eggs or boxes of tissues.
- Enter the price and the amount for each product (two are enough — product C can be left blank).
- As soon as two products are filled in, the unit prices and the cheapest product appear — no button needed.
How it is calculated
- Unit price = price ÷ amount × basis (the basis is 100 for “per 100 g”)
- Example: detergent A at 298 yen for 400 g → 298 ÷ 400 × 100 = 74.5 yen per 100 g. Detergent B at 198 yen for 250 g → 79.2 yen per 100 g. So A is about 6% cheaper.
- The “how much more expensive” figure is measured against the cheapest unit price.
Sources and assumptions
- This is an arithmetic calculation based on the price and the amount.
Assumptions and notes
- Use the same unit for every product you compare (grams with grams, milliliters with milliliters, pieces with pieces). Mixing g and ml gives a meaningless comparison.
- Also keep the prices consistent: either all tax-inclusive or all tax-exclusive.
- A low unit price is no bargain if you end up throwing part of it away. For anything with a use-by date, check that you can finish it.
Frequently asked questions
Is the large pack always cheaper?
Usually, but it is not rare for the smaller size to win once a sale or a coupon is applied. That is exactly why working out the unit price on the spot is the reliable way to decide.
What unit price counts as cheap?
Prices differ by category, so there is no single answer. The basic approach is to compare products on the same shelf. If the shelf label shows a unit price (for example “per 100 g”), that is useful too.
Can I compare a refill pack with the bottle?
Yes. Enter the price and the amount (ml) for the refill and for the bottle. Refills usually have the lower unit price, but a bottle in a bonus-size promotion can come out ahead.