日付と時刻

Calculate the exact time difference between two dates, in years, months, days, weeks, hours, minutes, and seconds.

Calculate your age in years, months, and days based on your birth date.

Convert your dog's age to human years, and calculate their age in dog years.

Add or subtract time durations in days, hours, minutes, and seconds.

Calculate the duration between two specific times, including hours, minutes, and seconds.

Convert days, hours, minutes, and seconds into a single decimal value for easy calculations.

Calculate total work hours, including breaks and overtime, for your timesheet.

A precise stopwatch with millisecond accuracy, perfect for timing events in games, sports, and daily tasks.

Determine if a year is a leap year quickly and accurately.

Convert dates between Gregorian and Lunar calendars.

Convert dates from the Islamic Hijri calendar to the Gregorian calendar.

Convert dates from Gregorian to Hijri and vice versa, supporting various Islamic calendar standards.

Add or subtract days, months, or years from a given date to find a future or past date.

Perform various calculations involving dates, such as adding or subtracting days, and finding the day of the week.

Estimate how long a book or article takes from word count or pages, your reading speed (WPM), and optional daily minutes to see days to finish.

Rough wake-time targets from bedtime, or bed-time ideas from your alarm, using adjustable cycle length (often 90 minutes). Not medical advice.

Add many clip lengths in one go (MM:SS, H:MM:SS, or seconds per line). Great for podcasts, edits, and playlists.

Rough cat years ↔ human years using a common simplified chart. Decimal ages supported—not veterinary advice.

Get ISO week number and ISO year for any calendar date (ISO 8601, week starts Monday).

Count Monday–Friday days between two dates (weekends only; no public holidays).

Words plus words-per-minute to estimate voice-over or audiobook duration.

Show current date and time in two IANA time zones side by side.

2–5 IANA zones, one calendar day, shared local office hours—see which UTC hour starts put everyone in-window (optional Mon–Fri).

Week number since a semester start date (weeks aligned to Mondays).

Flour weight and ingredient % of flour to ingredient grams.

Wall area, coverage per gallon, and coats → gallons needed (rounded up).

Paste segment durations per line; get cumulative chapter markers for descriptions.

Rectangle in feet—length × width to square feet (and approximate square meters).

Decimal hours or total minutes to hours-and-minutes text.

Years, months, and days between two birth dates (calendar-based).

Base hourly rate plus regular and overtime hours—overtime paid at 1.5× for a rough gross total.

If a value grew by P% to reach V, find the original base before the increase.

Two value–weight pairs—weighted mean (e.g. grades and credits).

Convert decimal degrees to degrees, minutes, seconds.

Split a whole second count into hours, minutes, seconds.

Regular, time-and-a-half, and double-time hours in one gross estimate.

Hits and at-bats—batting average to three decimals.

Total bases and at-bats—SLG = TB / AB.

Total decimal hours split into 24-hour days and remainder.

Signed degrees plus minutes and seconds to decimal °.

mAh capacity and average mA load—ideal hours.

US gallons and GPM—hours to fill at steady flow.

Available time, work and break blocks—cycle count.

mAh, average charge mA, and path efficiency—rough hours (educational).

Epoch seconds or ms ↔ local and UTC time strings.

File size (MB) and link speed (Mbps)—ideal seconds.

Non-negative hours to hours + minutes.

Calendar days from today to a date.

Decimal GB and Mbps—ideal seconds.

Numeric UTC offset hours A and B.