---
title: "Shrinkflation Checker: Real Unit Price Change | Pebble Pouch"
description: "Did the pack shrink? Compare the old size and price with the new ones to see the real change in unit price, even when the shelf price hasn't moved."
url: https://pebblepouch.shop/shrinkflation-checker/
---

# Shrinkflation checker

Same price, smaller bar? Enter the old pack and the new one to see how much more you really pay for every gram or millilitre.

## Size and price, together

Shrinkflation is when a product gets smaller while its price stays the same, or falls by less than the size did. The shelf price hides it; the unit price shows it. Official statisticians look at it the same way: the UK's Office for National Statistics adjusts for changes in a product's weight or volume when it measures inflation, so a smaller pack at the same price counts as a price rise.

Real change = (new price ÷ new size) ÷ (old price ÷ old size) − 1

In the example, a 200 g bar at £1.85 became a 180 g bar at £1.95. The shelf price went up 5.4%, but you get 10% less, so every gram costs 17.1% more.

### Finding the old size

Look for an old wrapper or receipt, a photo on your phone, or your online order history, which usually lists the pack size. Make sure it's the same product: a "new recipe" can change more than the size.

## Sources

- Office for National Statistics, [Shrinkflation: how many of our products are getting smaller?](https://www.ons.gov.uk/economy/inflationandpriceindices/articles/theimpactofshrinkflationoncpihuk/howmanyofourproductsaregettingsmaller) (21 January 2019): how size changes are adjusted for in consumer price statistics.
- NIST, [Guide to the SI, Appendix B.9](https://www.nist.gov/pml/special-publication-811/nist-guide-si-appendix-b-conversion-factors/nist-guide-si-appendix-b9): unit conversion factors.

## Questions

**Why does a small size cut make such a big difference?**

The price is spread over less. A pack that is 10% smaller at the same price costs 11.1% more per gram, because 1 ÷ 0.9 = 1.111.

**Can I compare a pack in grams with one in ounces?**

Yes. Pick each pack's own unit and the checker converts them. It can't compare a weight with a volume.

**What if the new pack is better value?**

The checker says so. A pack can shrink and still be better value if its price fell by more than its size.