Unit price calculator for the supermarket aisle
Which pack is really cheaper?
Point your phone at two shelf tags. TwoTags reads the price and size off each one, shows you what it read, and tells you which pack costs less per 100g, per litre, per ounce or per item.
Try the sum here
This is the calculation the app does for you in the aisle. Enter each pack's price and size.
What it does
Two tags, one answer.
Read the price and size off each tag and see the cheaper pack, how much less it costs per unit, and the percentage.
Sizes that do not match.
6 x 330ml against 2 litres, 16 oz by weight against 500g, kilos against grams. All worked out on one unit, in metric or US measures.
Two prices on one tag.
If the reader finds a member price and a shelf price, both show up and you pick the one you will really pay.
The pack that got smaller.
Name a pack and the unlock compares it with your last saved reading of that product: on 5 March your reading was 500g, per unit it now costs 11.1% more.
A price book of your own.
Tap Bought this pack to keep the item, shop, price, size and date. The unlock draws the unit price over time for each item.
A card to send.
Both packs, the winner and the difference on one small image, ready for whoever does the other half of the shopping.
One price, once
Standard
No charge
- Compare two packs, by camera or typing
- Bought this pack and the Book
- Share cards and backup
- One banner in the Book, none on the compare
Unlock
$3.99 once
- Price history chart for each item
- A line when a pack gets smaller or dearer
- Up to six packs in one compare
- Add readings by hand, no banner
Questions
How do I work out which pack is cheaper?
Convert both pack sizes to the same unit, then divide each price by its total size and compare. TwoTags does this from the two tags.
Does it read every shelf tag correctly?
No. Tags vary and camera reads can be wrong, so TwoTags always shows what it read for you to check, and you can correct it or type the numbers.
Does it know which shop is cheapest?
No. It has no live prices. It works out unit prices from what you read or type, and keeps a history of your own readings.
Does it upload my photos or prices?
No. Tags are read on your phone, there is no account, and pictures and prices are kept out of analytics and crash reports. The standard version shows one ad banner in the Book.
What does the unlock cost?
A one-time $3.99 in the US and £2.99 in the UK, with no subscription. Comparing two packs, Bought this pack, the Book, sharing and backup do not need it.
Take it on your next shop
TwoTags for Android. No account, and your readings stay on your phone.