Dates & Time calculators

Days between dates, ages, time durations and more.

Each with the formula, a worked example and sources.

• Age CalculatorExact age in years, months and days, plus your next birthday.
• Business Days CalculatorCount business days between dates, or add business days to a date, skipping US federal holidays.
• Date CalculatorAdd or subtract years, months, weeks and days from any date.
• Days Between Dates CalculatorCount the days, weeks, months and weekdays between two dates.
• Hours CalculatorAdd up hours worked from start and end times, minus breaks, with pay.
• Military Time ConverterConvert between 12-hour (AM/PM) time and military (24-hour) time.
• Time CalculatorAdd or subtract hours, minutes and seconds from a time, or add two durations.