日付・時間 計算機

Calculate days, hours, and minutes until your next birthday. Enter date of birth — see exact countdown and star sign. Free.

Current moon phase and full moon calendar. Full formula with variable legend, worked example and step-by-step chemistry solution.

ISO week number for any calendar date. Enter your values — see the result with formula, examples, and step-by-step working. Free.

Convert times between world time zones instantly. Enter source time and city — see local time with UTC offset and DST status. Free.

Business days between two dates. Enter your values — see the result with formula, examples, and step-by-step working. Free.

Is any year a leap year and when is the next one?. Enter your values — see the result with formula, examples, and step-by-step working. Free.

Calculate your age in the Korean age system. Enter date of birth — see Korean age and comparison to international age. Free.

Calculate your retirement date by country. Instant result with amortization table, formula and chart. Free financial calculator.

Convert Gregorian dates to lunar calendar. Fast and accurate result with formula, step-by-step method and unit overview. Free tool.

Count exact days between any two calendar dates. Enter start and end date — see days, weeks, months, business days, and weekends. Free.

Add or subtract days, weeks, or months from any date. Enter the date and duration — see the result with day of week. Free.

Count working days between two dates excluding weekends. Enter your values — see the result with formula, examples, and step-by-step working. Free.

Calculate your age on any past or future date. Enter DOB and target date — see age in years, months, and days on that date. Free.

Find what day of the week any date falls on. Enter any date — see the weekday, ISO week number, and days from today. Free.

Calculate full and partial weeks between two dates. Enter start and end date — see complete weeks and remaining days. Free.

Find the fiscal or calendar quarter for any date. Enter the date — see current quarter, remaining days, and fiscal year calendar. Free.

Get sunrise and sunset times for any location and date. Enter city or coordinates — see sunrise, sunset, and hours of daylight. Free.

Add or subtract days, weeks, or months from any date. Enter start date and duration — see the resulting date with day of week and countdown. Free.

Calculate the optimal nap length to avoid sleep inertia. Enter your sleep stage preference — see ideal nap duration and best time of day. Free.

Map your daily energy peaks and dips based on wake time and chronotype. Enter your values — see the result with formula, examples, and step-by-step working. Free.