Decimal to Hexadecimal Converter

The divide-by-16 method

Divide the decimal number by 16 and write down the remainder. Convert any remainder of 10–15 to its letter (10→A, 11→B, 12→C, 13→D, 14→E, 15→F). Replace the number with the quotient and repeat until you reach 0, then read the remainders from bottom to top. Here is 700:

700 ÷ 16 = 43  remainder 12 → C
 43 ÷ 16 =  2  remainder 11 → B
  2 ÷ 16 =  0  remainder  2 → 2
read upward → 2BC

So 700 in decimal is 2BC in hexadecimal. Check it back: 2×256 + 11×16 + 12 = 512 + 176 + 12 = 700.

The via-binary shortcut

Because one hex digit equals exactly four binary bits (a nibble), many people convert decimal to binary first, split the bits into groups of four from the right, and read each group as one hex digit. For 700 → binary 1010111100 → padded 0010 1011 1100 → 2 B C. This is handy when you are already comfortable with binary or when you need both representations at once, which the converter shows side by side.

Reference table

Padding matters in practice: a color channel of decimal 5 should be written 05, not 5, so each byte stays two characters. The converter's grouping and uppercase options make these byte-aligned codes easy to copy.

Where you'll use it

• Building CSS and design hex colors from RGB values (e.g. 30, 144, 255 → 1E90FF).
• Writing byte constants and register values in C, assembly and embedded code.
• Formatting Unicode code points as U+XXXX.
• Producing compact identifiers and checksums for logs and configs.

Negative numbers

For signed values, choose a bit width and the converter outputs the two's complement hex. For example, −1 in 8-bit becomes FF, in 16-bit FFFF and in 32-bit FFFFFFFF — the all-ones pattern that represents −1 at every width.