This calculator currently contains data for the UK, US, and Japan using the following sources:
Which inflation indicator does the calculator use?
CPI has several variations. We are taking the following measures country by country:
United Kingdom: CPIH is the CPI plus the homeowner’s imputed rent.
United States: CPI-U (not seasonally adjusted). Measures price changes for all urban consumers (approximately 93% of the total US population) and includes rental costs attributed to homeowners.
Japan: CPI plus homeowner imputed rent
Need to enter irregular purchases such as flights or electronics?
We recommend using the Inflation Calculator only for regular monthly spending, as the inflation that occurs for one-time purchases will vary depending on when the purchase was made. This approach is great for understanding individual inflation trends. This is the inflation rate experienced by the same monthly basket in the previous month. However, this approach excludes irregular purchases, so it cannot be compared to national inflation rates.
However, you can also use the calculator to find out your personal inflation rate in the following alternative ways:
Last month’s actual spending, including irregular purchases. Using this approach, you can enter all of your actual spending for each category, including irregular purchases if you paid for them in the previous month. This approach is great for understanding the impact inflation is currently having on personal finances. Your personal inflation trend is the rate of inflation you would have experienced if you had made the exact same purchases you made last month the previous month.
Monthly average of all spending. Using this approach, you can include both your regular monthly spending and your average “cost of use per month” for irregular purchases. While this approach is great for comparing individual inflation rates to national inflation rates, it does not necessarily reflect the inflation experienced when making irregular purchases.
If I own a home, how do I enter my housing expenses?
In this calculator, you can enter the amount you will spend on mortgage payments and home insurance under ‘Rent/Mortgage’ and the amount you will spend on repairs and home improvements under ‘Household Goods and Maintenance’. Taken together, these act as a proxy for the owner’s resident housing costs.
Since property purchases are viewed as both an investment and a service, the method of measuring owner-occupant inflation is a little more complicated. As such, it may be treated differently in the Consumer Price Index.
For this calculator, we chose a CPI measure that takes into account the homeowner’s cost of servicing the home in a method called “rental equivalent.” It uses the rent that an owner has to pay for the property they live in as a proxy for the housing services it provides.
Are all items of spending included in the consumer price index?
No, spending on the following products is generally considered outside the consumer price index: Cash gifts, including donations and tips. gambling; credit claims; loan interest payments; taxes not related to consumer goods and services.
Does the Inflation Calculator take into account price fluctuations for different items?
No, this calculator does not:
Where in your country do you buy your products? For example, housing cost inflation is based on national averages rather than price fluctuations in your area.
How are inflation rates calculated for each country?
Although there are some differences between countries, generally the following steps are taken to calculate the inflation rate for each country:
Each month, price collectors record prices for the same set of products from a large sample of shops nationwide and online.
Price changes for a particular product at a particular shop are aggregated into an overall price change for each type of item and indexed to represent the relative price changes for items of that type.
Items are weighted to reflect their relative importance in the overall shopping basket. Weightings are typically based on average household spending and are updated periodically (every 1-2 years) to reflect changes in consumer behavior.
The overall consumer price index is calculated by a weighted average of price changes.
How is personal inflation estimated?
Personal inflation is calculated in a similar way to national inflation, but with a necessary simplification:
First, the calculator collects and calculates the latest and last 12 months of price index data for each spending category from the relevant national statistical agencies of the selected country.
The calculator then defines the weights to apply to each category’s price increase based on the spending inputs provided.
The calculator then mimics the calculations performed by the National Bureau of Statistics to generate monthly overall personal inflation rates from January 2021 through the most recent month for which data are available. In doing so, the calculator assumes that the percentage of spending on each category is the same each month.
Please note that the personal inflation figures we produce may contain rounding errors, as we use published figures that have been rounded by national statistical agencies.
https://www.ft.com/content/95745636-2d21-46aa-b0f1-6bda1c0fdd0b Personal Inflation Calculator: What’s Your Inflation Rate?