Convert 111 011 101 289 to a Signed Binary in Two's (2's) Complement Representation

How to convert decimal number 111 011 101 289(10) to a signed binary in two's (2's) complement representation

What are the steps to convert decimal number
111 011 101 289 to a signed binary in two's (2's) complement representation?

  • A signed integer, written in base ten, or a decimal system number, is a number written using the digits 0 through 9 and the sign, which can be positive (+) or negative (-). If positive, the sign is usually not written. A number written in base two, or binary, is a number written using only the digits 0 and 1.

1. Divide the number repeatedly by 2:

Keep track of each remainder.

We stop when we get a quotient that is equal to zero.


  • division = quotient + remainder;
  • 111 011 101 289 ÷ 2 = 55 505 550 644 + 1;
  • 55 505 550 644 ÷ 2 = 27 752 775 322 + 0;
  • 27 752 775 322 ÷ 2 = 13 876 387 661 + 0;
  • 13 876 387 661 ÷ 2 = 6 938 193 830 + 1;
  • 6 938 193 830 ÷ 2 = 3 469 096 915 + 0;
  • 3 469 096 915 ÷ 2 = 1 734 548 457 + 1;
  • 1 734 548 457 ÷ 2 = 867 274 228 + 1;
  • 867 274 228 ÷ 2 = 433 637 114 + 0;
  • 433 637 114 ÷ 2 = 216 818 557 + 0;
  • 216 818 557 ÷ 2 = 108 409 278 + 1;
  • 108 409 278 ÷ 2 = 54 204 639 + 0;
  • 54 204 639 ÷ 2 = 27 102 319 + 1;
  • 27 102 319 ÷ 2 = 13 551 159 + 1;
  • 13 551 159 ÷ 2 = 6 775 579 + 1;
  • 6 775 579 ÷ 2 = 3 387 789 + 1;
  • 3 387 789 ÷ 2 = 1 693 894 + 1;
  • 1 693 894 ÷ 2 = 846 947 + 0;
  • 846 947 ÷ 2 = 423 473 + 1;
  • 423 473 ÷ 2 = 211 736 + 1;
  • 211 736 ÷ 2 = 105 868 + 0;
  • 105 868 ÷ 2 = 52 934 + 0;
  • 52 934 ÷ 2 = 26 467 + 0;
  • 26 467 ÷ 2 = 13 233 + 1;
  • 13 233 ÷ 2 = 6 616 + 1;
  • 6 616 ÷ 2 = 3 308 + 0;
  • 3 308 ÷ 2 = 1 654 + 0;
  • 1 654 ÷ 2 = 827 + 0;
  • 827 ÷ 2 = 413 + 1;
  • 413 ÷ 2 = 206 + 1;
  • 206 ÷ 2 = 103 + 0;
  • 103 ÷ 2 = 51 + 1;
  • 51 ÷ 2 = 25 + 1;
  • 25 ÷ 2 = 12 + 1;
  • 12 ÷ 2 = 6 + 0;
  • 6 ÷ 2 = 3 + 0;
  • 3 ÷ 2 = 1 + 1;
  • 1 ÷ 2 = 0 + 1;

2. Construct the base 2 representation of the positive number:

Take all the remainders starting from the bottom of the list constructed above.

111 011 101 289(10) = 1 1001 1101 1000 1100 0110 1111 1010 0110 1001(2)

3. Determine the signed binary number bit length:

  • The base 2 number's actual length, in bits: 37.

  • A signed binary's bit length must be equal to a power of 2, as of:
  • 21 = 2; 22 = 4; 23 = 8; 24 = 16; 25 = 32; 26 = 64; ...
  • The first bit (the leftmost) indicates the sign:
  • 0 = positive integer number, 1 = negative integer number

The least number that is:


1) a power of 2

2) and is larger than the actual length, 37,

3) so that the first bit (leftmost) could be zero
(we deal with a positive number at this moment)


=== is: 64.


4. Get the positive binary computer representation on 64 bits (8 Bytes):

If needed, add extra 0s in front (to the left) of the base 2 number, up to the required length, 64.


Decimal Number 111 011 101 289(10) converted to signed binary in two's complement representation:

111 011 101 289(10) = 0000 0000 0000 0000 0000 0000 0001 1001 1101 1000 1100 0110 1111 1010 0110 1001

Spaces were used to group digits: for binary, by 4, for decimal, by 3.


How to convert signed integers from decimal system to signed binary in two's complement representation

Follow the steps below to convert a signed base 10 integer number to signed binary in two's complement representation:

  • 1. If the number to be converted is negative, start with the positive version of the number.
  • 2. Divide repeatedly by 2 the positive representation of the integer number, keeping track of each remainder, until we get a quotient that is zero.
  • 3. Construct the base 2 representation of the positive number, by taking all the remainders starting from the bottom of the list constructed above. Thus, the last remainder of the divisions becomes the first symbol (the leftmost) of the base two number, while the first remainder becomes the last symbol (the rightmost).
  • 4. Binary numbers represented in computer language must have 4, 8, 16, 32, 64, ... bit length (a power of 2) - if needed, add extra bits on 0 in front (to the left) of the base 2 number above, up to the required length, so that the first bit (the leftmost) will be 0, correctly representing a positive number.
  • 5. To get the negative integer number representation in signed binary one's complement, replace all 0 bits with 1s and all 1 bits with 0s (reversing the digits).
  • 6. To get the negative integer number, in signed binary two's complement representation, add 1 to the number above.

Example: convert the negative number -60 from the decimal system (base ten) to signed binary in two's complement:

  • 1. Start with the positive version of the number: |-60| = 60
  • 2. Divide repeatedly 60 by 2, keeping track of each remainder:
    • division = quotient + remainder
    • 60 ÷ 2 = 30 + 0
    • 30 ÷ 2 = 15 + 0
    • 15 ÷ 2 = 7 + 1
    • 7 ÷ 2 = 3 + 1
    • 3 ÷ 2 = 1 + 1
    • 1 ÷ 2 = 0 + 1
  • 3. Construct the base 2 representation of the positive number, by taking all the remainders starting from the bottom of the list constructed above:
    60(10) = 11 1100(2)
  • 4. Bit length of base 2 representation number is 6, so the positive binary computer representation of a signed binary will take in this particular case 8 bits (the least power of 2 larger than 6) - add extra 0 digits in front of the base 2 number, up to the required length:
    60(10) = 0011 1100(2)
  • 5. To get the negative integer number representation in signed binary one's complement, replace all the 0 bits with 1s and all 1 bits with 0s (reversing the digits):
    !(0011 1100) = 1100 0011
  • 6. To get the negative integer number, signed binary in two's complement representation, add 1 to the number above:
    -60(10) = 1100 0011 + 1 = 1100 0100
  • Number -60(10), signed integer, converted from decimal system (base 10) to signed binary two's complement representation = 1100 0100