Convert -281 470 681 808 880 to a Signed Binary (Base 2)

How to convert -281 470 681 808 880(10), a signed base 10 integer number? How to write it as a signed binary code in base 2

What are the required steps to convert base 10 integer
number -281 470 681 808 880 to signed binary code (in base 2)?

  • 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. Start with the positive version of the number:

|-281 470 681 808 880| = 281 470 681 808 880

2. Divide the number repeatedly by 2:

Keep track of each remainder.

Stop when you get a quotient that is equal to zero.


  • division = quotient + remainder;
  • 281 470 681 808 880 ÷ 2 = 140 735 340 904 440 + 0;
  • 140 735 340 904 440 ÷ 2 = 70 367 670 452 220 + 0;
  • 70 367 670 452 220 ÷ 2 = 35 183 835 226 110 + 0;
  • 35 183 835 226 110 ÷ 2 = 17 591 917 613 055 + 0;
  • 17 591 917 613 055 ÷ 2 = 8 795 958 806 527 + 1;
  • 8 795 958 806 527 ÷ 2 = 4 397 979 403 263 + 1;
  • 4 397 979 403 263 ÷ 2 = 2 198 989 701 631 + 1;
  • 2 198 989 701 631 ÷ 2 = 1 099 494 850 815 + 1;
  • 1 099 494 850 815 ÷ 2 = 549 747 425 407 + 1;
  • 549 747 425 407 ÷ 2 = 274 873 712 703 + 1;
  • 274 873 712 703 ÷ 2 = 137 436 856 351 + 1;
  • 137 436 856 351 ÷ 2 = 68 718 428 175 + 1;
  • 68 718 428 175 ÷ 2 = 34 359 214 087 + 1;
  • 34 359 214 087 ÷ 2 = 17 179 607 043 + 1;
  • 17 179 607 043 ÷ 2 = 8 589 803 521 + 1;
  • 8 589 803 521 ÷ 2 = 4 294 901 760 + 1;
  • 4 294 901 760 ÷ 2 = 2 147 450 880 + 0;
  • 2 147 450 880 ÷ 2 = 1 073 725 440 + 0;
  • 1 073 725 440 ÷ 2 = 536 862 720 + 0;
  • 536 862 720 ÷ 2 = 268 431 360 + 0;
  • 268 431 360 ÷ 2 = 134 215 680 + 0;
  • 134 215 680 ÷ 2 = 67 107 840 + 0;
  • 67 107 840 ÷ 2 = 33 553 920 + 0;
  • 33 553 920 ÷ 2 = 16 776 960 + 0;
  • 16 776 960 ÷ 2 = 8 388 480 + 0;
  • 8 388 480 ÷ 2 = 4 194 240 + 0;
  • 4 194 240 ÷ 2 = 2 097 120 + 0;
  • 2 097 120 ÷ 2 = 1 048 560 + 0;
  • 1 048 560 ÷ 2 = 524 280 + 0;
  • 524 280 ÷ 2 = 262 140 + 0;
  • 262 140 ÷ 2 = 131 070 + 0;
  • 131 070 ÷ 2 = 65 535 + 0;
  • 65 535 ÷ 2 = 32 767 + 1;
  • 32 767 ÷ 2 = 16 383 + 1;
  • 16 383 ÷ 2 = 8 191 + 1;
  • 8 191 ÷ 2 = 4 095 + 1;
  • 4 095 ÷ 2 = 2 047 + 1;
  • 2 047 ÷ 2 = 1 023 + 1;
  • 1 023 ÷ 2 = 511 + 1;
  • 511 ÷ 2 = 255 + 1;
  • 255 ÷ 2 = 127 + 1;
  • 127 ÷ 2 = 63 + 1;
  • 63 ÷ 2 = 31 + 1;
  • 31 ÷ 2 = 15 + 1;
  • 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:

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

281 470 681 808 880(10) = 1111 1111 1111 1111 0000 0000 0000 0000 1111 1111 1111 0000(2)


4. Determine the signed binary number bit length:

  • The base 2 number's actual length, in bits: 48.

  • 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) is reserved for 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, 48,

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


=== is: 64.


5. 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:


281 470 681 808 880(10) = 0000 0000 0000 0000 1111 1111 1111 1111 0000 0000 0000 0000 1111 1111 1111 0000

6. Get the negative integer number representation:

To get the negative integer number representation on 64 bits (8 Bytes),


... change the first bit (the leftmost), from 0 to 1...


-281 470 681 808 880(10) Base 10 integer number converted and written as a signed binary code (in base 2):

-281 470 681 808 880(10) = 1000 0000 0000 0000 1111 1111 1111 1111 0000 0000 0000 0000 1111 1111 1111 0000

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


How to convert signed base 10 integers in decimal to binary code system

Follow the steps below to convert a signed base ten integer number to signed binary:

  • 1. In a signed binary, first bit (the leftmost) is reserved for sign: 0 = positive integer number, 1 = positive integer number. If the number to be converted is negative, start with its positive version.
  • 2. Divide repeatedly by 2 the positive integer number keeping track of each remainder. STOP when 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 have a length of 4, 8, 16, 32, 64, ... bits (power of 2) - if needed, fill in extra '0' bits in front of the base 2 number (to the left), up to the right length; this way the first bit (the leftmost one) is always '0', as for a positive representation.
  • 5. To get the negative reprezentation of the number, simply switch the first bit (the leftmost one), from '0' to '1'.

Example: convert the negative number -63 from decimal system (base ten) to signed binary code system:

  • 1. Start with the positive version of the number: |-63| = 63;
  • 2. Divide repeatedly 63 by 2, keeping track of each remainder, until we get a quotient that is equal to zero:
    • division = quotient + remainder
    • 63 ÷ 2 = 31 + 1
    • 31 ÷ 2 = 15 + 1
    • 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:
    63(10) = 11 1111(2)
  • 4. The actual length of base 2 representation number is 6, so the positive binary computer representation length of the signed binary will take in this case 8 bits (the least power of 2 higher than 6) - add extra '0's in front (to the left), up to the required length; this way the first bit (the leftmost one) is to be '0', as for a positive number:
    63(10) = 0011 1111(2)
  • 5. To get the negative integer number representation simply change the first bit (the leftmost), from '0' to '1':
    -63(10) = 1011 1111
  • Number -63(10), signed integer, converted from decimal system (base 10) to signed binary = 1011 1111