24.777 777 777 777 777 780 28 Converted to 64 Bit Double Precision IEEE 754 Binary Floating Point Representation Standard

Convert decimal 24.777 777 777 777 777 780 28(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
24.777 777 777 777 777 780 28(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: 0.777 777 777 777 777 780 28.

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) 0.777 777 777 777 777 780 28 × 2 = 1 + 0.555 555 555 555 555 560 56;
  • 2) 0.555 555 555 555 555 560 56 × 2 = 1 + 0.111 111 111 111 111 121 12;
  • 3) 0.111 111 111 111 111 121 12 × 2 = 0 + 0.222 222 222 222 222 242 24;
  • 4) 0.222 222 222 222 222 242 24 × 2 = 0 + 0.444 444 444 444 444 484 48;
  • 5) 0.444 444 444 444 444 484 48 × 2 = 0 + 0.888 888 888 888 888 968 96;
  • 6) 0.888 888 888 888 888 968 96 × 2 = 1 + 0.777 777 777 777 777 937 92;
  • 7) 0.777 777 777 777 777 937 92 × 2 = 1 + 0.555 555 555 555 555 875 84;
  • 8) 0.555 555 555 555 555 875 84 × 2 = 1 + 0.111 111 111 111 111 751 68;
  • 9) 0.111 111 111 111 111 751 68 × 2 = 0 + 0.222 222 222 222 223 503 36;
  • 10) 0.222 222 222 222 223 503 36 × 2 = 0 + 0.444 444 444 444 447 006 72;
  • 11) 0.444 444 444 444 447 006 72 × 2 = 0 + 0.888 888 888 888 894 013 44;
  • 12) 0.888 888 888 888 894 013 44 × 2 = 1 + 0.777 777 777 777 788 026 88;
  • 13) 0.777 777 777 777 788 026 88 × 2 = 1 + 0.555 555 555 555 576 053 76;
  • 14) 0.555 555 555 555 576 053 76 × 2 = 1 + 0.111 111 111 111 152 107 52;
  • 15) 0.111 111 111 111 152 107 52 × 2 = 0 + 0.222 222 222 222 304 215 04;
  • 16) 0.222 222 222 222 304 215 04 × 2 = 0 + 0.444 444 444 444 608 430 08;
  • 17) 0.444 444 444 444 608 430 08 × 2 = 0 + 0.888 888 888 889 216 860 16;
  • 18) 0.888 888 888 889 216 860 16 × 2 = 1 + 0.777 777 777 778 433 720 32;
  • 19) 0.777 777 777 778 433 720 32 × 2 = 1 + 0.555 555 555 556 867 440 64;
  • 20) 0.555 555 555 556 867 440 64 × 2 = 1 + 0.111 111 111 113 734 881 28;
  • 21) 0.111 111 111 113 734 881 28 × 2 = 0 + 0.222 222 222 227 469 762 56;
  • 22) 0.222 222 222 227 469 762 56 × 2 = 0 + 0.444 444 444 454 939 525 12;
  • 23) 0.444 444 444 454 939 525 12 × 2 = 0 + 0.888 888 888 909 879 050 24;
  • 24) 0.888 888 888 909 879 050 24 × 2 = 1 + 0.777 777 777 819 758 100 48;
  • 25) 0.777 777 777 819 758 100 48 × 2 = 1 + 0.555 555 555 639 516 200 96;
  • 26) 0.555 555 555 639 516 200 96 × 2 = 1 + 0.111 111 111 279 032 401 92;
  • 27) 0.111 111 111 279 032 401 92 × 2 = 0 + 0.222 222 222 558 064 803 84;
  • 28) 0.222 222 222 558 064 803 84 × 2 = 0 + 0.444 444 445 116 129 607 68;
  • 29) 0.444 444 445 116 129 607 68 × 2 = 0 + 0.888 888 890 232 259 215 36;
  • 30) 0.888 888 890 232 259 215 36 × 2 = 1 + 0.777 777 780 464 518 430 72;
  • 31) 0.777 777 780 464 518 430 72 × 2 = 1 + 0.555 555 560 929 036 861 44;
  • 32) 0.555 555 560 929 036 861 44 × 2 = 1 + 0.111 111 121 858 073 722 88;
  • 33) 0.111 111 121 858 073 722 88 × 2 = 0 + 0.222 222 243 716 147 445 76;
  • 34) 0.222 222 243 716 147 445 76 × 2 = 0 + 0.444 444 487 432 294 891 52;
  • 35) 0.444 444 487 432 294 891 52 × 2 = 0 + 0.888 888 974 864 589 783 04;
  • 36) 0.888 888 974 864 589 783 04 × 2 = 1 + 0.777 777 949 729 179 566 08;
  • 37) 0.777 777 949 729 179 566 08 × 2 = 1 + 0.555 555 899 458 359 132 16;
  • 38) 0.555 555 899 458 359 132 16 × 2 = 1 + 0.111 111 798 916 718 264 32;
  • 39) 0.111 111 798 916 718 264 32 × 2 = 0 + 0.222 223 597 833 436 528 64;
  • 40) 0.222 223 597 833 436 528 64 × 2 = 0 + 0.444 447 195 666 873 057 28;
  • 41) 0.444 447 195 666 873 057 28 × 2 = 0 + 0.888 894 391 333 746 114 56;
  • 42) 0.888 894 391 333 746 114 56 × 2 = 1 + 0.777 788 782 667 492 229 12;
  • 43) 0.777 788 782 667 492 229 12 × 2 = 1 + 0.555 577 565 334 984 458 24;
  • 44) 0.555 577 565 334 984 458 24 × 2 = 1 + 0.111 155 130 669 968 916 48;
  • 45) 0.111 155 130 669 968 916 48 × 2 = 0 + 0.222 310 261 339 937 832 96;
  • 46) 0.222 310 261 339 937 832 96 × 2 = 0 + 0.444 620 522 679 875 665 92;
  • 47) 0.444 620 522 679 875 665 92 × 2 = 0 + 0.889 241 045 359 751 331 84;
  • 48) 0.889 241 045 359 751 331 84 × 2 = 1 + 0.778 482 090 719 502 663 68;
  • 49) 0.778 482 090 719 502 663 68 × 2 = 1 + 0.556 964 181 439 005 327 36;
  • 50) 0.556 964 181 439 005 327 36 × 2 = 1 + 0.113 928 362 878 010 654 72;
  • 51) 0.113 928 362 878 010 654 72 × 2 = 0 + 0.227 856 725 756 021 309 44;
  • 52) 0.227 856 725 756 021 309 44 × 2 = 0 + 0.455 713 451 512 042 618 88;
  • 53) 0.455 713 451 512 042 618 88 × 2 = 0 + 0.911 426 903 024 085 237 76;

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:


0.777 777 777 777 777 780 28(10) =


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

5. Positive number before normalization:

24.777 777 777 777 777 780 28(10) =


1 1000.1100 0111 0001 1100 0111 0001 1100 0111 0001 1100 0111 0001 1100 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:


24.777 777 777 777 777 780 28(10) =


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


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


1.1000 1100 0111 0001 1100 0111 0001 1100 0111 0001 1100 0111 0001 1100 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 0001 1100 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 0001 1 1000 =


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


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 0001


Decimal number 24.777 777 777 777 777 780 28 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 0001


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