날짜 계산기

Calculate date differences, add or subtract time from dates, find weekdays, and business days. Handles leap years and step-by-step solutions.

Your Input

Format: YYYY-MM-DD

Must be on or after start date

Select a calculation type, enter your dates, and click Calculate to see results with step-by-step solutions and visualizations.

전체 사용자 가이드

날짜 계산기란 무엇입니까?

A date calculator performs date-related calculations: difference between two dates, add or subtract time periods (years, months, weeks, days), days since a past date or until a future date, and which day of the week a date falls on. It handles leap years, varying month lengths, and year boundaries.

Difference = End Date − Start Date  |  Business days = weekdays only (Mon–Fri)

Use it for project planning, countdowns, age or tenure, deadlines, and scheduling.

Date Format

Use YYYY-MM-DD (e.g. 2025-02-15). Dates from year 1 to 9999 are supported.

계산 유형

날짜 차이

Exact difference in years, months, days, weeks, and business days (Monday–Friday, excluding weekends).

더하기/빼기

Add or subtract years, months, weeks, or days from a date. Result shows the new date and day of the week.

이후 일수

How many days have passed since a past date (e.g. since birth, since an event).

남은 일수

How many days remain until a future date (countdowns, deadlines).

주일

Find which day of the week (Monday, Tuesday, …) a given date falls on.

이 계산기를 사용하는 방법

  1. Select a calculation type (Date Difference, Add/Subtract, Days Since, Days Until, or Weekday)
  2. Enter the required dates and values in the form
  3. Click 'Calculate' to see the result
  4. Review the main result, detail cards (when applicable), and step-by-step solution
  5. Use the chart for date difference or days since/until to see a visual breakdown
  6. Click 'Reset' to set all dates to today and clear results

결과 이해

Main result

The primary answer: formatted difference (e.g. 2 years 3 months), result date, number of days, or weekday name.

Detail cards

For date difference: total days, weeks, months, and business days in a compact grid.

Step-by-step

Shows how the calculation was performed, including formulas and intermediate values.

영업일 이해

Business days are weekdays (Monday through Friday); Saturdays and Sundays are excluded. Used for project deadlines, shipping estimates, work schedules, and contract terms. This calculator does not exclude holidays.

날짜 계산 방법

상대 델타: Precise year, month, and day differences; accounts for varying month lengths and leap years.

시간 제한에서: Total days between dates (simple date subtraction).

Business days: Count of weekdays (Mon–Fri) between two dates.

중요 사항

  • All calculations account for leap years and varying month lengths.
  • Business days exclude weekends only; holidays are not excluded.
  • Dates must be between year 1 and 9999. Use YYYY-MM-DD format.

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