The basket behind the number
The Consumer Price Index tracks a fixed basket of goods and services — housing, food, transportation, medical care — weighted by how much the average household actually spends on each. Your personal inflation rate can differ substantially depending on your own spending mix.
Why your bill feels worse than the headline
Grocery prices are volatile and highly visible — you notice a $6 carton of eggs every week. Housing costs, the largest CPI component, move slower and lag real-time rent changes by design, which is why CPI often understates what renters are actually feeling in real time.
What actually moves the number
Energy and food are the most volatile inputs, which is why "core CPI" strips them out to see the underlying trend — useful for policy, less useful for your actual weekly bill.
