Number Base Converter

How to use Number Base Converter

1. Type an integer into Number, or press Try an example. With Input base on Auto, 0x, 0b and 0o prefixes pick hex, binary or octal and anything else is decimal. Choose Bin, Oct, Dec, Hex or Other (bases 2–36) to force a base.
2. Read the value in binary, octal, decimal and hex, plus any base from 2 to 36 in the As row. Group digits and Uppercase change how the output is written.
3. Check Two’s complement for the 8, 16, 32 and 64-bit signed and unsigned forms, and whether the number fits each width.
4. Under IEEE-754 floating point, enter a decimal value (or inf, NaN) or switch Float input to Hex bits to decode raw bits, and pick float32 or float64 to see the sign, exponent, mantissa and exact stored value.
5. Use the Bitwise calculator to combine A and B with AND, OR, XOR, NAND, NOR, NOT, shifts and rotations at a chosen Width, and Characters and codes to turn text into code points and UTF-8 bytes or codes back into text.

How it works

Integers are parsed digit by digit into JavaScript BigInt, so there is no size limit and large values are never rounded. Spaces, underscores, commas and apostrophes are ignored as group separators, a leading + or - sets the sign, and in Hex mode a leading # is also accepted. Invalid digits are reported with their position.

Two’s complement uses BigInt.asIntN and BigInt.asUintN to wrap the value to each width. A number “fits” if it is within the signed minimum and the unsigned maximum of that width. The bitwise calculator wraps both operands to the selected width the same way, so the result is always shown as both unsigned and signed.

Float bits are read and written with a DataView, exactly as the computer stores them. The stored value is expanded to its full exact decimal, which shows, for example, that 0.1 is really 0.1000000000000000055511151231257827021181583404541015625 in float64. Characters are read as Unicode code points and encoded with TextEncoder for the UTF-8 bytes.

Limits

• Only integers are converted between bases; fractions aren’t supported there. Use the IEEE-754 section for fractional values.
• Two’s complement is shown for 8, 16, 32 and 64 bits. The bitwise calculator offers 8, 16, 32, 64 and 128 bits, and shift and rotate amounts must be between 0 and 100,000.
• In Hex bits mode the value must fit the chosen width: up to 8 hex digits for float32 and 16 for float64.
• Text → codes lists the first 500 characters. Codes → text accepts decimal, 0x… or …h hex, U+…, \u… and 0b…, separated by spaces, commas or semicolons; values outside 0–0x10FFFF and lone surrogates are rejected.

Privacy

Everything runs in your browser with built-in JavaScript. Nothing you enter is uploaded or saved. Copy share link puts your inputs and settings from every section in the link’s # fragment, which browsers don’t send to servers, so anyone you give the link to can see them.

Frequently asked questions

Is there a limit on how big a number can be?

No fixed limit. Numbers are handled as arbitrary-precision integers (BigInt), so a 100-digit decimal converts exactly. Very long inputs just take longer to display.

How do I enter a negative number in hex or binary?

Put a minus sign in front, for example -0xff. The conversions show it with a minus sign, and the two’s complement section shows the bit pattern a computer would store, such as 0xFF01 for 16 bits.

Why is 0.1 not exactly 0.1?

Binary floating point can’t represent most decimal fractions exactly, so the nearest representable value is stored. The Stored value row shows that value in full.

What does “overflows, wrapped” mean?

The number doesn’t fit in that many bits, signed or unsigned. The bits shown are the lowest ones, which is what a fixed-width integer would keep after overflowing.

What is the difference between >>> and >>?

A >>> B (logical) shifts in zeros from the left. A >> B (arithmetic) copies the sign bit, so negative numbers stay negative. Both work within the selected Width.