Convert decimal to hexadecimal and hex to decimal. Step-by-step division method, CSS color preview, ASCII table, and common hex values reference.
Hexadecimal (base 16) is the language of programmers and web designers. From memory addresses and color codes to MAC addresses and byte values, hex numbers appear everywhere in computing. This converter provides instant bidirectional conversion between familiar decimal (base 10) numbers and their hexadecimal equivalents, with all intermediate bases shown.
The step-by-step division method shows exactly how decimal-to-hex conversion works: repeatedly divide by 16 and read the remainders. For web developers, the built-in CSS color preview automatically interprets 6-digit hex values as RGB colors with a live swatch. The tool also includes a comprehensive common values reference and a scrollable ASCII table mapping characters to their hex codes.
Whether you are a web designer working with hex color codes, a programmer reading memory dumps, a student learning number systems, or troubleshooting network configurations, this converter gives you instant results with educational context. The preset values cover the most commonly needed conversions including byte boundaries and popular color codes.
Manual hex conversion via the division method works but is tedious for large numbers. This tool converts instantly, shows the step-by-step work, previews colors for 6-digit hex values, and includes ASCII and common-value references — a complete hex toolkit in one page for students, developers, designers, and technical support workflows.
Decimal to Hex (division method): Repeatedly divide by 16, record remainders, read bottom-up. Hex to Decimal (positional): Sum of (digit_value × 16^position) for each digit. Example: 0xFF = 15×16¹ + 15×16⁰ = 240 + 15 = 255
Result: 0xFF
255 ÷ 16 = 15 R 15. 15 ÷ 16 = 0 R 15. Remainders from bottom to top: 15, 15 = F, F. Result: 0xFF. This is the maximum value of an unsigned 8-bit byte (1111 1111 in binary).
Hex is a perfect compromise between human readability and binary representation. Each hex digit maps to exactly 4 bits. Two hex digits represent one byte. This makes it compact yet easy to mentally convert to binary. A 32-bit memory address like 0x7FFF0000 is far more readable than 01111111111111110000000000000000 in binary or 2,147,418,112 in decimal.
CSS colors use the #RRGGBB format where each component is a hex byte (00-FF = 0-255). #000000 is black, #FFFFFF is white, #FF0000 is pure red. Shorthand #RGB expands each digit: #F00 = #FF0000. Newer CSS supports #RRGGBBAA with alpha transparency (00 = transparent, FF = opaque).
ASCII maps characters to numbers 0-127. Printable characters span 0x20 (space) to 0x7E (tilde). Capital letters start at 0x41 (A), lowercase at 0x61 (a), digits at 0x30 (0). The uppercase-lowercase difference is exactly 0x20 (bit 5), which is why toggling case is a single bit operation.
Divide the number by 16 repeatedly. Write down the remainder at each step. When the quotient reaches 0, read the remainders from last to first. Convert remainders 10-15 to A-F.
CSS colors use 3 bytes (one for red, green, blue), with each byte ranging 0-255. Two hex digits perfectly represent one byte (00-FF), making #RRGGBB a compact 6-character notation for 16.7 million colors.
0xFF is the programming notation (C, JavaScript, Python) for hex. #FF is used in CSS/HTML color codes. Both represent the hex value FF = 255 decimal. The prefix varies by context but the value is identical.
FF = 255 in decimal (11111111 in binary). With 4 hex digits: FFFF = 65,535. With 8 hex digits: FFFFFFFF = 4,294,967,295 (max 32-bit unsigned integer).
Memory addresses and values are displayed in hex. Group hex digits from right in pairs to see individual bytes. For example, 0x0040102A is 4 bytes: 00, 40, 10, 2A.
Hex can represent fractional values in floating-point notation (e.g., 0x1.8p+0 = 1.5). Negative numbers use two's complement: -1 in 32-bit hex is 0xFFFFFFFF.