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10101010 in Decimal

Binary 10101010 equals 170 in decimal.

Why this number matters: 170 is 0xAA / binary 10101010 - the classic alternating bit pattern used in memory tests.

10101010 in all number bases

Decimal170
Hexadecimal0xAA
Binary1010 1010
Octal252

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Edit this value or switch its base. Your changes are calculated in your browser with exact integer arithmetic.

Input base:
Decimal170
Hex0xAA
Binary0b10101010
Octal0o252

How 10101010 converts from binary to decimal

Multiply each digit by 2 raised to its position (starting at 0 from the right), then add the results:

1× 27 = 1 × 128 = 128
0× 26 = 0 × 64 = 0
1× 25 = 1 × 32 = 32
0× 24 = 0 × 16 = 0
1× 23 = 1 × 8 = 8
0× 22 = 0 × 4 = 0
1× 21 = 1 × 2 = 2
0× 20 = 0 × 1 = 0

Sum: 170

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Want to learn the method behind this tool? Read How to Convert Binary to Decimal - the full step-by-step guide.