The API
Every page is also JSON. Put /api in front of the address.
GET /api/1990/100 — £100 in 1990 today: result, multiplier, what it buys, houses and wages, and a card URL.
GET /api/1990/100/2005 — between two years. Add ?series=cpi for CPI.
GET /api/income/40000 and /api/income/40000/net — the full tax breakdown, marginal rate, employer cost and income percentile.
GET /api/nhs/1000000 — how long it lasts, and the same sum against every other budget.
GET /api/series — the raw annual tables behind the inflation pages.
No key. No rate limit for now. Responses carry cache headers and the data changes monthly, so cache freely.
Use pound.one with an AI assistant
Read the MCP connection guide for setup instructions, tool inputs and example prompts. Registry metadata describes the hosted endpoint.
Add a remote MCP server in an assistant that supports Streamable HTTP. Set the server URL to https://pound.one/mcp and choose no authentication. There is no API key or account to create.
The assistant can adjust pounds for inflation, calculate take-home pay in England, Wales or Northern Ireland, and compare a sum with public spending. Try “What salary today matches £30,000 in 2000?” or “How long would £1bn fund the NHS?”
adjust_for_inflation— amount, starting year, optional ending year and RPI or CPI.calculate_take_home— annual amount in whole pounds, region, and gross-to-net or net-to-gross mode. Scotland is not covered.compare_public_spending— amount and budget, with comparisons against the other budgets.
Every result includes sources, data periods, assumptions, a result link and a share-card link. “Now” means the latest available observation. The NHS comparison uses England's DHSC day-to-day budget; other spending figures have their own scope.
Tool calls are counted by tool, outcome and response time. Calculator inputs are not stored in MCP analytics. Result share links carry campaign tags so we can count visits from assistants.