Date and time guide: timestamps, zones, workdays and durations

Convert integer Unix timestamps and known-offset dates, with UTC and IANA-zone display.

Steps

1. Choose Unix timestamp or ISO date with timezone before entering a value.
2. For a Unix timestamp, select seconds or milliseconds; choose an IANA display time zone, then convert.
3. Review UTC and local results. Copy an individual value or download the full result.

Available options

Convert from

Unix timestamp · Known-offset date

Timestamp unit

Seconds · Milliseconds

Display time zone (IANA)

UTC

Capabilities and limits

• Primary text allows 1 MiB UTF-8. Unix values must be integer seconds or milliseconds with an explicit unit; decimal .00, exponents and fractional Unix values are unsupported.
• UTC and displayed local dates both require Gregorian years 0001–9999. UTC milliseconds range from −62135596800000 to 253402300799999, retaining millisecond precision and exact decimal seconds.
• Use YYYY-MM-DDTHH:mm with optional seconds and up to three fractional second digits, followed by Z or a known ±HH:mm offset. −00:00, leap seconds and offset-free dates are unsupported. Display zones require runtime IANA names or UTC; local, system, UTC+3 and +03:00 display parameters are unsupported.
• The display-zone parameter allows 100 UTF-8 bytes and all active parameter values together allow 2 MiB. Calculation stops after 10 seconds; failure or cancellation produces no partial result. Adjust the input and retry.

Resolve time zones and daylight-saving ambiguity, or format an instant in UTC. Convert a local wall-clock time between IANA timezones using browser timezone data. Nonexistent DST times are rejected; repeated times require an explicit earlier or later choice.

Steps

1. Choose time-zone conversion or UTC formatting above the input.
2. Enter a date-time; conversion needs source and target IANA zones and a choice for repeated local times.
3. Review the Date result, then use the available copy or download controls.

Available options

Task

Time zone conversion · UTC formatting

Source IANA timezone

UTC

Use a zone name such as Asia/Shanghai or America/New_York. A fixed UTC offset cannot describe daylight-saving rules.

Target IANA timezone

Asia/Shanghai

Repeated local time

Ask me to choose · Earlier occurrence · Later occurrence

Format

YYYY-MM-DD HH:mm:ss

Capabilities and limits

• Pasted text is limited to 1 MiB; review the result before using it.
• Tokens: YYYY MM DD HH mm ss. Output uses UTC, including when the input has a different offset.
• Output uses UTC; any input offset is applied before conversion.
• Files and input are processed in this browser. No account needed.

Compare calendar dates using UTC day arithmetic, without allowing timezone offsets to create 23- or 25-hour day errors. Choose whether to include both endpoints.

Steps

1. Enter the date (yyyy-mm-dd) for days between dates. Fill in the second input as well.
2. Check your input, then select “Calculate days”.
3. Review the Duration result, then use the available copy or download controls.

Available options

Count both endpoint dates

Off by default

Capabilities and limits

• Pasted text is limited to 1 MiB; review the result before using it.

Add years and months first, clamp to the final valid day of the destination month, then add days. This is calendar arithmetic, not a maintained holiday or business-day service.

Steps

1. Enter the date (yyyy-mm-dd) for add or subtract dates.
2. Review Years, Months, Days before selecting “Calculate date”.
3. Review the Date result, then use the available copy or download controls.

Available options

Years

0

Months

0

Days

0

Capabilities and limits

• Pasted text is limited to 1 MiB; review the result before using it.

Time a task, pause for breaks, and record laps. The running time appears in the browser tab title. Copy the current elapsed time for a work log or copy the lap table; this page does not keep project history.

Steps

1. Select Start to begin the stopwatch.
2. Select Lap while running to record a split; pause and resume without losing elapsed time.
3. Copy the current elapsed time or lap table before switching tools, resetting, refreshing, or closing the page.

Capabilities and limits

• Timer state and lap times stay in this page only. Switching tools, refreshing, or closing the page resets them.

Set a duration and keep a visible countdown beside your task. Pause or resume as needed; the page shows a finish notice when time runs out. Keep the tab open, since browser restrictions can delay the notice.

Steps

1. Set hours, minutes and seconds to a total greater than zero.
2. Select Start. Pause and resume without losing the remaining time.
3. Keep the page open for the finish notice. Pause before editing the duration; an edit starts a new countdown.

Available options

Hours

0

Minutes

5

Seconds

0

Capabilities and limits

• This countdown stays in the current page only. Switching tools, refreshing, or closing the page resets it.

Find a target date by adding working days, or count working days in a date range. Choose your workweek and either enter excluded dates yourself or apply the standard US federal holiday calendar.

Steps

1. Choose Add working days or Count between dates. Enter the start date and a working-day count or an end date.
2. Choose your workweek, holiday calendar and any extra excluded dates in YYYY-MM-DD format.
3. Calculate, review the target date or count, then copy it or download the JSON.

Available options

Calculation

Count between dates · Add working days

Start date

Enter as needed

The date control may display your browser’s local format; the selected value is stored as YYYY-MM-DD.

End date

Enter as needed

The date control may display your browser’s local format; the selected value is stored as YYYY-MM-DD.

Working days to add

Enter as needed

Integer 0–10,000; the start is excluded and zero keeps the start.

Include end date

On by default

Holiday calendar

Manual dates only · Standard US federal holidays

Extra dates to exclude

Enter as needed

One YYYY-MM-DD date per line, or separate with commas. Extra dates are combined with the selected calendar.

Capabilities and limits

• Use YYYY-MM-DD calendar dates in years 0001–9999, without time or zone. Addition excludes the start and zero keeps the original date; ranges include the start and optionally the end. Endpoint difference allows 36,600 days, so including both endpoints allows 36,601 dates.
• Add 0–10,000 working days. At most 36,600 dates after the start are visited; if the target cannot be found, the whole calculation is refused. Exclusion text allows 60,000 UTF-8 bytes and 5,000 original date tokens; duplicates use token capacity but are deduplicated for counting. Active parameter values together allow 2 MiB.
• The US federal preset requires a standard Monday–Friday workweek and calculation years 2000–2099; Juneteenth begins in 2021. Current recurring Friday/Monday observation rules do not predict future laws, regional Inauguration Day, state/employer holidays or one-off closures; supply extra dates manually.
• The complete result retains every date actually excluded. Manual dates outside the period or on non-workdays are counted as ignored. Calculation stops after 10 seconds; cancellation or failure provides no partial result.

Enter a calendar date to find its ISO week code, week-year and Monday–Sunday range. ISO weeks start on Monday, and week 1 contains the year’s first Thursday. Dates near New Year can belong to a different week-year.

Steps

1. Choose a date or use Today or the New Year example.
2. Calculate the ISO week, then check the week-year and Monday–Sunday range, especially near New Year.
3. Copy the ISO week code or number, or download the JSON result.

Available options

Calendar date

Enter as needed

The control may display your browser’s local format; the selected value is stored as YYYY-MM-DD and stays on that calendar day.

Capabilities and limits

• Choose a calendar date with the browser control. Its display format may vary, but the value is stored as YYYY-MM-DD without a time or time zone.
• This follows ISO 8601. Some US calendars use Sunday-start weeks and number them differently.
• The calculation runs in your browser; no account or upload is needed.

Paste one duration per line to total work logs, media clips or other elapsed time. Use H:MM:SS or M:SS (minutes:seconds); prefix a line with - to subtract a break. The total keeps hours above 24.

Steps

1. Paste or type one duration per line. A leading minus sign subtracts that duration.
2. Check the total, added and subtracted amounts, then expand the line-by-line running totals if needed.
3. Copy the total or exact seconds, or download the total as TXT.

Capabilities and limits

• Each nonblank line must be H:MM:SS or M:SS with whole seconds. In the two-part form, 1:30 means 1 minute 30 seconds; write 1:30:00 for 1 hour 30 minutes.
• Up to 500 nonblank lines and 40,000 characters; each hour or minute count is at most six digits. Times of day, dates and fractions of seconds are not accepted.
• Calculation runs in your browser; no account or upload is needed.

Switch between hours and minutes and decimal hours. For example, 7:45 becomes 7.75 hours; 7.63 decimal hours becomes 7:37:48. Minutes after a colon use base 60, while decimal digits are fractions of an hour.

Steps

1. Choose duration to decimal hours or decimal hours to duration.
2. Enter one value. When converting to decimal, choose 2, 4 or 6 places and check the preview.
3. Convert, then copy the main value or download the TXT result. Check the displayed duration before entering rounded values in a timesheet.

Available options

Conversion direction

Duration → decimal hours · Decimal hours → duration

Decimal places

2 places · 4 places · 6 places

Capabilities and limits

• Convert one duration or decimal value at a time. Durations use H:MM or H:MM:SS; decimals accept up to nine fractional digits and a maximum of 1,000,000 hours.
• For duration to decimal, choose 2, 4 or 6 places. Decimal to duration rounds to the nearest whole second. A rounded decimal may not reconstruct the exact original duration.
• This converts elapsed durations only. It does not calculate clock-in/out times, breaks, overtime, pay, dates or time zones. Input stays in your browser.

Create one event with a clear time zone, optional location and reminder, then download an ICS file for Google Calendar, Outlook or another calendar app. Review the imported event before sharing.

Steps

1. Enter a title and choose timed or all-day.
2. Set the start and end, choose the event time zone, and optionally add a location, description or reminder.
3. Create the file, review the event summary, download the ICS, and check the imported event in your calendar.

Available options

Event title

Enter as needed

Event type

Timed event · All-day event

Start time

Enter as needed

End time

Enter as needed

Time zone

Device time zone · UTC · IANA time zone

First day

Enter as needed

Last day (included)

Enter as needed

Reminder

No reminder · 10 minutes before · 1 hour before · 1 day before

Location (optional)

Enter as needed

Description (optional)

Enter as needed

Capabilities and limits

• One event per file. No invitations, recurring events, live calendar sync or account connection.
• Timed events are saved as UTC instants; the target calendar controls how they appear and whether reminders are honored. All-day end dates are inclusive on this form.
• Event details are processed in this browser; nothing is uploaded.

Paste a decimal or hexadecimal FILETIME value to read the UTC time, or convert an ISO date back to ticks. The full seven fractional digits are kept.

Steps

1. Choose FILETIME → UTC or ISO date → FILETIME.
2. Paste a decimal value, a hexadecimal value containing A–F, or a 0x-prefixed hexadecimal value. For the reverse direction, enter an ISO date or offset-aware date-time.
3. Check the live preview, convert, then copy the exact UTC time, decimal ticks or hex value.

Available options

Direction

FILETIME → UTC · ISO date → FILETIME

Capabilities and limits

• FILETIME counts 100-nanosecond intervals from 1601-01-01 UTC. This page displays UTC dates through year 9999.
• A date-time needs Z or a numeric UTC offset; a date alone means midnight UTC. Leap seconds are not supported.
• Zero is the FILETIME epoch, but some Active Directory fields use zero as a special value. Interpret field semantics in the source system. Input stays in this browser.

Paste a YouTube API duration or another ISO 8601 duration to see readable elapsed time, each component and exact total seconds. Calendar years and months need a start date for an exact second count.

Steps

1. Paste an ISO 8601 duration, for example PT1H46M57S from a video API.
2. Check the readable time and the component breakdown. If years or months are present, use the calendar warning instead of a fixed second total.
3. Copy the readable time or exact seconds, or download the structured JSON.

Capabilities and limits

• Supports standalone weeks, a leading minus sign and up to nine fractional digits on the smallest unit. Weeks cannot be mixed with date or time units.
• Years and months have variable lengths. When either is nonzero, the exact total seconds and clock are unavailable without a start date.
• Values are processed in your browser. One component may be at most one billion.