Tools tagged "time"

Enter a birth date and a reference date to get the full age in years, days lived, Eastern zodiac (12 animals), and Western zodiac. Change the reference date to compute the age at any past or future point. Everything runs inside your browser — your birthday never leaves the page.

Type a start date (relationship, wedding, business launch, fan-club anniversary) and instantly see the elapsed time as 『Y years M months D days』, weeks, days, hours, minutes, and seconds. Upcoming milestones (100, 200, 1000 days, 1/5/10 year marks…) are computed with their own countdowns. Updates every second; copy any value in one click. Where age-calc is birthday-specific, this tool fits any anniversary. Everything runs in your browser.

Compute the date that is N business days before or after a given date, skipping Chinese public holidays (New Year, Spring Festival, Qingming, Labour Day, Dragon Boat, Mid-Autumn, National Day) and weekends. Honours 调休 (makeup work-days) — weekends officially designated as working days to bridge long holidays. Data follows the State Council's published 2024 and 2025 schedules; 2026 is an approximation pending official notice. Runs entirely in your browser.

Compute the date that is N business days before or after a given date, skipping Japanese national holidays plus weekends. Handles substitute holidays, citizen's holidays, and vernal/autumnal equinoxes (1955-2099). Useful for due dates, settlement dates, and Japan-side delivery scheduling. Runs entirely in your browser.

Compute the date that is N business days before or after a given date, skipping the 11 US federal holidays (New Year's, MLK Day, Presidents' Day, Memorial Day, Juneteenth, Independence Day, Labor Day, Columbus Day, Veterans Day, Thanksgiving, Christmas) and weekends. Saturday-fall holidays observed Friday and Sunday-fall observed Monday, per federal employee rules. Juneteenth recognised from 2021; MLK Day from 1986. Runs entirely in your browser.

For any date, see all four common **week-numbering systems** side by side: **ISO 8601** (Monday start, week-of-Jan-4 = W01); **US** (Sunday start, week-of-Jan-1 = W01); **Middle East** (Saturday start, ISO-style anchor); **Simple** (Jan 1 = Day 1, then every 7 days). Useful for sprint planning across SaaS tools (Linear / Jira week-of-year), or for debugging the classic "W21 means different dates in Berlin and Boston" problem. Scroll through months and hover the calendar to see how each system numbers the weeks; year-boundary edge cases show clearly. Sister tool to `iso-week` (single ISO conversion); this tool focuses on **comparison and calendar visualisation**. Runs entirely in your browser.

Real-time display of the remaining time until (countdown) or the elapsed time since (count-up) a target date. Days / hours / minutes / seconds tick every second. Copy the URL to share the current setup (?to=datetime&mode=countdown). Uses your browser's local timezone. Runs entirely in your browser — the target datetime never leaves your device.

List the next 10–100 firing times for a cron expression like `0 9 * * 1-5`. Validate your crontab / GitHub Actions / Kubernetes CronJob / Vercel Cron Jobs schedules before deploying. Powered by cron-parser running entirely in your browser.

Compute the gap between two dates in days, weeks, business days, a years-months-days breakdown, and (optionally) hours/minutes/seconds. Toggle inclusivity and time-of-day with a checkbox. Everything runs inside your browser.

Type a date format pattern like `YYYY-MM-DD` or `%Y-%m-%d` and the tool formats the current time (or any reference datetime) on the fly. Switch between **dayjs / Moment.js** and **strftime** (C / Python / PHP) styles, browse 10 presets (ISO 8601, RFC 3339, RFC 2822, JP, US, log line, etc.), and reference the full token cheatsheet without leaving the page.

Convert durations between three formats: seconds (5400), clock (01:30:00), and human-readable (1h30m). Pick the output format and the input is auto-detected — even mixed formats on different lines. Bulk-converts multi-line input and reports skipped (unparseable) lines. Supports d/h/m/s units (1d = 86400 seconds). Runs entirely in your browser.

Convert between Gregorian years and Japanese eras (Meiji, Taishō, Shōwa, Heisei, Reiwa) with a mode toggle. Accepts year-only or full date input, handles 元年 (year 1) and era-boundary transitions like 2019-05-01 → Reiwa 1 (令和元年). No dictionary download required — runs entirely inside your browser.

From your last meal time and a chosen fasting protocol — 12:12, 14:10, 16:8, 18:6, 20:4 (Warrior), 23:1 (OMAD), 36h extended, or custom — the tool shows when the fast ends and the next eating window opens / closes. A 24-hour heat-map visualises 'fasting' vs 'eating' hours. Built for Leangains, OMAD, and 5:2 practitioners.

A browser-only interval timer for HIIT (High-Intensity Interval Training) and Tabata (20 s work / 10 s rest × 8 rounds). Configure warm-up, work, rest, cool-down and rounds in seconds, with the current phase / remaining time / round progress shown live. Settings autosave to localStorage. Phase transitions trigger short Web Audio beeps (work start = high 880 Hz, rest start = low 440 Hz, finished = chord), and the final 3 seconds add an optional countdown tick. One-click presets: Tabata (20/10 × 8), HIIT 30/30, HIIT 45/15, HIIT 40/20. Uses `performance.now()` deltas so transitions stay accurate in throttled background tabs. Timer logic and audio all run inside your browser — nothing is uploaded.

Convert between ISO 8601 week numbers (e.g. 2026-W21-6) and calendar dates (e.g. 2026-05-23). Pick the output format with a mode toggle. Week-only input (2026-W21) is parsed as the Monday of that week. Follows ISO rules: W01 is the week containing 4 Jan, weeks start on Monday, and year-boundary cases (2024-12-30 = 2025-W01-1) are handled correctly. Runs entirely in your browser.

Convert between historical Japanese eras (645 Taika through 1868 Keiō) and Gregorian years in both directions. Built-in dataset of 240+ pre-Meiji eras, including 元年 (year 1) and the rival Northern/Southern court eras of the Nanboku-chō schism (1331–1392). For Meiji onward use the era-convert tool. Year-level precision (the lunisolar calendar makes month/day mapping ambiguous). Runs entirely inside your browser — no dictionary download required.

Check whether a given year is a leap year under the Gregorian rule (divisible by 4 ∧ (not by 100 ∨ by 400)). The result shows which rule applied, the year's day count (365 or 366), the position within the 4-year cycle (Year mod 4), and the 10 leap years immediately before and after. February 29 birthdays also get a 'next birthday' calculation. Useful for clearing up classic calendar misconceptions (why 1900 isn't a leap year, why 2000 is). Runs entirely in your browser.

Calculate the moon age, phase (new / first quarter / full / last quarter) and illuminated fraction for any date and time, shown as a moon diagram. Also finds the next new, first-quarter, full, and last-quarter moments. A mean synodic-month approximation that runs entirely in your browser.

Pick a target datetime and a base datetime (defaults to *now*), and `Intl.RelativeTimeFormat` returns localized strings like `3 hours ago`, `in 2 weeks`, `yesterday`, or `3 ヶ月後` — exactly the format GitHub uses for `2 days ago`, Slack uses for `3h`, or Twitter uses for `5m`. Output is rendered **side-by-side in ja and en**, with toggles for style (long / short / narrow) and numeric (always / auto). A breakdown table shows the value across **all seven scales** (year / month / week / day / hour / minute / second), useful when designing the threshold logic for an `agoString()` helper. Compared with `date-diff` (numeric breakdown) and `duration-format` (elapsed-seconds formatter), this tool focuses on natural-language relative phrasing. Nothing is uploaded.

Look up the Rokuyō (六曜) of any date — Sensho / Tomobiki / Senbu / Butsumetsu / Taian / Shakkō — and view a full month at a glance. Rokuyō is the traditional 6-day cycle used in Japan for picking auspicious days for weddings, funerals, moves, and store openings. Lunar conversion uses solarlunar (ISC); Rokuyō is computed as (lunar month + lunar day) mod 6. Includes month navigation and a per-Rokuyō meaning (Taian = all-day lucky, Butsumetsu = all-day unlucky, Tomobiki = 'pulls a friend' so funerals are avoided, etc.). Covers 1900-2099. Everything runs in your browser; no date information is uploaded.