Find the ISO week number for any date. Also shows the day of the week and the current week of the year.
Add or subtract days from any date. Get the resulting date instantly — useful for deadlines, scheduling, and planning.
Check when daylight saving time starts and ends in the US for any year. Shows the exact dates and DST period length.
Calculate the time elapsed between any date and now. Shows results in years, months, weeks, days, hours, minutes, and seconds.
Calculate the day number of the year for any date. Find out which day of 365 (or 366) a specific date represents.
Find out what day of the week any date falls on. Look up birthdays, holidays, historical events, and future dates.
Week Number Calculator lets you find the ISO week number for any date. Also shows the day of the week and the current week of the year.. Everything runs inside your browser — nothing is uploaded to a server. It works on any device with a modern web browser.
Find the ISO week number for any date. Also shows the day of the week and the current week of the year. It's ideal for developers, designers, and anyone who needs to find the iso week number for any date without installing software or sending data to external servers.
Direct text entry, file upload, or URL-based input — depending on the tool. All numeric values are entered through input fields with real-time updates.
Yes. After the initial page load, Week Number Calculator runs entirely on your device with no internet connection needed. All processing is done locally.
Tools cover JavaScript, CSS, HTML, SQL, Python, JSON, XML, CSV, and more. Check individual tool descriptions for specifics.
No. All code processing — formatting, minification, conversion, hashing — runs locally in your browser.
Yes. Since processing is local, performance depends on your device. Most operations handle large files without issue.
Yes. SQL uses sql-formatter, JSON uses native JSON.parse, and other formatters follow widely adopted formatting rules.
Yes. All developer tools work fully offline after the initial page load.
Time Converter
Convert between time units including seconds, minutes, hours, days, weeks, months, and years with precise decimal results.
Diff Checker
Compares two input texts side-by-side, highlighting inserted, deleted, and changed lines with distinct background colors.
Regex Tester
Provides an interactive environment where users can write a regular expression pattern, test it against sample strings, and view real-time match.
JSON Formatter
Pretty-prints raw JSON with configurable indent width, key sorting, and bracket collapsing options while flagging syntax errors with exact.
JS Minifier
Strips comments, whitespace, and shortens local variable names in JavaScript source without altering execution semantics.
Base64 Encode/Decode
Encodes text or small files into Base64 strings and decodes them back with automatic MIME-type detection for binary safety.