# Decimal to Hexadecimal Calculator

Convert decimal to hexadecimal and back. Also shows binary and octal. Essential for programmers working with colors, memory addresses, and byte values.

## What this calculates

Convert between decimal and hexadecimal number systems instantly. This calculator also shows binary and octal representations, plus the programmer-friendly 0x prefix format. Essential for web development, system programming, and digital electronics.

## Inputs

- **Conversion Mode** — options: Decimal → Hexadecimal, Hexadecimal → Decimal
- **Decimal Number** — min 0, max 2147483647 — Non-negative integer (used in Dec → Hex mode).
- **Hexadecimal String** — min 0 — Enter the hex digits as a number (e.g., 255 for FF). Used in Hex → Dec mode.

## Outputs

- **Hexadecimal** — formatted as text — The number in hexadecimal (base 16).
- **Decimal** — formatted as text — The number in decimal (base 10).
- **Binary** — formatted as text — The number in binary (base 2).
- **Octal** — formatted as text — The number in octal (base 8).
- **Hex (0x prefix)** — formatted as text — Hexadecimal with the standard 0x programming prefix.

## Details

Hexadecimal (base 16) is the most common shorthand for binary data in computing. Each hex digit represents exactly 4 bits, so a byte (8 bits) is always exactly 2 hex digits. That compact mapping is why hex is everywhere in programming.

How the Conversion Works

To convert decimal to hex, repeatedly divide by 16 and record the remainders. Map remainders 10-15 to A-F.

Example: 255 / 16 = 15 remainder 15. 15 in hex = F. So 255 = FF.

Common Decimal to Hex Values

Decimal
Hex
Binary
Usage

0
0
0
Zero

10
A
1010
First hex letter

15
F
1111
Max single hex digit

16
10
10000
Two hex digits start

127
7F
1111111
Max signed byte

255
FF
11111111
Max byte value

256
100
100000000
Three hex digits start

65535
FFFF
1111111111111111
Max 2-byte value

16777215
FFFFFF
...
Max 3-byte (white in RGB)

In web development, CSS hex colors like #FF5733 are three hex byte pairs: FF (red = 255), 57 (green = 87), 33 (blue = 51).

## Frequently Asked Questions

**Q: How do I convert decimal to hexadecimal?**

A: Divide the decimal number by 16 repeatedly. Write down each remainder. Map remainders 10-15 to letters A-F. Read the remainders from last to first. Example: 200 / 16 = 12 R8. 12 in hex is C. So 200 decimal = C8 hex.

**Q: What do the letters A through F mean in hexadecimal?**

A: Hexadecimal needs 16 symbols, but we only have 10 digit characters (0-9). Letters A through F represent the values 10 through 15. A=10, B=11, C=12, D=13, E=14, F=15.

**Q: Why do programmers use hexadecimal instead of decimal?**

A: Each hexadecimal digit maps to exactly 4 binary digits. This makes hex a compact, human-readable way to represent binary data. One byte is always exactly 2 hex digits (00 to FF). In decimal, a byte ranges from 0 to 255, which is harder to align with binary boundaries.

**Q: What does the 0x prefix mean?**

A: The 0x prefix is a convention in programming languages like C, JavaScript, Python, and Java to indicate that the following digits are hexadecimal, not decimal. For example, 0xFF means 255 in decimal, not the number "FF."

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Source: https://vastcalc.com/calculators/technology/decimal-to-hexadecimal
Category: Technology
Last updated: 2026-04-21