Grocery Price Comparator — Unit Price & Best-Deal Calculator

What is unit price?

A unit priceis the cost of one standardised unit of a product — per gram, per 100 grams, per kilogram, per millilitre, per litre, or per piece. It strips away packaging size so you can compare two products that come in different quantities. Without it, “₹120 for 500g” and “₹420 for 2kg” are impossible to compare at a glance; with it, you can immediately see that one is ₹240/kg and the other is ₹210/kg — the bulk pack is roughly 12.5% cheaper per kg.

Unit pricing is so important that several countries legally require supermarkets to display it on shelf tickets: the EU mandates it for most pre-packaged goods, the UK has required it since 1998, Australia since 2009, and many US states (notably California, New York, and Massachusetts) require it for grocery and drug stores. The point is the same everywhere — let shoppers compare like-for-like across pack sizes.

The formula

Unit price is just division:

unit price = total price ÷ (quantity × conversion factor)

The conversion factor only matters when the pack quantity is in a different unit from the one you want to compare in. For example, to express a 2kg pack as “per 100g”, the conversion factor is 1000 ÷ 100 = 10, so a ₹420 / 2kg pack costs 420 ÷ (2 × 10) = ₹21 per 100g.

Worked examples

How to read a supermarket shelf label

Modern shelf labels usually print two numbers, one big and one small. The big one is the sticker price — what you pay at the till. The small one (often in the corner, sometimes faint and hard to read) is the unit price. That smaller number is the one to compare across products. A few tips:

• Different units on different shelves trip you up.A 200g jar of peanut butter may show “per 100g”; a 1kg tub right next to it may show “per kg”. Convert in your head (or paste into the calculator above) before comparing.
• Pre-packed fresh produce is often priced per kg even when sold by the punnet — sanity-check against the loose price next to it.
• Multi-buy offers(“3 for ₹250”) sometimes recalculate the unit price for the offer, sometimes don't. Always re-derive from the deal price.
• Discounted items may keep the original unit price on the label; the new sale unit price is often printed separately on a yellow tag.

Common unit-pricing traps

• Bulk isn't always cheaper. Roughly 20–25% of bulk packs are actually more expensive per unit than their smaller siblings — usually on heavily-promoted items where the small pack is the “loss leader”. Always check.
• Shrinkflation.When a brand drops from 200g to 180g but keeps the same sticker price, the unit price quietly jumps 11%. Compare today's unit price to the one you remember from last quarter.
• Different forms. Concentrated juice at ₹400/L looks expensive vs ready-to-drink at ₹150/L until you realise the concentrate makes 4× the volume.
• Dehydrated vs fresh.Dried herbs are ~10× more concentrated than fresh — the unit prices aren't comparable without adjusting for that.
• Delivery and minimum-order fees.Online grocers' unit prices don't include shipping. If a 1kg pack only beats a competitor by ₹4/kg but costs ₹60 in delivery you've lost the saving on anything under a 15kg order.

Per 100g vs per kg — which should you use?

Both are correct; pick whichever scales to the size of pack you usually buy. Rule of thumb:

• Per 100g / per 100ml — best for snacks, spices, sauces, anything bought in packs under 1kg. Numbers stay readable (₹4.20/100g feels more intuitive than ₹42/kg).
• Per kg / per litre — best for staples (rice, flour, oil, milk, detergent) bought in 1kg+ packs.
• Per piece — eggs, fruit, soap bars, tea bags. Ignore weight entirely.
• Per serving— useful for breakfast cereal, ready meals, energy bars. Toggle “per serving” in the calculator above and add a servings-per-pack count.

The calculator above auto-picks a sensible unit for you (per 100g for weight, per 100ml for volume, per piece for count) and shows all the conversions side by side so you don't have to guess.