How it works
pound.one answers three questions about British money — what it was worth, what you keep, and how long it lasts — using only official data, and it shows its working.
Addresses are the interface
/1990/100 is £100 in 1990, today. /1990/100/2005 compares two years. ?series=cpi swaps RPI for CPI. /income/40000 is a salary; /income/40000/net is a take-home target. /nhs/1000000 is a sum spent on a budget. Every page has a /card.png and an /api/… twin, so a link is the whole product.
Inflation
The default measure is the Retail Prices Index because it is the only official series that runs continuously from 1948. It tends to read a little higher than CPI and is no longer a National Statistic, which is why CPI is offered from 1988. Values before 1987 are chained from the ONS's annual RPI changes.
The "what it buys" lines use the ONS average shop prices behind the RPI — a pint of lager, a pint of milk, a loaf, a litre of petrol, a packet of cigarettes and so on. The ONS stopped publishing them in January 2025, so today's prices are that last reading carried forward with inflation. They are labelled as approximate wherever that applies. First-class stamps are hand-entered from Royal Mail's price history.
House prices are Nationwide's UK average, taken as the mean of each year's quarters. Wages are the ONS average weekly earnings for the whole economy, times 52. Both are means rather than medians, so read the house-to-pay multiple as a trend, not a mortgage quote.
Income
Tax rules are 2026/27 for England, Wales and Northern Ireland; Scotland has its own bands. It assumes an employee on a standard tax code with no pension contributions, student loan, benefits in kind or other income. Employer's National Insurance is shown at 15% above £5,000, ignoring the Employment Allowance. "Working for the Treasury until" is your effective rate as a share of the year — a simpler idea than the Adam Smith Institute's Tax Freedom Day, which counts every tax there is.
Where you rank uses HMRC's Survey of Personal Incomes, 2023-24. It covers the total income of everyone who pays income tax, so it includes pensioners and part-time workers and reads lower than full-time salary tables. Incomes have risen since, so a rank today is a shade flattering.
Spending
Each budget is a single published annual figure with its source beside it. Departmental figures are day-to-day (resource) budgets; capital spending is separate. Spending is treated as spread evenly through the year.
Privacy
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