Convert 281 475 098 388 840 to a Signed Binary in Two's (2's) Complement Representation

How to convert decimal number 281 475 098 388 840(10) to a signed binary in two's (2's) complement representation

What are the steps to convert decimal number
281 475 098 388 840 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;
  • 281 475 098 388 840 ÷ 2 = 140 737 549 194 420 + 0;
  • 140 737 549 194 420 ÷ 2 = 70 368 774 597 210 + 0;
  • 70 368 774 597 210 ÷ 2 = 35 184 387 298 605 + 0;
  • 35 184 387 298 605 ÷ 2 = 17 592 193 649 302 + 1;
  • 17 592 193 649 302 ÷ 2 = 8 796 096 824 651 + 0;
  • 8 796 096 824 651 ÷ 2 = 4 398 048 412 325 + 1;
  • 4 398 048 412 325 ÷ 2 = 2 199 024 206 162 + 1;
  • 2 199 024 206 162 ÷ 2 = 1 099 512 103 081 + 0;
  • 1 099 512 103 081 ÷ 2 = 549 756 051 540 + 1;
  • 549 756 051 540 ÷ 2 = 274 878 025 770 + 0;
  • 274 878 025 770 ÷ 2 = 137 439 012 885 + 0;
  • 137 439 012 885 ÷ 2 = 68 719 506 442 + 1;
  • 68 719 506 442 ÷ 2 = 34 359 753 221 + 0;
  • 34 359 753 221 ÷ 2 = 17 179 876 610 + 1;
  • 17 179 876 610 ÷ 2 = 8 589 938 305 + 0;
  • 8 589 938 305 ÷ 2 = 4 294 969 152 + 1;
  • 4 294 969 152 ÷ 2 = 2 147 484 576 + 0;
  • 2 147 484 576 ÷ 2 = 1 073 742 288 + 0;
  • 1 073 742 288 ÷ 2 = 536 871 144 + 0;
  • 536 871 144 ÷ 2 = 268 435 572 + 0;
  • 268 435 572 ÷ 2 = 134 217 786 + 0;
  • 134 217 786 ÷ 2 = 67 108 893 + 0;
  • 67 108 893 ÷ 2 = 33 554 446 + 1;
  • 33 554 446 ÷ 2 = 16 777 223 + 0;
  • 16 777 223 ÷ 2 = 8 388 611 + 1;
  • 8 388 611 ÷ 2 = 4 194 305 + 1;
  • 4 194 305 ÷ 2 = 2 097 152 + 1;
  • 2 097 152 ÷ 2 = 1 048 576 + 0;
  • 1 048 576 ÷ 2 = 524 288 + 0;
  • 524 288 ÷ 2 = 262 144 + 0;
  • 262 144 ÷ 2 = 131 072 + 0;
  • 131 072 ÷ 2 = 65 536 + 0;
  • 65 536 ÷ 2 = 32 768 + 0;
  • 32 768 ÷ 2 = 16 384 + 0;
  • 16 384 ÷ 2 = 8 192 + 0;
  • 8 192 ÷ 2 = 4 096 + 0;
  • 4 096 ÷ 2 = 2 048 + 0;
  • 2 048 ÷ 2 = 1 024 + 0;
  • 1 024 ÷ 2 = 512 + 0;
  • 512 ÷ 2 = 256 + 0;
  • 256 ÷ 2 = 128 + 0;
  • 128 ÷ 2 = 64 + 0;
  • 64 ÷ 2 = 32 + 0;
  • 32 ÷ 2 = 16 + 0;
  • 16 ÷ 2 = 8 + 0;
  • 8 ÷ 2 = 4 + 0;
  • 4 ÷ 2 = 2 + 0;
  • 2 ÷ 2 = 1 + 0;
  • 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.

281 475 098 388 840(10) = 1 0000 0000 0000 0000 0000 0111 0100 0000 1010 1001 0110 1000(2)

3. Determine the signed binary number bit length:

  • The base 2 number's actual length, in bits: 49.

  • 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, 49,

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 281 475 098 388 840(10) converted to signed binary in two's complement representation:

281 475 098 388 840(10) = 0000 0000 0000 0001 0000 0000 0000 0000 0000 0111 0100 0000 1010 1001 0110 1000

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