Calendar Calculations

No more counting days on a calendar!

Adding or subtracting time from dates

10 June + 3 weeks                     | 1 July
April 1, 2019 − 3 months 5 days       | 27 December 2018

12/02/1988 + 32 years                 | 12 February 2020
01.05.2005 + 3 years 2 months 3 weeks | 22 July 2008

3 weeks after March 14, 2019          | 4 April 2019
28 days before March 12               | 12 February
2 months 3 days after June 5          | 8 August

yesterday - 8 weeks 3 days            | 12 July
Yesterday + 1 week                    | 11 June

Getting a date relative to the present

today + 3 weeks | 1 October
now − 1 month   | 5 May

4 days from now | 14 September
3 days ago      | 7 September

Calculations with named holidays

You can use holiday names in date calculations. For example, days until Christmas counts down to Christmas.

For holidays whose dates change each year, specify the year to find the date:

Easter 2027 → March 28, 2027

Supported holidays and special dates

• Christmas: Christmas Eve, Christmas Day, Boxing Day, Orthodox Christmas

• Easter: Good Friday, Holy Saturday, Easter Sunday, Easter Monday, Orthodox Good Friday, Orthodox Easter

• New Year: New Year's Eve, New Year's Day, Chinese New Year's Eve, Chinese New Year

• Ramadan: Ramadan (the start), End of Ramadan

• Hanukkah: Hanukkah (the start), End of Hanukkah

• Other dates: Valentine's Day, Halloween, Thanksgiving (US), Black Friday

These names can be used in calculations regardless of whether the dates are public holidays in your country.

Find the amount of time between two dates

January 10 - February 5         | 3 weeks 5 days

3 March to 30 May               | 2 months 3 weeks 6 days

days since July 15              | 57 days
days till December 25           | 106 days
days between 3 March and 30 May | 88 days

1978 to 2021                    | 42 years

Intervals of time are calculated from midday on the first date to midday on the last date in the interval.

Use the inclusive interval function if you want to include both the starting and ending date in the interval (see below)

Inclusive intervals of time between two dates

April 1 through April 30 in days | 30 days

Week numbers (ISO 8601)

week of year                  | 36
week number on march 12, 2021 | 10

Getting parts of a date

Find a date’s position within the year or month:

day number on March 15, 2024 → 75

day of month on March 15, 2024 → 15

Without a date, day of year and day of month use today.

How many days in a month or quarter

days in Q3            | 92 days
days in February 2020 | 29 days

How much of the year has passed?

Type year percentage to see how much of the current year has elapsed, expressed as a percentage.

You can also use month percentage, week percentage, or day percentage for the current month, week, or day.

Find the midpoint between two dates

midpoint between March 12 and April 5   | 24 March
halfway between today and next Thursday | 13 September

Formatting dates

Use a format pattern to control how a date is displayed:

March 12, 2023 as EEEE, MMM d, yyyy → Sunday, Mar 12, 2023

Here, EEEE gives the weekday name, MMM the abbreviated month, d the day of the month, and yyyy the four-digit year.

Visit NSDateFormatter.com to learn the format symbols and experiment with your own patterns.

Notes on Ambiguity in Calendar Calculations

Ambiguous months

Unlike days and weeks, months are not clearly defined in terms of seconds. Soulver attempts to do the most logical thing given the expression. It's smart at taking into account leap years, and other calendar peculiarities:

Feb 28 + 1 month          | 28 March
January 31 2020 + 1 month | February 29 2020

Dates with unspecified years

A date without the year specified may use either the current year or the following year.

# In December 2019

// next year is assumed, as the nearest January is in the future
January 12 + 3 weeks | 2 February 2020

// this year is assumed, as the month is still recently in the past
November 1 - 5 days  | 27 October 2019