How do I convert decimal to hexadecimal manually?

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.

Why do color codes use hexadecimal?

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.

What is the difference between 0xFF and #FF?

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.

What is the largest number in 2 hex digits?

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).

How do I read hex in a debugger?

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.

Can hexadecimal represent fractions or negative numbers?

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.

Decimal to Hexadecimal Converter

Convert decimal to hexadecimal and hex to decimal. Step-by-step division method, CSS color preview, ASCII table, and common hex values reference.

Direction

Decimal Number

Decimal

255

Hexadecimal

0xFF

1 byte(s)

Binary

1111 1111

8 bits

Octal

0o377

Base 8

CSS Hex Color

#0000FF

Enter 6 hex digits for color

Bytes

8 bits needed

Division Method (Decimal → Hex)

Step	Dividend ÷ 16	Quotient	Remainder	Hex Digit
1	255 ÷ 16	15	15	F
2	15 ÷ 16	0	15	F

Read hex digits from bottom to top: 0xFF

Common Decimal-Hex Values

Decimal	Hex	Binary	Meaning
0	0x00	0000 0000	Null / zero
10	0x0A	0000 1010	Newline (LF)
13	0x0D	0000 1101	Carriage return (CR)
32	0x20	0010 0000	Space character
65	0x41	0100 0001	ASCII "A"
127	0x7F	0111 1111	DEL / max 7-bit
255	0xFF	1111 1111	Max unsigned byte
256	0x100	1 0000 0000	First 2-byte value
1,024	0x400	100 0000 0000	1 KB (binary)
65,535	0xFFFF	1111 1111 1111 1111	Max unsigned 16-bit

Planning notes, formulas, and examples

About the Decimal to Hexadecimal Converter

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. It gives 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 the conversion with educational context. The preset values cover the most commonly needed conversions including byte boundaries and popular color codes.

When This Page Helps

Manual hex conversion via the division method works but is tedious for large numbers. This converter 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.

How to Use the Inputs

Choose the conversion direction: Decimal → Hexadecimal or Hexadecimal → Decimal.
Enter your number in the input field (# prefix is automatically stripped for hex).
View the result in all four bases: decimal, hex, binary, and octal.
For values under 1,000,000, see the Division Method step-by-step.
If the hex value is 6 digits, a CSS color preview appears automatically.
Expand the ASCII Table reference for character-to-hex mapping.

Formula used

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

Example Calculation

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).

Tips & Best Practices

Hex digits: 0-9 are the same as decimal, A=10, B=11, C=12, D=13, E=14, F=15.
CSS color codes: #RRGGBB where each pair is a hex byte (00-FF = 0-255).
Quick byte check: if hex has 1-2 digits, it fits in 1 byte. 3-4 digits = 2 bytes. 5-6 digits = 3 bytes.
ASCII printable characters span 0x20 (space) to 0x7E (tilde ~).
A hex color where all pairs match (#FF5733) has R=255, G=87, B=51 — a vivid orange-red.
To convert hex to decimal quickly: each hex digit has a place value of 16^position, rightmost is 16^0.

Why Hexadecimal Dominates Computing

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.

Hex Color Codes for Web Design

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).

The ASCII Connection

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.

Sources & Methodology

Last updated: March 8, 2026

Frequently Asked Questions

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.