# Calendar date rounder

## World's simplest time tool

With this browser-based application, you can round a calendar date up, down, or to the next nearest date. You can adjust the rounding precision in the options and round the date to a day, month, quarter, year, ten years, and century. You can quickly switch between the three rounding methods and instantly get the rounded date in the output. Created by computer nerds from team Browserling.

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Calendar date rounder tool
What is a calendar date rounder?

This is a quick online utility for rounding calendar dates. It can round any date to any precision up, down, or to the closest date. When a date is rounded, the least significant date components are set to the smallest possible value (zero for hours/minutes/seconds and one for years/months/days). For example, if the date "2022-05-21 14:23:58" is rounded down to days, then the hours, minutes, and seconds components turn into zeros "2022-05-21 00:00:00". Similarly, when this same date is rounded down to months, we get "2022-05-01 00:00:00", to quarters: "2022-04-01 00:00:00", to years: "2022-01-01 00:00:00", to decades (tens of years): "2020-01-01 00:00:00", and to centuries: "2000-01-01 00:00:00". You can also round time part of a date to an hour, 30 minutes, 15 minutes, 10 minutes, 5 minutes, 1 minute, 30 seconds, 10 seconds, and 5 seconds. In the options, you can switch between three rounding methods: "Round a Date Up", "Round a Date Down", and "Round Date to Nearest". Rounding up increases the date components towards the next largest day/month/year/century. For example, the date "2022-05-21 14:23:58" will become "2022-06-01 00:00:00" when rounding the months up. Rounding down decreases the date components to the beginning of the smallest day/month/year/century. For example, when rounding the date "2022-05-21 14:23:58" down to months, we get "2022-05-01 00:00:00". Rounding to the nearest date determines on its own whether to increase or decrease the date. For example, when rounding the date "2022-05-21 14:23:58" to the nearest day, it becomes "2022-06-01 00:00:00" (because it's 10 days from June and 21 from May), and the date "2022-05-03 14:23:58" becomes "2022-05-01 00:00:00" (because it's 3 days from May and 28 days from June). You can round as many dates as you want at the same time if you enter them one per line to the input. The rounding results can be copied or saved from the output field. Timeabulous!

Calendar date rounder examples
Click to use

Round a Date to a Day

In this example, we round up three calendar dates with a precision of one day. Every date that has a clock time part greater than midnight turns into the start of the next day. If the clock time is exactly midnight, then the time is already rounded to a day and doesn't change.

2000-11-24 05:20:50
2034-05-31 16:00:00
2050-02-12 00:00:00

2000-11-25 00:00:00
2034-06-01 00:00:00
2050-02-12 00:00:00

**Required options**

Use the ceil method to
round a date up.

Round Months Down

This example sets each date to the beginning of the month. Here the rounding algorithm uses the "Round a Date Down" mode with a precision of 1 month. As a result, all calendar days are set to "01" and the time is reset to 00:00:00.

1995-11-23 17:30:00
1980-06-01 00:00:00

1995-11-01 00:00:00
1980-06-01 00:00:00

**Required options**

Use the floor method to
round a date down.

Find the Middle of the Year

In this example, we use our date rounding program to guess the middle of a leap year and a common year. We set the options to round the given dates to the closest year and enter several leap years (2024) and several common years (2025) in the input that have a difference of 1 second. We can see that the middle of a leap year falls on the midnight of July 2nd (on 2024-07-02 00:00:00) and the middle of a regular year falls on the noon of July 2nd (2025-07-02 12:00:00).

2024-07-01 23:59:59
2024-07-02 00:00:00
2025-07-02 11:59:59
2025-07-02 12:00:00

2024-01-01 00:00:00
2025-01-01 00:00:00
2025-01-01 00:00:00
2026-01-01 00:00:00

**Required options**

Automatically determine whether
to use ceil or floor method to
round a date.

Round Dates in a Quarterly Financial Report

In this example, we are working with a quarterly financial report for q2, 2022. As all dates fit in the interval 2022-04-01 to 2022-07-01, we round them down to the q2 start date. This way all output dates start on the first day on q2, 2022, which is "2022-04-01".

2022-04-28 12:30:00
2022-05-01 06:45:30
2022-05-14 13:05:00
2022-05-31 00:00:00
2022-06-03 04:00:00
2022-06-26 15:00:50

2022-04-01 00:00:00
2022-04-01 00:00:00
2022-04-01 00:00:00
2022-04-01 00:00:00
2022-04-01 00:00:00
2022-04-01 00:00:00

**Required options**

Use the floor method to
round a date down.

Round a Date to 10 Years

In this example, we round up three different dates to the next decade. After rounding, the months and days are set to the beginning of the year (January 1) and the time is reset to midnight. The year is turned into the next largest year divisible by ten. As a result, the first year is rounded to 2030, the second to 2040, and the third to 2050.

2022-06-25 00:00:00
2038-10-10 10:10:10
2044-01-12 09:00:00

2030-01-01 00:00:00
2040-01-01 00:00:00
2050-01-01 00:00:00

**Required options**

Use the ceil method to
round a date up.

Which Century is a Date Closest To?

In this example, we load a list of random dates from 2000 to 2100 and we want to determine which century each date is closest to. To find the answer, we select the century round precision and switch to the nearest rounding mode. As soon as we do that, we get the answer to our question and all dates are shifted back either to 2000 (if they are closer to 2000) or shifted forward to 2100 (if they are closer to 2100).

2002-03-27 00:53:57
2090-09-27 21:47:19
2005-10-10 01:17:37
2030-07-22 13:10:02
2095-12-12 16:59:45
2089-10-28 13:04:01
2058-03-13 13:13:48
2022-07-21 06:12:01
2057-12-13 00:56:07
2004-04-28 06:36:49

2000-01-01 00:00:00
2100-01-01 00:00:00
2000-01-01 00:00:00
2000-01-01 00:00:00
2100-01-01 00:00:00
2100-01-01 00:00:00
2100-01-01 00:00:00
2000-01-01 00:00:00
2100-01-01 00:00:00
2000-01-01 00:00:00

**Required options**

Automatically determine whether
to use ceil or floor method to
round a date.

Pro tips
Master online time tools

You can pass input to this tool via

__?input__query argument and it will automatically compute output. Here's how to type it in your browser's address bar. Click to try!
https://onlinetimetools.com/round-calendar-date

__?input__=2000-11-24%2005%3A20%3A50%0A2034-05-31%2016%3A00%3A00%0A2050-02-12%2000%3A00%3A00&round-to=to-1-day&round-up=true
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