Date & Time Tools Tools
Unix timestamps, UTC, ISO 8601, durations, countdowns, calendar helpers, and random date/time utilities. All run in your browser — nothing is uploaded.
Fifty client-side utilities for Unix timestamps, UTC, ISO 8601 durations, countdowns, calendar math (ISO week, leap year, business days), and random date/time values. For a compact two-way timestamp box, see Converters — we link it below. Nothing is uploaded.
Guide: free date & time tools · All free online tools · Timestamp converter · Epoch converter · Random date generator · Days calculator · Unix to UTC · Live Unix time · Parse PT duration · Text tools
Popular Date & Time Tools Tools
Most used tools in this category:
- Unix Timestamp to UTC – Convert Unix seconds or milliseconds to UTC ISO and GMT string. Detects ms vs s automatically. 100% client-side.
- UTC DateTime to Unix – Parse an ISO or UTC date string and get Unix seconds. Runs in your browser.
- Live Unix Timestamp – Current Unix time in seconds and milliseconds, updating live. Copy with one click.
- Seconds to H:M:S – Convert total seconds into hours, minutes, and seconds. No upload.
- Duration Between Two DateTimes – Paste two ISO date-times (one per line) and get the difference in days, hours, and total seconds.
- Parse ISO 8601 Duration – Parse PT1H30M style durations into total seconds and parts.
- Random Time Generator – Pick a random clock time between two HH:mm values. Useful for testing.
- Countdown to DateTime – Enter a target date-time; see time remaining until then.
- Current UTC Time – Live clock showing current UTC date and time. Updates every second.
- ISO 8601 Normalizer – Parse a date string and output normalized UTC ISO 8601.
- ISO Week Number – ISO-8601 week number and year for a given date.
- Business Days Between – Approximate weekdays Mon–Fri between two dates (excluding weekends).
- Random DateTime in Range – Random ISO date-time between two bounds (inclusive).
- Milliseconds ↔ Unix Seconds – Convert between Unix seconds and milliseconds. Bidirectional.
- Time Ago – How long ago was this Unix timestamp or ISO date?
- Add Duration to DateTime – Start date-time plus days, hours, minutes offset.
All Date & Time Tools Tools
Unix Timestamp to UTC
Convert Unix seconds or milliseconds to UTC ISO and GMT string. Detects ms vs s automatically. 100% client-side.
UTC DateTime to Unix
Parse an ISO or UTC date string and get Unix seconds. Runs in your browser.
Live Unix Timestamp
Current Unix time in seconds and milliseconds, updating live. Copy with one click.
Seconds to H:M:S
Convert total seconds into hours, minutes, and seconds. No upload.
Duration Between Two DateTimes
Paste two ISO date-times (one per line) and get the difference in days, hours, and total seconds.
Parse ISO 8601 Duration
Parse PT1H30M style durations into total seconds and parts.
Random Time Generator
Pick a random clock time between two HH:mm values. Useful for testing.
Countdown to DateTime
Enter a target date-time; see time remaining until then.
Current UTC Time
Live clock showing current UTC date and time. Updates every second.
ISO 8601 Normalizer
Parse a date string and output normalized UTC ISO 8601.
ISO Week Number
ISO-8601 week number and year for a given date.
Business Days Between
Approximate weekdays Mon–Fri between two dates (excluding weekends).
Random DateTime in Range
Random ISO date-time between two bounds (inclusive).
Milliseconds ↔ Unix Seconds
Convert between Unix seconds and milliseconds. Bidirectional.
Time Ago
How long ago was this Unix timestamp or ISO date?
Add Duration to DateTime
Start date-time plus days, hours, minutes offset.
H:M:S to Total Seconds
Parse durations like 1:30:45 or 90:00 into total seconds.
Seconds to Human Duration
Turn large second counts into days, hours, minutes (e.g. 90061 → 1d 1h 1m).
Same Instant: Seconds & Milliseconds
Enter Unix seconds or ms; see the paired value for the same instant.
Unix to Local DateTime
Convert Unix time to your browser locale string plus ISO. Client-side only.
Unix to UTC ISO String
Minimal output: ISO 8601 in UTC from Unix input.
Build ISO 8601 Duration
Combine days, hours, minutes into a PnDTnHnM style duration string.
RFC 3339 Date Validator
Check if a string is a valid RFC 3339 / ISO date-time and show normalized UTC.
Calendar Days Between Dates
Two lines: start and end date (ISO or parseable). Get whole calendar days between.
Subtract Duration from DateTime
Start date-time minus days, hours, minutes.
Day of Year
From a date, get the 1–366 day-of-year number.
Leap Year Checker
Enter a year (or full date) and see if it is a leap year.
Days in Month
How many days in a given month and year.
Quarter of Year
Get Q1–Q4 for a given date.
Weekday Name
English weekday name from a date string.
Month Name
Full English month name from a date.
Relative Time Phrases
Use Intl to express a date relative to now (e.g. in 2 days). Paste ISO or Unix.
Random Unix Timestamp in Range
Random integer Unix seconds between min and max.
Age from Birth Date
Approximate age in years from a birth date.
Start of UTC Day
Given a date, get UTC midnight as ISO and Unix seconds.
End of UTC Day
Last millisecond of the UTC day for a given calendar date.
Compare Two Timestamps
Two Unix values: which is earlier and by how many seconds.
Unix to RFC 1123
HTTP-style date from Unix seconds (GMT).
Decimal Minutes to H:M:S
Convert 90.5 minutes into hours, minutes, seconds.
Add Seconds to Unix Time
Base Unix timestamp plus or minus N seconds.
Browser Time Zone Offset
Show your current IANA-style offset from UTC (from the browser).
ISO Date to Unix Milliseconds
Parse ISO string and output Unix ms and seconds.
Monday of Week (UTC)
Given a date, the UTC date of the Monday starting that ISO week.
First Instant of Month (UTC)
UTC start of month for year-month input.
Last Instant of Month (UTC)
Last millisecond of the month in UTC.
Seconds Since Midnight UTC
For a given instant, seconds elapsed since UTC midnight that day.
Ordinal Day Suffix
Turn day of month into 1st, 2nd, 3rd, 4th style.
Tomorrow’s Date (UTC)
Calendar date of tomorrow in UTC from today or optional base date.
Yesterday’s Date (UTC)
Calendar date of yesterday in UTC.
Round Unix to Hour
Floor Unix seconds to the start of that UTC hour.
Frequently Asked Questions
- What are Date & Time Tools tools?
- Date & Time Tools tools are free online utilities that run in your browser. They help developers and content creators work faster—no installation, no account, and your data stays on your device. Use any tool instantly from desktop or mobile.
- Are Date & Time Tools tools free?
- Yes. All Date & Time Tools tools on everytools are completely free. No signup, no subscription, no limits. Use them as often as you need.
- How do I use Date & Time Tools tools?
- Open any tool on this page, paste or enter your input in the field, and view the result. Most tools update in real time. Click Copy to copy output to your clipboard. All processing happens in your browser—your data never leaves your device.
- Do I need to install anything for Date & Time Tools tools?
- No. All Date & Time Tools tools run in your web browser. No downloads, no plugins, no installation. Works on desktop and mobile.