Date Span

Date Span is a date calculator for the questions that come up every week: how many days until a deadline, how many working days a project has, which week number a date falls in, or what the date will be 90 days from now.

The main tool counts the span between two dates. Pick a start and an end date on the built-in calendar and you get the total in days, the same span as weeks and days and as years, months and days, plus business days, weekend days and total hours. Switch on "Include end date" when both ends should count. If the end comes before the start, the counts turn negative and one tap swaps the dates.

Under the total sits the span ribbon: a strip of months, each as wide as its real number of days, with the counted range drawn in coral and a pin at each end. Longer spans switch to years or decades, so even a span of several decades fits on one line.

Add / subtract moves a date by days, weeks, months, years or business days. Month steps stop at the end of a shorter month, so January 31 plus one month is February 29 in a leap year and February 28 otherwise.

Day info shows the weekday, ISO 8601 week number and week-year, day of the year, days left in the year, quarter and leap year for any date from 1600 to 2400.

Countdowns keeps up to 15 named dates, such as birthdays, deadlines or trips, with the days left or the days since. Yearly dates roll over to the next anniversary.

Holidays is your own list of days off. Every weekday on it is left out of business-day counts, and each entry can happen once or repeat every year. No country holiday data is built in.

The last ten calculations stay on the home screen, one tap from being opened again.

Features:
- Days between two dates, with or without the end date
- Weeks and days, years/months/days, business days, weekend days and total hours
- Span ribbon that draws the counted range to scale
- Add or subtract days, weeks, months, years or business days
- ISO week number, day of year, quarter and leap-year check
- Up to 15 countdowns, with yearly repeat for birthdays and anniversaries
- Your own holiday list, one-off or yearly
- History of the last 10 calculations
- Three date styles and a Monday or Sunday calendar week

Date Span needs no network connection and has no accounts and no ads. Everything you enter is kept on this phone and nowhere else.