Decimal (base 10)
Decimal (base 10) is the everyday number system, using the digits 0 through 9. It is the default base for almost all human-facing numbers — from prices to phone numbers to scientific measurements.
Decimal to Hexadecimal Converter
255 (dec) = FF (hex)
Convert decimal numbers to hexadecimal numbers exactly, for any size. Convertitive parses your input as a BigInt — so 64-bit values, 256-bit hex strings, and even larger numbers round-trip without rounding. For quick reference: 255 dec = FF hex, and 1024 dec = 400 hex.
Quick
How to convert decimal numbers to hexadecimal numbers
Enter a value
Type a decimal integer in the From field. Allowed characters: 0 through 9.
Read the hexadecimal result
The To field updates as you type. For example, the decimal value 255 equals FF in hexadecimal.
Copy or share
Use the copy button to grab the result. You can change either base from its dropdown without leaving the page.
Reference table
Fifty representative values. Every row is computed exactly by the same BigInt-based converter that powers the widget above.
| Decimal (dec) | Hexadecimal (hex) |
|---|---|
| 0 | 0 |
| 1 | 1 |
| 2 | 2 |
| 3 | 3 |
| 4 | 4 |
| 5 | 5 |
| 6 | 6 |
| 7 | 7 |
| 8 | 8 |
| 9 | 9 |
| 10 | A |
| 11 | B |
| 12 | C |
| 13 | D |
| 14 | E |
| 15 | F |
| 16 | 10 |
| 17 | 11 |
| 18 | 12 |
| 19 | 13 |
| 20 | 14 |
| 24 | 18 |
| 31 | 1F |
| 32 | 20 |
| 36 | 24 |
| 42 | 2A |
| 48 | 30 |
| 50 | 32 |
| 63 | 3F |
| 64 | 40 |
| 100 | 64 |
| 127 | 7F |
| 128 | 80 |
| 200 | C8 |
| 255 | FF |
| 256 | 100 |
| 500 | 1F4 |
| 511 | 1FF |
| 512 | 200 |
| 1000 | 3E8 |
| 1023 | 3FF |
| 1024 | 400 |
| 2048 | 800 |
| 4096 | 1000 |
| 8192 | 2000 |
| 16384 | 4000 |
| 32768 | 8000 |
| 65535 | FFFF |
| 65536 | 10000 |
| 1048576 | 100000 |
Frequently asked questions
- How do I convert decimal numbers to hexadecimal numbers?
- Enter your decimal value above. Convertitive parses it as an arbitrary-precision integer and reformats it in hexadecimal. The conversion is exact for any size — there's no float rounding.
- What is 255 in hexadecimal?
- 255 (decimal) equals FF in hexadecimal.
- Are negative numbers supported?
- Yes, with decimal. Two's-complement representations for fixed-width binary/hex are not supported here — the converter treats negative as a sign on the absolute value.
- What's the largest number I can convert?
- Any size. Convertitive uses JavaScript BigInt, which has no fixed upper bound — 256-bit hex strings, 512-bit and bigger all round-trip exactly.
- How many bits does the result take?
- An n-digit number in base 10 needs roughly 3.32 × n bits to store. The exact bit length equals ⌈log₂(value + 1)⌉.
- Is hex case-sensitive?
- No. You can type hex with letters in either case. Output is always uppercase (A–F).
- Are conversion factors exact?
- Yes. Base conversion is integer-to-integer; there are no factors, no rounding, no precision loss.
- Why would I convert decimal numbers to hexadecimal numbers?
- Hex is the standard compact notation for binary data — memory addresses, color codes, hashes. Converting from decimal to hex packs the same value into a more readable form.
About decimal and hexadecimal
Hexadecimal (base 16)
Hexadecimal (base 16) uses digits 0–9 plus the letters A–F to encode the values 10–15. It is the dominant compact notation for binary data: every two hex digits represent exactly one byte. Used universally for memory addresses, color codes (#RRGGBB), and cryptographic hashes.