Number Base (Radix) Converter
Decimal to Binary Converter
Convert base-10 decimal numbers to base-2 binary representation with bit grouping.
Number Base (Radix)
(DEC)
Example: 255 DEC
(BIN)
e.g. 1111 1111BIN
Standard: Base 2 (1 bit = binary digit)
Enter any number above to convert Decimal to Binary. Click (i) for brief unit info.
Converting the other way?
Switch directly to the reverse calculator: Binary to Decimal Converter
How to Convert Decimal (Base 10) to Binary (Base 2)
Official Mathematical Formula
Binary = successive division by 2
Where the input value in DEC is transformed using the exact standardized conversion factor to produce the output in BIN.
Practical Calculation Example
You can verify this calculation directly using our interactive tool above.
Quick Conversion Reference Table (DEC → BIN)
Decimal (Base 10) (DEC) | Binary (Base 2) (BIN) | Copy |
|---|---|---|
| 1 DEC | 1 BIN | |
| 2 DEC | 10 BIN | |
| 3 DEC | 11 BIN | |
| 5 DEC | 101 BIN | |
| 10 DEC | 1010 BIN | |
| 15 DEC | 1111 BIN | |
| 20 DEC | 1 0100 BIN | |
| 25 DEC | 1 1001 BIN | |
| 50 DEC | 11 0010 BIN | |
| 75 DEC | 100 1011 BIN | |
| 100 DEC | 110 0100 BIN | |
| 250 DEC | 1111 1010 BIN | |
| 500 DEC | 1 1111 0100 BIN | |
| 1000 DEC | 11 1110 1000 BIN |
Related Number Base (Radix) Calculators
All Number Base (Radix) Tools →Decimal (Base 10) to Binary (Base 2) FAQs
Divide by 2, write down the remainder (0 or 1), and repeat with the quotient until reaching 0. Read remainders from bottom to top.