When you reach for this
- You are at the shelf, the same product comes in three pack sizes, and the unit price label is missing or unreadable.
- You are comparing online listings where every seller uses a different size or bundle.
- You want to know whether the family size is genuinely cheaper or only looks that way.
- A promotion offers two for one or half price on the second item and you want the real per-unit figure.
- You are buying supplies for a household or an office and need a comparison you can paste into a record.
How the unit price is worked out
One step: price divided by amount. Amounts are always entered in the smallest unit, so every product already shares the same denominator and the results can be ranked directly.
| Step | How it is worked out | Example |
|---|---|---|
| Convert to the smallest unit | You do it, 1 kg is 1000 g | A 1 kg bag is entered as 1000 |
| Bundles | Bundle price, and the total amount in the bundle | A three-pack of 400 g is entered as 1200 |
| Price per unit | Price ÷ amount | 159 ÷ 1000 = 0.159 per g |
Why there is no unit to choose
Most price comparison tools let you pick between grams and kilos. This one deliberately does not, and asks for the smallest unit instead. There are two reasons:
- Converting is faster than choosing. Working out that 1 kg is 1000 g takes less time at the shelf than operating a dropdown.
- A wrong unit goes unnoticed. Pick grams where you meant kilos and the unit price still looks entirely normal, only the ranking is upside down. One field fewer is one mistake fewer.
The measure is chosen once for the whole comparison
It sets the unit for the amount field and the unit the results are written in. It applies to every product rather than to each one separately, because mixing weight with volume produces a ranking that means nothing. 100 g and 100 ml are not the same thing.
- Weight, in grams, for rice, flour, washing powder and anything sold by weight.
- Volume, in millilitres, for milk, drinks, shampoo and anything sold by volume.
- Count, in items, for tissues, batteries, masks and anything sold by the piece.
- Length, in centimetres, for cling film, foil, cable and anything sold by length.
The bigger pack is not automatically cheaper
Bulk usually wins on unit price, and there are three common exceptions:
- A small pack on promotion. A discounted small size often beats the large size at its normal price, and this is the case that flips the ranking most often.
- Bundle pricing. A three-pack is not always cheaper than three single items. Some bundles simply charge you for not having to choose.
- The same product in a different shop. Identical sizes can differ sharply between retailers, and entering them together makes that visible.
What the unit price does not tell you
This tool answers what each unit costs. The following sit outside the arithmetic and still decide what to buy:
- Whether you finish it before it spoils or expires. A pack you cannot use is not a saving.
- Whether you have somewhere to put it. A stockpile ties up cash and space together.
- How much leaves your account today. A low unit price with a high total still takes the cash now.
- Whether the products are genuinely comparable. Unit price compares numbers, not contents.
To see how much cash a stockpile keeps tied up at home, the household cash cycle calculator works out exactly that.
Using it on a phone in the aisle
This page is built for someone standing at the shelf holding a phone in one hand, so only two fields are required and everything else can be skipped.
- Pick the measure once. A single shopping trip rarely needs it changed again.
- Each product has two fields, price and amount, and the ranking appears once two are filled.
- There is no name field. Products are listed as product 1, product 2, matching the rows you filled.
- Adding a product puts the cursor straight into the new row's price field.
- Tapping a field you already filled selects it, so correcting a price takes no deleting.
- The ranking updates as you type, and the verdict stays pinned to the bottom of the screen.
What this tool deliberately does not do
- No price lookups. Prices are typed in. Fetching them needs a server to make the call, this site has no backend, and it will not gain one for this.
- No currency conversion. Rates move, and a stale built-in rate is worse than none. Enter one comparison in one currency.
- No memory. There are no accounts and no saving, so closing the tab means entering the products again. Copy or download the comparison to keep it.
Do the figures you enter leave the browser
No. The prices and amounts you enter are all computed in your browser, no request carries them anywhere, and nothing is written to browser storage — closing the tab is enough. The downloaded comparison is assembled on your own machine. See the privacy policy for the details.
Frequently asked questions
- Why is there no unit to choose, and why convert by hand?
- Because converting is both faster and safer than picking a unit. Working out that 1 kg is 1000 g takes less time at the shelf than operating a dropdown, and a wrongly chosen unit produces a unit price that looks entirely normal, so the mistake goes unnoticed. One field fewer is one mistake fewer, and that trade is deliberate.
- How do I enter a three-pack or a bulk box?
- Put the price of the whole bundle in the price field and the total amount in the amount field. A three-pack of 400 g is entered as 1200 with the bundle price. The unit price then reflects what you actually pay per gram.
- Why is there no currency to pick?
- Because the comparison is a ratio. As long as every product in one comparison is entered in the same currency, the ranking and the percentages are correct. This site has no region detection, and showing the wrong symbol misleads more than showing none, so amounts carry no symbol.
- How do I handle two for one or half price on the second item?
- Put what you actually pay in the price field and what you actually take home in the amount field. Two for one on a 500 g pack is the price of one with 1000 as the amount. The unit price then reflects what you really pay.
- Should I always buy the lowest unit price?
- Not always. Unit price answers what each unit costs, not whether you will use it all. Expiry dates, storage space and the larger amount leaving your account today are all outside the arithmetic. That is why the tool flags the case where the cheapest per unit is also the largest pack.