Personalized inflation simulator

Describe your consumption, compute your personalised inflation rate and compare it with the national average in a few clicks. None of the information you enter is stored.

What inflation for your own consumption?

The Consumer Price Index (CPI) measures the average change in the prices of the goods and services consumed by households in France. To compute it, each product is taken into account according to its weight in the spending of all households: the price of a baguette, for example, does not carry the same weight as rents or fuels.

This indicator has the advantage of simplicity, being representative of households as a whole. Each household, however, has its own consumption habits. Depending on the share of its budget devoted to housing, transport, food or leisure, it may be more or less affected by price rises and falls.

The simulator lets you compute a personalised price index, by adapting the weight of each consumption category to your own spending breakdown.

What is the price index simulator?

The price index simulator lets you compute a personalised index, view its change since 1997 and compare it with the overall Consumer Price Index (CPI) computed by Insee, as well as with the indices of 13 broad product groups.

The personalised index is computed from the spending amounts you enter for 13 broad groups of goods and services.

Which spending category contributes most to my personalised inflation?

Once your personalised index is computed from your own spending breakdown, you can see which consumption categories contribute most to your inflation and compare their contribution with the one observed on average for all households.

Documentation

User guide

The price index simulator lets you compute a personalised index, view its change since any year from 1997 onwards, and compare it with the overall Consumer Price Index (CPI) computed by Insee, as well as with the indices of 13 broad consumption categories.

The personalised index is computed from the amounts you enter for 13 broad consumption categories of goods and services.

The data you enter in this simulator is not sent to Insee.

Calculate a personalised index

You can compute a personalised index and view the curve of its change by editing the spending amounts associated with each consumption category.

The “Your expenses” section lets you enter, for each of the 13 consumption categories, an amount in the “Your value” field. Remember to specify whether the spending is monthly or annualised. Your personalised index curve adjusts and lets you compare it with the Consumer Price Index computed by Insee on the same principle, but using the average spending of all French households.

The “Average” column holds the average consumption spending of all households.

Next to each consumption category, a checkbox lets you display that category’s price index on the chart.

By default, your personalised inflation is compared with overall inflation from 1997 to today. You can adjust this period with the sliders in the “Period” section.

Understand which spending categories drive inflation

Once your personalised index is computed, you can tell whether you are more or less affected by inflation than the average French household. To go further, the “Breakdown” tab lets you identify the consumption categories that contribute most to your personalised inflation, comparing their contribution with the one observed for all households.

Calculation method and limitations

The personalised index is computed from the spending breakdown you enter and the price indices of the 13 broad consumption categories of the eCoicop V2 classification.

The indices of these categories cannot be aggregated directly. Indeed, the CPI indices are Laspeyres indices chained annually. For each year A, the simulator therefore first computes, for each consumption category, an index on a December A-1 = 100 base. These indices are then aggregated according to the spending breakdown you entered. The resulting annual indices are finally chained to build your personalised index over the whole period, on a principle comparable to the one used for the CPI.

The reference amounts shown in the “Average” column correspond to the average monthly spending per inhabitant within the scope of the consumer price index. They are computed from actual final consumption (including social security reimbursements), excluding imputed rents of owner-occupiers and life insurance charges (source: National accounts), divided by the French population (source: population census).

The personalised index is an estimate, with several limitations:

Your spending breakdown is assumed to be constant over time. To compute the CPI, the weight of each consumption category is updated every year to account for changes in household consumption. In the simulator, the breakdown you enter is instead applied to the whole period;
The computation is based on broad consumption categories. The indices of these categories are themselves computed from more detailed indices. Limiting the input to 13 categories keeps the simulator simple to use, but does not allow the exact composition of your spending within each category to be taken into account;
The data used is rounded. The indices used for the computations are those published on insee.fr, rounded to two decimals. The weightings used are also those published on insee.fr, which are rounded and may therefore differ slightly from the exact values used to compute the CPI.

Because of these approximations, the index obtained using the amounts of the “Average” column is not strictly identical to the official CPI. Over a 30-year period, the gap remains below half an index point.