24.777 777 777 777 779 99 Converted to 64 Bit Double Precision IEEE 754 Binary Floating Point Representation Standard

Convert decimal 24.777 777 777 777 779 99(10) to 64 bit double precision IEEE 754 binary floating point representation standard (1 bit for sign, 11 bits for exponent, 52 bits for mantissa)

What are the steps to convert decimal number
24.777 777 777 777 779 99(10) to 64 bit double precision IEEE 754 binary floating point representation (1 bit for sign, 11 bits for exponent, 52 bits for mantissa)

1. First, convert to binary (in base 2) the integer part: 24.
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;
  • 24 ÷ 2 = 12 + 0;
  • 12 ÷ 2 = 6 + 0;
  • 6 ÷ 2 = 3 + 0;
  • 3 ÷ 2 = 1 + 1;
  • 1 ÷ 2 = 0 + 1;

2. Construct the base 2 representation of the integer part of the number.

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

24(10) =


1 1000(2)


3. Convert to binary (base 2) the fractional part: 0.777 777 777 777 779 99.

Multiply it repeatedly by 2.


Keep track of each integer part of the results.


Stop when we get a fractional part that is equal to zero.


  • #) multiplying = integer + fractional part;
  • 1) 0.777 777 777 777 779 99 × 2 = 1 + 0.555 555 555 555 559 98;
  • 2) 0.555 555 555 555 559 98 × 2 = 1 + 0.111 111 111 111 119 96;
  • 3) 0.111 111 111 111 119 96 × 2 = 0 + 0.222 222 222 222 239 92;
  • 4) 0.222 222 222 222 239 92 × 2 = 0 + 0.444 444 444 444 479 84;
  • 5) 0.444 444 444 444 479 84 × 2 = 0 + 0.888 888 888 888 959 68;
  • 6) 0.888 888 888 888 959 68 × 2 = 1 + 0.777 777 777 777 919 36;
  • 7) 0.777 777 777 777 919 36 × 2 = 1 + 0.555 555 555 555 838 72;
  • 8) 0.555 555 555 555 838 72 × 2 = 1 + 0.111 111 111 111 677 44;
  • 9) 0.111 111 111 111 677 44 × 2 = 0 + 0.222 222 222 223 354 88;
  • 10) 0.222 222 222 223 354 88 × 2 = 0 + 0.444 444 444 446 709 76;
  • 11) 0.444 444 444 446 709 76 × 2 = 0 + 0.888 888 888 893 419 52;
  • 12) 0.888 888 888 893 419 52 × 2 = 1 + 0.777 777 777 786 839 04;
  • 13) 0.777 777 777 786 839 04 × 2 = 1 + 0.555 555 555 573 678 08;
  • 14) 0.555 555 555 573 678 08 × 2 = 1 + 0.111 111 111 147 356 16;
  • 15) 0.111 111 111 147 356 16 × 2 = 0 + 0.222 222 222 294 712 32;
  • 16) 0.222 222 222 294 712 32 × 2 = 0 + 0.444 444 444 589 424 64;
  • 17) 0.444 444 444 589 424 64 × 2 = 0 + 0.888 888 889 178 849 28;
  • 18) 0.888 888 889 178 849 28 × 2 = 1 + 0.777 777 778 357 698 56;
  • 19) 0.777 777 778 357 698 56 × 2 = 1 + 0.555 555 556 715 397 12;
  • 20) 0.555 555 556 715 397 12 × 2 = 1 + 0.111 111 113 430 794 24;
  • 21) 0.111 111 113 430 794 24 × 2 = 0 + 0.222 222 226 861 588 48;
  • 22) 0.222 222 226 861 588 48 × 2 = 0 + 0.444 444 453 723 176 96;
  • 23) 0.444 444 453 723 176 96 × 2 = 0 + 0.888 888 907 446 353 92;
  • 24) 0.888 888 907 446 353 92 × 2 = 1 + 0.777 777 814 892 707 84;
  • 25) 0.777 777 814 892 707 84 × 2 = 1 + 0.555 555 629 785 415 68;
  • 26) 0.555 555 629 785 415 68 × 2 = 1 + 0.111 111 259 570 831 36;
  • 27) 0.111 111 259 570 831 36 × 2 = 0 + 0.222 222 519 141 662 72;
  • 28) 0.222 222 519 141 662 72 × 2 = 0 + 0.444 445 038 283 325 44;
  • 29) 0.444 445 038 283 325 44 × 2 = 0 + 0.888 890 076 566 650 88;
  • 30) 0.888 890 076 566 650 88 × 2 = 1 + 0.777 780 153 133 301 76;
  • 31) 0.777 780 153 133 301 76 × 2 = 1 + 0.555 560 306 266 603 52;
  • 32) 0.555 560 306 266 603 52 × 2 = 1 + 0.111 120 612 533 207 04;
  • 33) 0.111 120 612 533 207 04 × 2 = 0 + 0.222 241 225 066 414 08;
  • 34) 0.222 241 225 066 414 08 × 2 = 0 + 0.444 482 450 132 828 16;
  • 35) 0.444 482 450 132 828 16 × 2 = 0 + 0.888 964 900 265 656 32;
  • 36) 0.888 964 900 265 656 32 × 2 = 1 + 0.777 929 800 531 312 64;
  • 37) 0.777 929 800 531 312 64 × 2 = 1 + 0.555 859 601 062 625 28;
  • 38) 0.555 859 601 062 625 28 × 2 = 1 + 0.111 719 202 125 250 56;
  • 39) 0.111 719 202 125 250 56 × 2 = 0 + 0.223 438 404 250 501 12;
  • 40) 0.223 438 404 250 501 12 × 2 = 0 + 0.446 876 808 501 002 24;
  • 41) 0.446 876 808 501 002 24 × 2 = 0 + 0.893 753 617 002 004 48;
  • 42) 0.893 753 617 002 004 48 × 2 = 1 + 0.787 507 234 004 008 96;
  • 43) 0.787 507 234 004 008 96 × 2 = 1 + 0.575 014 468 008 017 92;
  • 44) 0.575 014 468 008 017 92 × 2 = 1 + 0.150 028 936 016 035 84;
  • 45) 0.150 028 936 016 035 84 × 2 = 0 + 0.300 057 872 032 071 68;
  • 46) 0.300 057 872 032 071 68 × 2 = 0 + 0.600 115 744 064 143 36;
  • 47) 0.600 115 744 064 143 36 × 2 = 1 + 0.200 231 488 128 286 72;
  • 48) 0.200 231 488 128 286 72 × 2 = 0 + 0.400 462 976 256 573 44;
  • 49) 0.400 462 976 256 573 44 × 2 = 0 + 0.800 925 952 513 146 88;
  • 50) 0.800 925 952 513 146 88 × 2 = 1 + 0.601 851 905 026 293 76;
  • 51) 0.601 851 905 026 293 76 × 2 = 1 + 0.203 703 810 052 587 52;
  • 52) 0.203 703 810 052 587 52 × 2 = 0 + 0.407 407 620 105 175 04;
  • 53) 0.407 407 620 105 175 04 × 2 = 0 + 0.814 815 240 210 350 08;

We didn't get any fractional part that was equal to zero. But we had enough iterations (over Mantissa limit) and at least one integer that was different from zero => FULL STOP (Losing precision - the converted number we get in the end will be just a very good approximation of the initial one).


4. Construct the base 2 representation of the fractional part of the number.

Take all the integer parts of the multiplying operations, starting from the top of the constructed list above:


0.777 777 777 777 779 99(10) =


0.1100 0111 0001 1100 0111 0001 1100 0111 0001 1100 0111 0010 0110 0(2)

5. Positive number before normalization:

24.777 777 777 777 779 99(10) =


1 1000.1100 0111 0001 1100 0111 0001 1100 0111 0001 1100 0111 0010 0110 0(2)

6. Normalize the binary representation of the number.

Shift the decimal mark 4 positions to the left, so that only one non zero digit remains to the left of it:


24.777 777 777 777 779 99(10) =


1 1000.1100 0111 0001 1100 0111 0001 1100 0111 0001 1100 0111 0010 0110 0(2) =


1 1000.1100 0111 0001 1100 0111 0001 1100 0111 0001 1100 0111 0010 0110 0(2) × 20 =


1.1000 1100 0111 0001 1100 0111 0001 1100 0111 0001 1100 0111 0010 0110 0(2) × 24


7. Up to this moment, there are the following elements that would feed into the 64 bit double precision IEEE 754 binary floating point representation:

Sign 0 (a positive number)


Exponent (unadjusted): 4


Mantissa (not normalized):
1.1000 1100 0111 0001 1100 0111 0001 1100 0111 0001 1100 0111 0010 0110 0


8. Adjust the exponent.

Use the 11 bit excess/bias notation:


Exponent (adjusted) =


Exponent (unadjusted) + 2(11-1) - 1 =


4 + 2(11-1) - 1 =


(4 + 1 023)(10) =


1 027(10)


9. Convert the adjusted exponent from the decimal (base 10) to 11 bit binary.

Use the same technique of repeatedly dividing by 2:


  • division = quotient + remainder;
  • 1 027 ÷ 2 = 513 + 1;
  • 513 ÷ 2 = 256 + 1;
  • 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;

10. Construct the base 2 representation of the adjusted exponent.

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


Exponent (adjusted) =


1027(10) =


100 0000 0011(2)


11. Normalize the mantissa.

a) Remove the leading (the leftmost) bit, since it's allways 1, and the decimal point, if the case.


b) Adjust its length to 52 bits, by removing the excess bits, from the right (if any of the excess bits is set on 1, we are losing precision...).


Mantissa (normalized) =


1. 1000 1100 0111 0001 1100 0111 0001 1100 0111 0001 1100 0111 0010 0 1100 =


1000 1100 0111 0001 1100 0111 0001 1100 0111 0001 1100 0111 0010


12. The three elements that make up the number's 64 bit double precision IEEE 754 binary floating point representation:

Sign (1 bit) =
0 (a positive number)


Exponent (11 bits) =
100 0000 0011


Mantissa (52 bits) =
1000 1100 0111 0001 1100 0111 0001 1100 0111 0001 1100 0111 0010


Decimal number 24.777 777 777 777 779 99 converted to 64 bit double precision IEEE 754 binary floating point representation:

0 - 100 0000 0011 - 1000 1100 0111 0001 1100 0111 0001 1100 0111 0001 1100 0111 0010


How to convert numbers from the decimal system (base ten) to 64 bit double precision IEEE 754 binary floating point standard

Follow the steps below to convert a base 10 decimal number to 64 bit double precision IEEE 754 binary floating point:

  • 1. If the number to be converted is negative, start with its the positive version.
  • 2. First convert the integer part. Divide repeatedly by 2 the positive representation of the integer number that is to be converted to binary, until we get a quotient that is equal to zero, keeping track of each remainder.
  • 3. Construct the base 2 representation of the positive integer part of the number, by taking all the remainders from the previous operations, 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. Then convert the fractional part. Multiply the number repeatedly by 2, until we get a fractional part that is equal to zero, keeping track of each integer part of the results.
  • 5. Construct the base 2 representation of the fractional part of the number, by taking all the integer parts of the multiplying operations, starting from the top of the list constructed above (they should appear in the binary representation, from left to right, in the order they have been calculated).
  • 6. Normalize the binary representation of the number, shifting the decimal mark (the decimal point) "n" positions either to the left, or to the right, so that only one non zero digit remains to the left of the decimal mark.
  • 7. Adjust the exponent in 11 bit excess/bias notation and then convert it from decimal (base 10) to 11 bit binary, by using the same technique of repeatedly dividing by 2, as shown above:
    Exponent (adjusted) = Exponent (unadjusted) + 2(11-1) - 1
  • 8. Normalize mantissa, remove the leading (leftmost) bit, since it's allways '1' (and the decimal mark, if the case) and adjust its length to 52 bits, either by removing the excess bits from the right (losing precision...) or by adding extra bits set on '0' to the right.
  • 9. Sign (it takes 1 bit) is either 1 for a negative or 0 for a positive number.

Example: convert the negative number -31.640 215 from the decimal system (base ten) to 64 bit double precision IEEE 754 binary floating point:

  • 1. Start with the positive version of the number:

    |-31.640 215| = 31.640 215

  • 2. First convert the integer part, 31. Divide it repeatedly by 2, keeping track of each remainder, until we get a quotient that is equal to zero:
    • division = quotient + remainder;
    • 31 ÷ 2 = 15 + 1;
    • 15 ÷ 2 = 7 + 1;
    • 7 ÷ 2 = 3 + 1;
    • 3 ÷ 2 = 1 + 1;
    • 1 ÷ 2 = 0 + 1;
    • We have encountered a quotient that is ZERO => FULL STOP
  • 3. Construct the base 2 representation of the integer part of the number by taking all the remainders of the previous dividing operations, starting from the bottom of the list constructed above:

    31(10) = 1 1111(2)

  • 4. Then, convert the fractional part, 0.640 215. Multiply repeatedly by 2, keeping track of each integer part of the results, until we get a fractional part that is equal to zero:
    • #) multiplying = integer + fractional part;
    • 1) 0.640 215 × 2 = 1 + 0.280 43;
    • 2) 0.280 43 × 2 = 0 + 0.560 86;
    • 3) 0.560 86 × 2 = 1 + 0.121 72;
    • 4) 0.121 72 × 2 = 0 + 0.243 44;
    • 5) 0.243 44 × 2 = 0 + 0.486 88;
    • 6) 0.486 88 × 2 = 0 + 0.973 76;
    • 7) 0.973 76 × 2 = 1 + 0.947 52;
    • 8) 0.947 52 × 2 = 1 + 0.895 04;
    • 9) 0.895 04 × 2 = 1 + 0.790 08;
    • 10) 0.790 08 × 2 = 1 + 0.580 16;
    • 11) 0.580 16 × 2 = 1 + 0.160 32;
    • 12) 0.160 32 × 2 = 0 + 0.320 64;
    • 13) 0.320 64 × 2 = 0 + 0.641 28;
    • 14) 0.641 28 × 2 = 1 + 0.282 56;
    • 15) 0.282 56 × 2 = 0 + 0.565 12;
    • 16) 0.565 12 × 2 = 1 + 0.130 24;
    • 17) 0.130 24 × 2 = 0 + 0.260 48;
    • 18) 0.260 48 × 2 = 0 + 0.520 96;
    • 19) 0.520 96 × 2 = 1 + 0.041 92;
    • 20) 0.041 92 × 2 = 0 + 0.083 84;
    • 21) 0.083 84 × 2 = 0 + 0.167 68;
    • 22) 0.167 68 × 2 = 0 + 0.335 36;
    • 23) 0.335 36 × 2 = 0 + 0.670 72;
    • 24) 0.670 72 × 2 = 1 + 0.341 44;
    • 25) 0.341 44 × 2 = 0 + 0.682 88;
    • 26) 0.682 88 × 2 = 1 + 0.365 76;
    • 27) 0.365 76 × 2 = 0 + 0.731 52;
    • 28) 0.731 52 × 2 = 1 + 0.463 04;
    • 29) 0.463 04 × 2 = 0 + 0.926 08;
    • 30) 0.926 08 × 2 = 1 + 0.852 16;
    • 31) 0.852 16 × 2 = 1 + 0.704 32;
    • 32) 0.704 32 × 2 = 1 + 0.408 64;
    • 33) 0.408 64 × 2 = 0 + 0.817 28;
    • 34) 0.817 28 × 2 = 1 + 0.634 56;
    • 35) 0.634 56 × 2 = 1 + 0.269 12;
    • 36) 0.269 12 × 2 = 0 + 0.538 24;
    • 37) 0.538 24 × 2 = 1 + 0.076 48;
    • 38) 0.076 48 × 2 = 0 + 0.152 96;
    • 39) 0.152 96 × 2 = 0 + 0.305 92;
    • 40) 0.305 92 × 2 = 0 + 0.611 84;
    • 41) 0.611 84 × 2 = 1 + 0.223 68;
    • 42) 0.223 68 × 2 = 0 + 0.447 36;
    • 43) 0.447 36 × 2 = 0 + 0.894 72;
    • 44) 0.894 72 × 2 = 1 + 0.789 44;
    • 45) 0.789 44 × 2 = 1 + 0.578 88;
    • 46) 0.578 88 × 2 = 1 + 0.157 76;
    • 47) 0.157 76 × 2 = 0 + 0.315 52;
    • 48) 0.315 52 × 2 = 0 + 0.631 04;
    • 49) 0.631 04 × 2 = 1 + 0.262 08;
    • 50) 0.262 08 × 2 = 0 + 0.524 16;
    • 51) 0.524 16 × 2 = 1 + 0.048 32;
    • 52) 0.048 32 × 2 = 0 + 0.096 64;
    • 53) 0.096 64 × 2 = 0 + 0.193 28;
    • We didn't get any fractional part that was equal to zero. But we had enough iterations (over Mantissa limit = 52) and at least one integer part that was different from zero => FULL STOP (losing precision...).
  • 5. Construct the base 2 representation of the fractional part of the number, by taking all the integer parts of the previous multiplying operations, starting from the top of the constructed list above:

    0.640 215(10) = 0.1010 0011 1110 0101 0010 0001 0101 0111 0110 1000 1001 1100 1010 0(2)

  • 6. Summarizing - the positive number before normalization:

    31.640 215(10) = 1 1111.1010 0011 1110 0101 0010 0001 0101 0111 0110 1000 1001 1100 1010 0(2)

  • 7. Normalize the binary representation of the number, shifting the decimal mark 4 positions to the left so that only one non-zero digit stays to the left of the decimal mark:

    31.640 215(10) =
    1 1111.1010 0011 1110 0101 0010 0001 0101 0111 0110 1000 1001 1100 1010 0(2) =
    1 1111.1010 0011 1110 0101 0010 0001 0101 0111 0110 1000 1001 1100 1010 0(2) × 20 =
    1.1111 1010 0011 1110 0101 0010 0001 0101 0111 0110 1000 1001 1100 1010 0(2) × 24

  • 8. Up to this moment, there are the following elements that would feed into the 64 bit double precision IEEE 754 binary floating point representation:

    Sign: 1 (a negative number)

    Exponent (unadjusted): 4

    Mantissa (not-normalized): 1.1111 1010 0011 1110 0101 0010 0001 0101 0111 0110 1000 1001 1100 1010 0

  • 9. Adjust the exponent in 11 bit excess/bias notation and then convert it from decimal (base 10) to 11 bit binary (base 2), by using the same technique of repeatedly dividing it by 2, as shown above:

    Exponent (adjusted) = Exponent (unadjusted) + 2(11-1) - 1 = (4 + 1023)(10) = 1027(10) =
    100 0000 0011(2)

  • 10. Normalize mantissa, remove the leading (leftmost) bit, since it's allways '1' (and the decimal sign) and adjust its length to 52 bits, by removing the excess bits, from the right (losing precision...):

    Mantissa (not-normalized): 1.1111 1010 0011 1110 0101 0010 0001 0101 0111 0110 1000 1001 1100 1010 0

    Mantissa (normalized): 1111 1010 0011 1110 0101 0010 0001 0101 0111 0110 1000 1001 1100

  • Conclusion:

    Sign (1 bit) = 1 (a negative number)

    Exponent (8 bits) = 100 0000 0011

    Mantissa (52 bits) = 1111 1010 0011 1110 0101 0010 0001 0101 0111 0110 1000 1001 1100

  • Number -31.640 215, converted from decimal system (base 10) to 64 bit double precision IEEE 754 binary floating point =
    1 - 100 0000 0011 - 1111 1010 0011 1110 0101 0010 0001 0101 0111 0110 1000 1001 1100