What is 1001 in decimal?

1001₂ converted to decimal is 9₁₀. The place-value working for these exact bits is below — or try other bits in the binary to decimal converter.

1001₂ = 9₁₀

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Binary₂ (from)

Only 0–1. Type here — the answer appears instantly, no button to press.

Decimal₁₀ (to)

Quinary₅

Octal₈

Hexadecimal₁₆

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Give each bit its place value — 1, 2, 4, 8 and so on, doubling from the right — then add up the places where the bit is 1.

Bit	Position	Place value	Bit × place
1	3	8	8
0	2	4	0
0	1	2	0
1	0	1	1

Add the last column: 8 + 1 = 9. So 1001₂ = 9₁₀.

In short: 1001₂: 1×8 = 8 → +0×4 = 8 → +0×2 = 8 → +1×1 = 9

How do you convert 1001 to decimal?

Use place values. The 1 bits sit at place values 8, 1, and 8 + 1 = 9. So 1001₂ = 9₁₀.

What is 1001 in hexadecimal?

1001₂ is 9₁₆. Group the bits in fours from the right and read each group as one hex digit — or check the 9₁₀ = 9₁₆ conversion in the boxes above.