Hex to Decimal Converter

Q: What is FF in decimal?

FF in hex is 255 in decimal: 15 × 16 + 15 = 255. It is the largest value one byte can hold. Read as a signed 8-bit number (two's complement), the same bits mean −1.

Q: How do I convert a negative hex number to decimal?

If the hex number has a minus sign, convert the digits and keep the sign: −1A = −26. If it is a two's-complement value such as FFFE , tick Signed (two's complement) and choose 16-bit: the converter subtracts 2¹⁶ = 65536 from 65534 and shows −2.

Q: Can I convert hex numbers with a fractional part?

Yes. Digits after the point are worth 16⁻¹ = 1/16, 16⁻² = 1/256 and so on, so 1A.8 = 26 + 8/16 = 26.5 and 0.4 = 0.25.

Q: Is there a limit on the size of the hex number?

No practical limit. The converter uses arbitrary-precision integers, so 64-bit values such as FFFFFFFFFFFFFFFF (18446744073709551615) and even longer hex strings are converted exactly, without rounding.

Type a hexadecimal number such as FF or 0x1A and see its decimal value instantly, with the calculation shown step by step. The converter also gives binary and octal, reads signed (two's complement) and fractional values and converts whole lists at once.

From

Number to convert

Tip: enter one number per line to convert a whole list.

Signed (two's complement)

Bit width

Group digits Lowercase a–f

In all bases

Hexadecimal
Decimal
Binary
Octal

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How to use the hex to decimal converter

Type or paste a hex number into the input box. Prefixes such as 0x or #, a trailing h, spaces and underscores are all accepted. Enter one number per line to convert a list.
The decimal value appears instantly, together with the binary and octal values and a step-by-step explanation of the calculation.
If the hex value is a signed integer, tick Signed (two's complement) and pick the bit width – for example FF is −1 as an 8-bit number. Then copy the result.

How to convert hex to decimal

Hexadecimal is a base-16 number system. It uses the digits 0–9 and the letters A = 10, B = 11, C = 12, D = 13, E = 14 and F = 15. Each position is worth 16 times more than the one to its right, so the hex to decimal conversion formula is:

decimal = dₙ × 16ⁿ + … + d₂ × 16² + d₁ × 16¹ + d₀ × 16⁰

Multiply every digit by the power of 16 for its position, counting from 0 on the right, and add the results. Example: 3C = 3 × 16 + 12 = 60, and 1A3F = 1 × 4096 + 10 × 256 + 3 × 16 + 15 × 1 = 4096 + 2560 + 48 + 15 = 6719.

Position	Power of 16	Decimal value
0	16⁰	1
1	16¹	16
2	16²	256
3	16³	4096
4	16⁴	65536
5	16⁵	1048576

Hex to decimal table

The hex values people look up most often, with their decimal equivalents. One byte ranges from 00 to FF (0–255); the notes show the ASCII character or what the value means in programming.

Hex	Decimal	Good to know
`10`	16	16¹
`1A`	26	1 × 16 + 10
`20`	32	ASCII space
`2A`	42	ASCII `*`
`3C`	60	ASCII `<`
`64`	100	ASCII `d`
`7F`	127	Largest signed 8-bit value
`80`	128	−128 as a signed byte
`FF`	255	Largest byte value; −1 as a signed byte
`100`	256	16²
`3E8`	1000	3 × 256 + 14 × 16 + 8
`7FFF`	32767	Largest signed 16-bit value
`FFFF`	65535	Largest 16-bit value; −1 as a signed 16-bit number
`7FFFFFFF`	2147483647	Largest signed 32-bit integer
`FFFFFFFF`	4294967295	Largest unsigned 32-bit integer

Hex to decimal in Python, JavaScript and Excel

Python: int('1A', 16) returns 26; the 0x prefix is allowed too: int('0xff', 16) = 255.
JavaScript: parseInt('1A', 16) or Number('0x1A'). For values above 2⁵³ use BigInt('0x' + hex) to avoid rounding.
Excel and Google Sheets: =HEX2DEC("1A"). Excel reads 10-digit values as signed 40-bit numbers, so =HEX2DEC("FFFFFFFFFF") returns −1.
Java, C# and C: Integer.parseInt("1A", 16), Convert.ToInt32("1A", 16) and strtol("1A", NULL, 16).
Linux and macOS shell: echo $((16#1A)) or printf '%d\n' 0x1A.

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Frequently asked questions

What is FF in decimal?

FF in hex is 255 in decimal: 15 × 16 + 15 = 255. It is the largest value one byte can hold. Read as a signed 8-bit number (two's complement), the same bits mean −1.

How do I convert a negative hex number to decimal?

If the hex number has a minus sign, convert the digits and keep the sign: −1A = −26. If it is a two's-complement value such as FFFE, tick Signed (two's complement) and choose 16-bit: the converter subtracts 2¹⁶ = 65536 from 65534 and shows −2.

Can I convert hex numbers with a fractional part?

Yes. Digits after the point are worth 16⁻¹ = 1/16, 16⁻² = 1/256 and so on, so 1A.8 = 26 + 8/16 = 26.5 and 0.4 = 0.25.

Is there a limit on the size of the hex number?

No practical limit. The converter uses arbitrary-precision integers, so 64-bit values such as FFFFFFFFFFFFFFFF (18446744073709551615) and even longer hex strings are converted exactly, without rounding.