Date, Time & Number Formatting
Convert Unix timestamps, build date format patterns, convert time zones and durations, and format numbers with separators, currency and Indian lakh/crore grouping. Every tool shows its result live as you type and gives you the code to produce the same output in JavaScript, Python, Java or SQL.
Common tasks
About date & number tools
Dates and numbers are presentation problems. The value is the same whether it reads 1790409600, 2026-09-26T08:00:00Z or Saturday, 26 September 2026 — what changes is the shape a person or a system expects. Formattr’s date tools parse what you paste, echo back how they understood it in ISO 8601 so there is no ambiguity, and then show it in every common format at once.
The Date Formatter includes a pattern builder with clickable tokens and catches the most common real-world bug — using YYYY (week-numbering year) where yyyy (calendar year) was meant. The Timestamp Converter detects seconds, milliseconds, microseconds and nanoseconds from the digit count and shows a live current-epoch ticker.
Number formatting uses your browser’s Intl API, so every locale, currency and notation it supports is available, including en-IN grouping that writes 12,34,567 instead of 1,234,567.
Frequently asked questions
Which time zone is used?
Your browser’s time zone by default. Every date tool lets you choose any IANA time zone, and conversions account for daylight saving time.
How do you tell seconds from milliseconds?
By digit count: 10 digits are seconds, 13 milliseconds, 16 microseconds and 19 nanoseconds for dates between 2001 and 2286. You can override the unit.
Can I get code for the same format?
Yes. The Date Formatter and Number Formatter generate the equivalent code for JavaScript, Python, Java and SQL from the same pattern or options, so the output you see is the output your program will produce.
Is 03/04/2026 March 4 or 3 April?
It is ambiguous, so Formattr shows a toggle to choose how to read it instead of guessing silently.
More categories
- Data Formatters & ConvertersFormat, validate and convert the data and configuration formats developers handle every day: JSON, YAML, XML, CSV, TOML and .env files. Every tool here keeps the same information and changes only its structure — pretty-printed for reading, minified for shipping, or converted for the next system. Everything runs in your browser, so API responses and customer records never leave your machine.
- Code FormattersFormat JavaScript, TypeScript, HTML, CSS, Markdown and more with the same engines your editor uses — Prettier, clang-format, gofmt and Ruff — without installing anything. Paste minified or messy code, get consistently formatted output, and minify it again when you need to ship. Code never leaves your browser.