UK business days Free
Is a date a UK business day; add or subtract N business days; count business days between dates. Uses official bank holidays per nation.
- cost
- Free then $0.001 / call
- MCP tool
- calculators__uk-business-days
- method
- GET
Free up to 50 calls a day over MCP (500 with a free key), then $0.001 per call by card credit or USDC. Free key · Pay by card
GET https://fourzerotwo.si/v1/calculators/uk-business-days
| Param | Type | Description |
|---|---|---|
| date | string | YYYY-MM-DD |
| add? | integer | Business days to add (negative to subtract) |
| until? | string | Count business days until YYYY-MM-DD |
| nation? | string | england-and-wales, scotland, northern-ireland |
# free: send a free key from https://fourzerotwo.si/free curl -H "X-API-Key: fzt_…" "https://fourzerotwo.si/v1/calculators/uk-business-days?date=2026-12-23" # no key: returns 402 with the price, for x402 agents curl -i "https://fourzerotwo.si/v1/calculators/uk-business-days?date=2026-12-23"
by fourzerotwo
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Distance between postcodes Free
Straight-line distance (km and miles) and compass bearing between two UK postcodes.
- cost
- Free then $0.002 / call
- MCP tool
- calculators__postcode-distance
- method
- GET
Free up to 50 calls a day over MCP (500 with a free key), then $0.002 per call by card credit or USDC. Free key · Pay by card
GET https://fourzerotwo.si/v1/calculators/postcode-distance
| Param | Type | Description |
|---|---|---|
| from | string | Postcode |
| to | string | Postcode |
# free: send a free key from https://fourzerotwo.si/free curl -H "X-API-Key: fzt_…" "https://fourzerotwo.si/v1/calculators/postcode-distance?from=SW1A%201AA&to=CT9%201JD" # no key: returns 402 with the price, for x402 agents curl -i "https://fourzerotwo.si/v1/calculators/postcode-distance?from=SW1A%201AA&to=CT9%201JD"
by fourzerotwo
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Currency conversion Free
Convert between ~30 currencies at the ECB reference rate for today or any date in the last 90 days.
- cost
- Free then $0.001 / call
- MCP tool
- calculators__currency-convert
- method
- GET
Free up to 50 calls a day over MCP (500 with a free key), then $0.001 per call by card credit or USDC. Free key · Pay by card
GET https://fourzerotwo.si/v1/calculators/currency-convert
| Param | Type | Description |
|---|---|---|
| from | string | ISO currency |
| to | string | ISO currency |
| amount? | string | Amount (default 1) |
| date? | string | YYYY-MM-DD (default latest) |
# free: send a free key from https://fourzerotwo.si/free curl -H "X-API-Key: fzt_…" "https://fourzerotwo.si/v1/calculators/currency-convert?from=GBP&to=USD" # no key: returns 402 with the price, for x402 agents curl -i "https://fourzerotwo.si/v1/calculators/currency-convert?from=GBP&to=USD"
by fourzerotwo
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ECB reference rates; GOV.UK bank holidays and ONS postcode data under the Open Government Licence v3.0.