How much have your groceries really gone up? Working out your own grocery inflation
October 1, 2026
In the twelve months to August 2026, US grocery prices rose 2.2%, according to the Bureau of Labor Statistics’ “food at home” index. If your receipts feel like they say something else, they may well be right.
The official number prices a basket built from what the average urban household buys. BLS says so itself: the index doesn’t necessarily measure your own experience of price change. A household that buys a lot of eggs and coffee and very little of anything else lives in a different index. The good news is that the method behind the official number is simple enough to copy at the kitchen table, with two receipts and a calculator.
How the official number is built
Every month or two, BLS data collectors go back to the same stores and price the same items. Not “coffee” in general: one specific product, in one size, at one outlet. The change in that item’s price is the raw material. When a product shrinks, the price is converted to a standard size first. BLS’s own example is a $5.99 tub of ice cream that goes from 64 to 60 ounces: the shelf price didn’t move, and the index records a 6.7% increase.
That’s the whole trick, and it’s the part most home calculations skip. Same product, same size or converted to a unit, same place. Your version follows the same rules.
Doing it with your own receipts
- Find two receipts from the same store, about a year apart. A year smooths out the week-to-week sale noise. Same store, because a different store is a different price for reasons that have nothing to do with inflation.
- List the products that appear on both. Only the same product: same brand, same variety. Store-brand milk then and name-brand milk now is a swap, not a price change. Five to ten matches is enough to say something.
- Put each price on the same footing. Anything sold by weight goes in as the price per pound, not the line total. Anything whose package changed size goes in per ounce or per count, which means checking the package, because most receipts don’t print the size. When the unit price is a fair comparison, and when it isn’t, is its own question.
- Compare sale with sale, or regular with regular. If last year’s egg price was on sale and this year’s wasn’t, you’re measuring the sale. Some receipts print the regular price under a discounted line; when yours does, use it.
- Work out each item’s change: new price divided by old price, minus one.
A worked example
These numbers are an illustration, not a real receipt. Five things bought at the same store a year apart, each on the same footing:
| Item | A year ago | Now | Change |
|---|---|---|---|
| Eggs, dozen | $3.29 | $3.99 | +21.3% |
| Whole milk, gallon | $3.79 | $3.89 | +2.6% |
| Ground coffee, per ounce | $0.749 (12 oz at $8.99) | $0.856 (10.5 oz at $8.99) | +14.3% |
| Bananas, per pound | $0.59 | $0.62 | +5.1% |
| Sandwich bread, loaf | $3.49 | $3.49 | 0% |
The coffee is the one a quick look would miss: the bag costs exactly what it did, and the coffee in it costs 14% more.
Now combine them. The plain average of the five changes is 8.7%. But nobody buys one of each. Say a typical month is two dozen eggs, four gallons of milk, one 12-ounce bag’s worth of coffee, three pounds of bananas and four loaves. Price that same month at both years’ prices:
| At last year’s prices | At this year’s prices | Change | |
|---|---|---|---|
| The same month of shopping | $46.46 | $49.63 | +6.8% |
6.8%, not 8.7%. Eggs went up the most but are a small part of the spending; milk barely moved and is the biggest part. Holding the quantities fixed and weighting by what you spend is the closer copy of how the official index combines items, and it’s the more honest number for your household.
What doesn’t belong in the number
Plenty of things make a grocery bill bigger without being inflation, and the method above deliberately leaves them out:
- switching to a different brand or a bigger pack;
- shopping at a different store;
- buying more of something, or buying it more often;
- things on this year’s receipts that weren’t on last year’s at all.
They’re real, and they can explain more of a bigger bill than prices do. But they answer a different question: not “how much more do the same things cost?” but “why is my bill higher?”, which has its own way of being taken apart.
Reading the result without over-reading it
- Five or ten items is a small basket. One product with a big jump can carry the whole result. Look at the item list before the total.
- It isn’t comparable to the official 2.2% line for line. That figure covers the whole national basket, including everything you never buy. A personal number that comes out higher or lower doesn’t mean either one is wrong.
- “Personal inflation calculators” online usually aren’t personal about prices. The ones I found ask how you split your spending across categories and re-weight the national figures. The prices are still the average household’s, not the ones on your receipts.
- Two receipts give one change. They can’t tell you whether a price went up once or crept up over several months, or whether last year’s price was itself a temporary low.
The receipt from a year ago
The method is easy. The hard part is having last year’s receipt, from the same store, with the same product on it. Most of them went out with the recycling the week they came home, which is why most people’s sense of grocery inflation is a feeling rather than a number. A price book kept by hand is one way around that.
CartEncore is another. Every receipt you give it keeps its own date, including old ones, and every line is kept with the store and the price you paid. For a product it can compare like with like, it shows when its price changed and from what to what. It doesn’t calculate an inflation rate, and it doesn’t look up what other stores charge. It keeps the before-price, so the old receipt doesn’t have to survive.
One product’s prices over time: what one product has cost you →
When it’s the total that went up, not the prices: finding what changed in your grocery bill →