24.777 777 777 777 777 775 82 Converted to 64 Bit Double Precision IEEE 754 Binary Floating Point Representation Standard

Convert decimal 24.777 777 777 777 777 775 82(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
24.777 777 777 777 777 775 82(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: 0.777 777 777 777 777 775 82.

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) 0.777 777 777 777 777 775 82 × 2 = 1 + 0.555 555 555 555 555 551 64;
  • 2) 0.555 555 555 555 555 551 64 × 2 = 1 + 0.111 111 111 111 111 103 28;
  • 3) 0.111 111 111 111 111 103 28 × 2 = 0 + 0.222 222 222 222 222 206 56;
  • 4) 0.222 222 222 222 222 206 56 × 2 = 0 + 0.444 444 444 444 444 413 12;
  • 5) 0.444 444 444 444 444 413 12 × 2 = 0 + 0.888 888 888 888 888 826 24;
  • 6) 0.888 888 888 888 888 826 24 × 2 = 1 + 0.777 777 777 777 777 652 48;
  • 7) 0.777 777 777 777 777 652 48 × 2 = 1 + 0.555 555 555 555 555 304 96;
  • 8) 0.555 555 555 555 555 304 96 × 2 = 1 + 0.111 111 111 111 110 609 92;
  • 9) 0.111 111 111 111 110 609 92 × 2 = 0 + 0.222 222 222 222 221 219 84;
  • 10) 0.222 222 222 222 221 219 84 × 2 = 0 + 0.444 444 444 444 442 439 68;
  • 11) 0.444 444 444 444 442 439 68 × 2 = 0 + 0.888 888 888 888 884 879 36;
  • 12) 0.888 888 888 888 884 879 36 × 2 = 1 + 0.777 777 777 777 769 758 72;
  • 13) 0.777 777 777 777 769 758 72 × 2 = 1 + 0.555 555 555 555 539 517 44;
  • 14) 0.555 555 555 555 539 517 44 × 2 = 1 + 0.111 111 111 111 079 034 88;
  • 15) 0.111 111 111 111 079 034 88 × 2 = 0 + 0.222 222 222 222 158 069 76;
  • 16) 0.222 222 222 222 158 069 76 × 2 = 0 + 0.444 444 444 444 316 139 52;
  • 17) 0.444 444 444 444 316 139 52 × 2 = 0 + 0.888 888 888 888 632 279 04;
  • 18) 0.888 888 888 888 632 279 04 × 2 = 1 + 0.777 777 777 777 264 558 08;
  • 19) 0.777 777 777 777 264 558 08 × 2 = 1 + 0.555 555 555 554 529 116 16;
  • 20) 0.555 555 555 554 529 116 16 × 2 = 1 + 0.111 111 111 109 058 232 32;
  • 21) 0.111 111 111 109 058 232 32 × 2 = 0 + 0.222 222 222 218 116 464 64;
  • 22) 0.222 222 222 218 116 464 64 × 2 = 0 + 0.444 444 444 436 232 929 28;
  • 23) 0.444 444 444 436 232 929 28 × 2 = 0 + 0.888 888 888 872 465 858 56;
  • 24) 0.888 888 888 872 465 858 56 × 2 = 1 + 0.777 777 777 744 931 717 12;
  • 25) 0.777 777 777 744 931 717 12 × 2 = 1 + 0.555 555 555 489 863 434 24;
  • 26) 0.555 555 555 489 863 434 24 × 2 = 1 + 0.111 111 110 979 726 868 48;
  • 27) 0.111 111 110 979 726 868 48 × 2 = 0 + 0.222 222 221 959 453 736 96;
  • 28) 0.222 222 221 959 453 736 96 × 2 = 0 + 0.444 444 443 918 907 473 92;
  • 29) 0.444 444 443 918 907 473 92 × 2 = 0 + 0.888 888 887 837 814 947 84;
  • 30) 0.888 888 887 837 814 947 84 × 2 = 1 + 0.777 777 775 675 629 895 68;
  • 31) 0.777 777 775 675 629 895 68 × 2 = 1 + 0.555 555 551 351 259 791 36;
  • 32) 0.555 555 551 351 259 791 36 × 2 = 1 + 0.111 111 102 702 519 582 72;
  • 33) 0.111 111 102 702 519 582 72 × 2 = 0 + 0.222 222 205 405 039 165 44;
  • 34) 0.222 222 205 405 039 165 44 × 2 = 0 + 0.444 444 410 810 078 330 88;
  • 35) 0.444 444 410 810 078 330 88 × 2 = 0 + 0.888 888 821 620 156 661 76;
  • 36) 0.888 888 821 620 156 661 76 × 2 = 1 + 0.777 777 643 240 313 323 52;
  • 37) 0.777 777 643 240 313 323 52 × 2 = 1 + 0.555 555 286 480 626 647 04;
  • 38) 0.555 555 286 480 626 647 04 × 2 = 1 + 0.111 110 572 961 253 294 08;
  • 39) 0.111 110 572 961 253 294 08 × 2 = 0 + 0.222 221 145 922 506 588 16;
  • 40) 0.222 221 145 922 506 588 16 × 2 = 0 + 0.444 442 291 845 013 176 32;
  • 41) 0.444 442 291 845 013 176 32 × 2 = 0 + 0.888 884 583 690 026 352 64;
  • 42) 0.888 884 583 690 026 352 64 × 2 = 1 + 0.777 769 167 380 052 705 28;
  • 43) 0.777 769 167 380 052 705 28 × 2 = 1 + 0.555 538 334 760 105 410 56;
  • 44) 0.555 538 334 760 105 410 56 × 2 = 1 + 0.111 076 669 520 210 821 12;
  • 45) 0.111 076 669 520 210 821 12 × 2 = 0 + 0.222 153 339 040 421 642 24;
  • 46) 0.222 153 339 040 421 642 24 × 2 = 0 + 0.444 306 678 080 843 284 48;
  • 47) 0.444 306 678 080 843 284 48 × 2 = 0 + 0.888 613 356 161 686 568 96;
  • 48) 0.888 613 356 161 686 568 96 × 2 = 1 + 0.777 226 712 323 373 137 92;
  • 49) 0.777 226 712 323 373 137 92 × 2 = 1 + 0.554 453 424 646 746 275 84;
  • 50) 0.554 453 424 646 746 275 84 × 2 = 1 + 0.108 906 849 293 492 551 68;
  • 51) 0.108 906 849 293 492 551 68 × 2 = 0 + 0.217 813 698 586 985 103 36;
  • 52) 0.217 813 698 586 985 103 36 × 2 = 0 + 0.435 627 397 173 970 206 72;
  • 53) 0.435 627 397 173 970 206 72 × 2 = 0 + 0.871 254 794 347 940 413 44;

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:


0.777 777 777 777 777 775 82(10) =


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

5. Positive number before normalization:

24.777 777 777 777 777 775 82(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:


24.777 777 777 777 777 775 82(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 24.777 777 777 777 777 775 82 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