Convert -4 611 686 018 427 387 925 to a Signed Binary in Two's (2's) Complement Representation

How to convert decimal number -4 611 686 018 427 387 925(10) to a signed binary in two's (2's) complement representation

What are the steps to convert decimal number
-4 611 686 018 427 387 925 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. Start with the positive version of the number:

|-4 611 686 018 427 387 925| = 4 611 686 018 427 387 925

2. 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;
  • 4 611 686 018 427 387 925 ÷ 2 = 2 305 843 009 213 693 962 + 1;
  • 2 305 843 009 213 693 962 ÷ 2 = 1 152 921 504 606 846 981 + 0;
  • 1 152 921 504 606 846 981 ÷ 2 = 576 460 752 303 423 490 + 1;
  • 576 460 752 303 423 490 ÷ 2 = 288 230 376 151 711 745 + 0;
  • 288 230 376 151 711 745 ÷ 2 = 144 115 188 075 855 872 + 1;
  • 144 115 188 075 855 872 ÷ 2 = 72 057 594 037 927 936 + 0;
  • 72 057 594 037 927 936 ÷ 2 = 36 028 797 018 963 968 + 0;
  • 36 028 797 018 963 968 ÷ 2 = 18 014 398 509 481 984 + 0;
  • 18 014 398 509 481 984 ÷ 2 = 9 007 199 254 740 992 + 0;
  • 9 007 199 254 740 992 ÷ 2 = 4 503 599 627 370 496 + 0;
  • 4 503 599 627 370 496 ÷ 2 = 2 251 799 813 685 248 + 0;
  • 2 251 799 813 685 248 ÷ 2 = 1 125 899 906 842 624 + 0;
  • 1 125 899 906 842 624 ÷ 2 = 562 949 953 421 312 + 0;
  • 562 949 953 421 312 ÷ 2 = 281 474 976 710 656 + 0;
  • 281 474 976 710 656 ÷ 2 = 140 737 488 355 328 + 0;
  • 140 737 488 355 328 ÷ 2 = 70 368 744 177 664 + 0;
  • 70 368 744 177 664 ÷ 2 = 35 184 372 088 832 + 0;
  • 35 184 372 088 832 ÷ 2 = 17 592 186 044 416 + 0;
  • 17 592 186 044 416 ÷ 2 = 8 796 093 022 208 + 0;
  • 8 796 093 022 208 ÷ 2 = 4 398 046 511 104 + 0;
  • 4 398 046 511 104 ÷ 2 = 2 199 023 255 552 + 0;
  • 2 199 023 255 552 ÷ 2 = 1 099 511 627 776 + 0;
  • 1 099 511 627 776 ÷ 2 = 549 755 813 888 + 0;
  • 549 755 813 888 ÷ 2 = 274 877 906 944 + 0;
  • 274 877 906 944 ÷ 2 = 137 438 953 472 + 0;
  • 137 438 953 472 ÷ 2 = 68 719 476 736 + 0;
  • 68 719 476 736 ÷ 2 = 34 359 738 368 + 0;
  • 34 359 738 368 ÷ 2 = 17 179 869 184 + 0;
  • 17 179 869 184 ÷ 2 = 8 589 934 592 + 0;
  • 8 589 934 592 ÷ 2 = 4 294 967 296 + 0;
  • 4 294 967 296 ÷ 2 = 2 147 483 648 + 0;
  • 2 147 483 648 ÷ 2 = 1 073 741 824 + 0;
  • 1 073 741 824 ÷ 2 = 536 870 912 + 0;
  • 536 870 912 ÷ 2 = 268 435 456 + 0;
  • 268 435 456 ÷ 2 = 134 217 728 + 0;
  • 134 217 728 ÷ 2 = 67 108 864 + 0;
  • 67 108 864 ÷ 2 = 33 554 432 + 0;
  • 33 554 432 ÷ 2 = 16 777 216 + 0;
  • 16 777 216 ÷ 2 = 8 388 608 + 0;
  • 8 388 608 ÷ 2 = 4 194 304 + 0;
  • 4 194 304 ÷ 2 = 2 097 152 + 0;
  • 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;

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

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

4 611 686 018 427 387 925(10) = 100 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0001 0101(2)

4. Determine the signed binary number bit length:

  • The base 2 number's actual length, in bits: 63.

  • 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, 63,

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.


4 611 686 018 427 387 925(10) = 0100 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0001 0101

6. Get the negative integer number representation. Part 1:

  • To write the negative integer number on 64 bits (8 Bytes), as a signed binary in one's complement representation, replace all the bits on 0 with 1s and all the bits set on 1 with 0s.

Reverse the digits, flip the digits:

Replace the bits set on 0 with 1s and the bits set on 1 with 0s.

!(0100 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0001 0101)


= 1011 1111 1111 1111 1111 1111 1111 1111 1111 1111 1111 1111 1111 1111 1110 1010


7. Get the negative integer number representation. Part 2:

  • To write the negative integer number on 64 bits (8 Bytes), as a signed binary in two's complement representation, add 1 to the number calculated above 1011 1111 1111 1111 1111 1111 1111 1111 1111 1111 1111 1111 1111 1111 1110 1010 (to the signed binary in one's complement representation).

Binary addition carries on a value of 2:

  • 0 + 0 = 0
  • 0 + 1 = 1
  • 1 + 1 = 10
  • 1 + 10 = 11
  • 1 + 11 = 100

Add 1 to the number calculated above
(to the signed binary number in one's complement representation):

-4 611 686 018 427 387 925 =

1011 1111 1111 1111 1111 1111 1111 1111 1111 1111 1111 1111 1111 1111 1110 1010 + 1


Decimal Number -4 611 686 018 427 387 925(10) converted to signed binary in two's complement representation:

-4 611 686 018 427 387 925(10) = 1011 1111 1111 1111 1111 1111 1111 1111 1111 1111 1111 1111 1111 1111 1110 1011

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