Background article, updated October 23, 2026. Our earlier Canadian collection has stored prices dated December 11, 2025 through March 21, 2026, with gaps. The current collection began March 22, 2026. See collection dates and gaps.
A weekly grocery price measure is useful when you can explain what changed. Were the same products priced at the same stores? Did a sale end? Were some prices missing? Those questions matter before you interpret the headline number.
Compare like with like
Keep each product's chain, store, size and price date with the price. Compare the same item at the same store in both periods. Otherwise, a switch to a larger package or a different set of stores can look like a price change.
A missing price is a gap in the data. It should not be filled with the previous price just to make a chart look continuous.
Read the weekly index
Vynn's free weekly price index compares the same items at the same stores between weeks. The page shows the latest week with enough prices to calculate a result. Its weekly releases keep the figures and explanation for each published week.
Use the index to follow the stores it tracks. Use an individual product's history when your question concerns that product or chain.
Keep official inflation separate
Statistics Canada's CPI is designed to measure price change for a basket based on household spending. A weekly grocery dataset has a different set of products and stores. The CPI questions and answers explain the official measure.
Compare the same dates when using the sources together. A difference between them is something to investigate, not proof that one predicts the other.
Keep a record of your choices
Write down the products, stores and dates you used, along with any gaps. Save the calculation so another person can repeat it. If the source later changes, you can identify which revision your result used.
Check the sample data or get a free API key to start your own comparison.