How to Convert Decimal to Hex: A Step-by-Step Guide

To convert a decimal number to hexadecimal, divide the number by 16 repeatedly and read the remainders from bottom to top, mapping 10–15 to the letters A–F. With the ByteTools Decimal to Hex converter you skip the arithmetic entirely: type the base-10 value and the exact hex result appears instantly, in your browser. This guide walks through both the manual method and the fastest way to get a code-ready result.

Hexadecimal (base 16) is the shorthand engineers use for bytes, memory addresses and color codes because every 4 bits map cleanly to one hex digit. Knowing how to move from base 10 to base 16 is a core skill for anyone reading a hex dump or writing a CSS color.

The manual method, explained

Converting by hand uses repeated division by 16. Each remainder becomes one hex digit, and you collect them from last to first:

1. Divide your decimal number by 16 and note the whole quotient and the remainder.
2. Convert any remainder of 10–15 to its letter: 10=A, 11=B, 12=C, 13=D, 14=E, 15=F.
3. Repeat with the quotient until it reaches 0.
4. Read the remainders from the last one to the first — that string is your hexadecimal value.

For example, 700 ÷ 16 = 43 remainder 12 (C); 43 ÷ 16 = 2 remainder 11 (B); 2 ÷ 16 = 0 remainder 2. Reading upward gives 2BC. It works, but it is slow and error-prone for large values — which is exactly where a tool helps.

The fast way: use the converter

The ByteTools converter does the division for you and formats the output to match your target. The steps take seconds:

1. Type or paste your decimal (base-10) number into the input box.
2. Toggle Uppercase to switch between FF and ff.
3. Toggle the 0x prefix if you want output like 0x2BC that drops straight into code.
4. Read the hexadecimal result as it updates live, then copy it with one click.

Common conversions at a glance

Decimal	Hex	With 0x prefix
10	A	0xA
16	10	0x10
255	FF	0xFF
4096	1000	0x1000
65535	FFFF	0xFFFF

Why BigInt and privacy matter

Ordinary JavaScript loses precision above 2^53, so naive converters silently corrupt large 64-bit values. This tool uses BigInt, meaning a huge counter, snowflake ID or memory address converts exactly with no rounding. Negative integers are supported too, and invalid input shows a clear error instead of a misleading answer. Because everything runs 100% locally in your browser, nothing you type is uploaded, logged or stored — and the tool keeps working offline once loaded.

Try the Decimal to Hex converter — free and 100% in your browser.

FAQ

How do I read the remainders in the right order?

Collect them from the last division to the first. The final remainder you calculate is the most significant (leftmost) hex digit, and the first remainder is the rightmost digit.

Do I need the 0x prefix?

Only when the format requires it. Many languages use 0x to mark a hex literal in source code, while CSS colors, documentation and hex dumps usually omit it. The toggle lets you produce either form.

What happens if I paste a decimal with a fraction?

The converter expects whole integers, so a value with a decimal point is flagged as invalid input. Round or truncate to a whole number first, then convert.

Is uppercase or lowercase hex correct?

Both are equally valid — FF and ff represent the same value. Lowercase is conventional in CSS and web colors; uppercase is common in assembly listings and documentation.

Related free tools

• Hex to Decimal — convert the other direction.
• Decimal to Binary — base 10 to base 2.
• Binary to Decimal — read binary as a number.
• HEX to RGB Converter — turn a hex color into RGB values.

Built by ByteVancer

ByteTools is a free product of ByteVancer, a software and web development studio that builds web apps, SaaS platforms and custom software. If you need engineering help beyond a quick converter, explore what ByteVancer can build for your team.