221 octal to binary

Here we will show you how to convert the octal number 221 to a binary number. First note that the octal number system has eight different digits (0 1 2 3 4 5 6 7) and the binary number system has only two different digits (0 and 1).

The four steps used to convert 221 from octal to binary are explained below.

Step 1)
Multiply the last digit in 221 by 8⁰, multiply the second to last digit in 221 by 8¹, multiply the third to last digit in 221 by 8², multiply the fourth to last digit in 221 by 8³, and so on, until all the digits are used:

1 × 8⁰ = 1
2 × 8¹ = 16
2 × 8² = 128

Step 2)
Next, we add up all the products we got from Step 1, like this:

1 + 16 + 128 = 145

Step 3)
Now we divide the sum from Step 2 by 2. Put the remainder aside. Then divide the whole part by 2 again, and put the remainder aside again. Keep doing this until the whole part is 0.

145 ÷ 2 = 72 with 1 remainder
72 ÷ 2 = 36 with 0 remainder
36 ÷ 2 = 18 with 0 remainder
18 ÷ 2 = 9 with 0 remainder
9 ÷ 2 = 4 with 1 remainder
4 ÷ 2 = 2 with 0 remainder
2 ÷ 2 = 1 with 0 remainder
1 ÷ 2 = 0 with 1 remainder

Step 4)
In the final step, we take the remainders from Step 3 and put them together in reverse order to get our answer to 221 octal to binary:

221 octal = 10010001 binary

Octal to Binary Converter
Here you can convert another octal number to binary. Remember, octal numbers only include digits 0 through 7.

222 octal to binary
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