Hex Calculator
Convert hexadecimal (base 16) to decimal, binary, and octal, or convert any number into hex. Also supports base conversions between any bases from 2 to 36.
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How It Works
Hex has 16 digits: 0,1,2,3,4,5,6,7,8,9,A,B,C,D,E,F. After 9, use letters: A=10, B=11, C=12, D=13, E=14, F=15.
0-9, A(10), B(11), C(12), D(13), E(14), F(15)FF: F=15, so FF = 15×16 + 15 = 255Multiply each digit by 16^position. Rightmost is 16⁰=1, next is 16¹=16, then 16²=256, etc. Sum all products.
Sum of (digit × 16^position)2A: 2×16+10×1 = 32+10 = 42Divide by 16, record remainders. If remainder ≥ 10, replace with letter. Read remainders bottom to top.
Divide by 16, collect remainders42: 42/16=2 R10(A) → 2AEach hex digit maps to exactly 4 binary bits. Convert each hex digit independently to 4-bit binary and concatenate.
1 hex digit = 4 bitsFA: F=1111, A=1010 → 11111010CSS colors #RRGGBB use two hex digits per channel. Each pair 00-FF represents intensity 0-255 for Red, Green, Blue.
#RRGGBB = 3 hex pairs#FF5733: R=255, G=87, B=51Memory addresses in computing are written in hex. 0x7FFFFFFF is a 32-bit address. The 0x prefix indicates hex.
0x prefix for hex in code0xFF = 255, 0x100 = 256Quick Reference
Common examples — verify instantly above.
Hex→Dec
FF
255
Hex→Dec
2A
42
Hex→Dec
1F4
500
Dec→Hex
255
FF
Dec→Hex
42
2A
Dec→Hex
256
100
Hex→Bin
FA
11111010
Color
#FF0000
R=255,G=0,B=0
Tips & Shortcuts
Memorize: A=10, B=11, C=12, D=13, E=14, F=15. These are the only new symbols in hex.
Each hex digit = 4 binary bits. FF = 1111 1111 = 255. This makes hex a perfect shorthand for binary.
Web colors use hex: #FFFFFF = white, #000000 = black, #FF0000 = red, #00FF00 = green, #0000FF = blue.
A byte is 8 bits = 2 hex digits = values 00 to FF (0-255). This is why image channels use 256 values.
The prefix 0x in code means hex: 0xFF = 255, 0x1A = 26. Some code uses # or h prefix instead.
Hex 10 = decimal 16, hex 100 = decimal 256, hex 1000 = decimal 4096. Powers of 16.
Common Mistakes
Reading hex F as 0 or ignoring it
F is a valid digit equal to 15. Never skip or zero-out letter digits.
Multiplying by 10 instead of 16 when converting
Hex is base 16, not 10. Position values are 1, 16, 256, 4096... not 1, 10, 100, 1000.
Grouping binary in 3s instead of 4s for hex conversion
Hex requires groups of 4 bits. Octal uses groups of 3. Use 4-bit groups when converting to hex.
Forgetting the 0x prefix in code
When writing hex values in code (C, Python, JavaScript), prefix with 0x. 255 ≠ 0xFF without the prefix.
Treating hex letters as case-sensitive
Hex digits are not case-sensitive. 0xFF = 0XFF = 0xff. All are equivalent.
Confusing hex color channels
In #RRGGBB, first pair is Red, second Green, third Blue. #FF0000 is red, not blue.
Frequently Asked Questions
Hexadecimal is base 16. Digits are 0-9 and A-F, where A=10, B=11, C=12, D=13, E=14, F=15.
Hex is a compact representation of binary. Each hex digit equals exactly 4 binary bits, making it easy to read memory addresses and color codes.
#FF0000 is an RGB color: R=FF=255, G=00=0, B=00=0 → pure red in decimal RGB (255, 0, 0).
Multiply each digit by 16^position and sum. FF = 15×16¹ + 15×16⁰ = 240+15 = 255.
FF = 255 in decimal. One hex byte (2 digits) ranges from 00 to FF (0 to 255).
#RRGGBB where each pair is a hex value 00-FF. #FFFFFF=white, #000000=black, #FF5500=orange.
A hex color like #FF5733 has three pairs: FF (red), 57 (green), 33 (blue). Each pair is a hex byte (00 to FF), representing 0–255 in decimal. FF = 255 (maximum intensity), 00 = 0 (none). So #FF5733 = RGB(255, 87, 51) — maximum red, medium-low green, low blue = orange-red. #000000 is black (all zero). #FFFFFF is white (all maximum). #808080 is 50% gray (128,128,128).
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