Convert numbers between any base
Type a value in binary, octal, decimal, hex or any base up to 36. See all four common representations side-by-side with BigInt support for arbitrarily large integers.
How base conversion works
BigInt parses 0b, 0o and 0x prefixes natively. We strip them, normalize input to a BigInt, then call toString(2/8/10/16) for each form.
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Pick input base
The dropdown tells the parser how to read your digits.
Parsing is strict-but-tolerant — comments and trailing commas are accepted on input where the source format historically permits them; output stays canonical.
basestricttolerantliveparsebase · sourcepick · livebase 16
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Paste digits
Leading 0x / 0o / 0b are tolerated.
Conversion preserves type information where the target supports it (numbers stay numeric, booleans stay boolean) so the destination parser never has to re-coerce.
digitstype-preservinglosslesslivememoisedin · optionsdigits · live0xFF
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BigInt parse
Arbitrary-precision — no JS Number overflow.
Re-encoding is idempotent: running output back through the same converter produces the same bytes, which keeps round-trips git-friendly.
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Render forms
toString(2/8/10/16) for every output.
Copy writes via
navigator.clipboard.writeText; downloads use the target’s native MIME so editors apply the right syntax highlighting on open.outclipboardtarget MIMEblobclient-side✓ · copiedready · done11111111
shipped · ready to shipsuccess
Converting between formats, safely
Pick the strictest source format
Lossy formats hide bugs. Choose JSON or YAML as your source-of-truth, convert downstream as needed.
Round-trip in CI
If your converter is idempotent, your CI can verify A → B → A equals the original. Catches subtle data loss.
Numbers vs strings differ
YAML/TOML have a number type; CSV doesn’t. Quote IDs in CSV to keep leading-zero values intact.
Watch character encoding
Source format may be Latin-1 / Windows-1252; target should be UTF-8. Convert encoding before structure.
Preserve comments where you can
YAML and TOML support comments. Don’t silently drop them — they often encode intent.
Schema-aware beats blind
Use a schema to guide conversion. Field types, required-ness, and defaults survive better with structure.
When to convert bases
Networking, embedded, bit-twiddling.
Networking
Convert IP octets between dec and hex. Type information survives: numbers stay numeric, booleans stay boolean, strings stay strings. The destination parser doesn't have to re-coerce, which avoids the "'true' becomes "true"" bug class.
round-trip safeEmbedded
Flip register values between bin and hex. Run output back through the inverse converter to verify idempotent round-trips in CI. A → B → A should produce byte-identical input — if it doesn't, you've found data loss.
type-preservingBit masks
Visualize flag combinations as binary. Comments and metadata survive where the target format supports them (YAML, TOML, HCL). The tool doesn't silently drop intent-encoded annotations, which keeps your config self-documenting.
schema-awareCrypto inspection
Read hex key material in decimal for math. Pair with a schema (JSON Schema, OpenAPI, Zod, Pydantic) to catch shape drift on either side. Catch breaking changes at conversion time rather than at runtime in production.
losslessUnicode codepoints
U+1F600 as decimal for character APIs. Output respects target-format conventions: quoting in CSV, indent in YAML, brackets in JSON. Existing parsers don't need patches, and the result drops into legacy pipelines unchanged.
i18nWeb colors
Hex #RRGGBB to decimal RGB triples. Encoding-aware: handles UTF-8 vs UTF-16 vs Latin-1 / Windows-1252 transparently. The character-set surprise that breaks "works on my machine" doesn't apply here.
spec-gradeFrequently asked questions
Something missing?
Tell us what you need. We ship the top requests every two weeks.