Home Tools About Us ♥ Support Us
🔢 Base Converter

Any base,
any batch, instantly

Binary, octal, decimal, hex, and unlimited custom bases — bulk text, files, and ZIPs, all converted in your browser.

Results

Output Bases

Toggle the built-in bases and add as many custom base columns as you like.

OnBaseHeaderFixed Length (0 = off)

Formatting

🕘 Local History

Saved only on this device — never uploaded anywhere. Click an entry to reload it.

No history yet. Convert something above to see it appear here.

How to use every option

  1. Choose a source — type/paste numbers (one per line) in Type/Paste mode, or switch to File/ZIP Upload to drop in .txt files or a .zip containing several .txt files.
  2. Set the "From base" — pick Binary/Octal/Decimal/Hex, a custom base, or Auto-detect, which reads0x,0b, and0o prefixes and defaults to decimal otherwise.
  3. Pick output bases — toggle Binary/Octal/Decimal/Hex on or off in the Output Bases table, and click "+ Add Custom Base Column" for any base from 2 to 9999, with its own header label.
  4. Digit mode — "Letters" shows 10+ as a,b,c… up to base 36, then falls back to numeric for anything higher. "Always numeric" shows every digit as a number separated by your chosen separator — useful for very large custom bases.
  5. Padding vs Fixed Length — turn on auto-padding to line up every value in a column to the longest one automatically, or set a specific "Fixed Length" per column and choose whether short values pad at the start or end, and whether long values truncate at the start, truncate at the end, or get flagged as an exception.
  6. Enclosures — wrap every result in matching or different left/right characters using a preset or your own custom text.
  7. Digit grouping — set a group size (e.g. 4) and separator to break long values into readable chunks, like1010 1100.
  8. Search — type in the search box to filter and highlight matching values across both the input list and the results table.
  9. Convert, then copy all results, or export as .txt/.csv/.json — check "ZIP output" to get one output file per uploaded file group, bundled into a single ZIP with your chosen filename.
  10. Fraction Converter tab — for decimal numbers with a fractional part (e.g. 10.375), converts both the integer and fractional portions to any base at your chosen precision.
  11. Local History — every conversion you run is saved to this device only; click any entry to reload those exact settings.

Built to replace every base-conversion tool you'd normally juggle

🔢
Unlimited Custom Bases
Binary, octal, decimal, hex, plus any base from 2 to 9999, each with its own header and settings.
📄
Bulk & File Conversion
Paste hundreds of lines, or upload multiple .txt files and even a .zip of files at once.
📦
ZIP Export
Download every result as one file, or as a ZIP with one output file per uploaded group.
🧱
Padding & Fixed Length
Auto-align columns, or set an exact width with pad/truncate/exception behavior.
🔤
Letters or Numeric Digits
Auto letter digits up to base 36, or always-numeric digits for very large custom bases.
🕘
Local History
Every conversion is saved to your browser only, one click to reload.

Frequently Asked Questions

Binary (2), Octal (8), Decimal (10), and Hexadecimal (16) by default, plus any custom base from 2 to 9999 that you add yourself.

By default, digit values 10 and above are shown as letters (a, b, c…) up to base 36. Past base 36, or if you switch to Numeric Digit Mode, each digit is shown as a plain number separated by your chosen separator.

Yes. Paste one number per line in the input box, or upload one or more text files, and every line is converted in a single pass.

Yes. Upload a .zip and every .txt file inside it is extracted and converted as its own group, entirely in your browser.

Padding automatically pads every value in a column with leading zeros to match the longest value in that column. Fixed length lets you set an exact width per column, choosing whether shorter values pad at the start or end, and whether longer values truncate at the start, truncate at the end, or are flagged as an exception.

Yes. Pick a preset like parentheses or brackets, or type any custom left and right enclosure text — they don't have to match.

No. All parsing, conversion, and file/ZIP handling happens locally in your browser. Nothing is sent to or stored on our servers.

Yes, a leading minus sign is preserved through conversion. For binary output you can also enable a fixed bit width with two's complement representation.

Yes. The search box filters and highlights matching rows in both the input list and the results table, in text and file modes.

Related tools

Browse Other Categories

Support EaseDev Studios

All tools are free. If they've saved you time, consider supporting us.

Buy Us a Coffee

A quick one-time gesture that means a lot.

Buy a Coffee →
🎗️

Become a Patron

Support us monthly and help build more tools.

Join on Patreon →