Math
Hex to Decimal Converter
Type a hex number (0-9, A-F) and get its decimal value with the place-value table: each digit times 16 to its position.
The panel also splits the value into 4-bit nibbles and can read the pattern as a signed two's complement number.
Digits 0-9 and A-F (either case). A hex point is allowed (F.8). A 0x prefix is fine.
Choose two's complement when the leftmost bit is a sign bit.
Try an example
Result
Converted value
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- Decimal
- —
- Binary
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- Hexadecimal
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- Octal
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Study path
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What the hex to decimal converter solves
Hexadecimal (base 16) uses the digits 0-9 and the letters A-F for 10-15. Each place is worth 16 times the place to its right, so 1A3F = 1×4096 + 10×256 + 3×16 + 15×1 = 6719. This converter shows that expansion for any hex number, including fractional hex and signed patterns.
Hex digit values
| Hex | 0 | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | A | B | C | D | E | F |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Decimal | 0 | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 |
| Binary | 0000 | 0001 | 0010 | 0011 | 0100 | 0101 | 0110 | 0111 | 1000 | 1001 | 1010 | 1011 | 1100 | 1101 | 1110 | 1111 |
How to use it
- Enter the hex number in either case; a 0x prefix is fine.
- Choose Unsigned for a plain value or Signed two's complement with a bit width when the top bit is a sign bit (for example a signed byte FB).
- Read the place-value table: each row is a digit, its value, its weight (a power of 16), and their product; the products add to the decimal answer.
How to read the answer
The decimal value is the main result. The nibble table shows the same number in binary four bits at a time, which is the fastest way to move between hex and binary. In signed mode, a leading hex digit of 8-F at the chosen width means the value is negative.
Common mistakes and edge cases
- Treating letters as their alphabet position: A is 10, not 1; F is 15.
- Typing G or beyond. Hex stops at F, and the converter names the offending character.
- Reading 10 (hex) as ten. It is sixteen; hex 0A is ten.
- A leading 0x or # (as in CSS colors) is a prefix, not a digit. 0x is accepted; drop a # before converting.
- Signed hex depends on width: FF is 255 unsigned, −1 as an 8-bit signed value, and 255 as a 16-bit signed value.
Worked examples
Typical hex
1A3F
Converted value
6,719
Byte maximum
FF
Converted value
255
Signed byte
FB as 8-bit two's complement
Converted value
-5
Hex fraction
F.8
Converted value
15.5
Zero
0x0
Converted value
0
Large value
FFFFFFFFFFFFFFFF
Converted value
18,446,744,073,709,551,615
Invalid digit
1G
Converted value
—
Frequently asked questions
How do you convert hex to decimal?+
Replace each letter with its value (A=10 … F=15), multiply each digit by 16 raised to its position counting from 0 on the right, and add. 2F = 2×16 + 15 = 47.
What is FF in decimal?+
FF = 15×16 + 15 = 255, the largest value of one byte. As an 8-bit signed number it is −1.
Why is hex used for colors and memory addresses?+
One hex digit is exactly four bits, so a byte is two hex digits. Colors like #1A3FFF are three bytes, and addresses are easier to read in hex than in long binary strings.
Can hex have a fractional part?+
Yes. Digits after the point are worth 1/16, 1/256, and so on. F.8 = 15 + 8/16 = 15.5.
Is hex case sensitive?+
No. 1a3f and 1A3F are the same value. The converter shows results in uppercase.
About this calculator
- Written by
- mathcheck editorial team
- Last reviewed
- September 4, 2026
Method
- Uses the values entered by the user and stable formulas documented on the page.
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Last updated: September 4, 2026