Free calculators built on official calendars
Each tool runs in your browser, sends nothing anywhere, shows its formula and sources, and refuses dates outside the data it has.
- Social Security payment date calculator (US)
Find the month-by-month Social Security (SSA) payment date for your birth-date group, with weekend and federal-holiday adjustments for 2026–2027. - Business days calculator (US federal and Spain, by community)
Count business days between two dates or add business days to a date, skipping weekends and official holidays (OPM for the US, BOE for Spain, by community). - Is it a holiday? US federal holidays, Fed bank closures and Spain by community
Check whether a date is a US federal holiday, whether Federal Reserve Banks are closed, or a working holiday in Spain (nationally or in your community).