24.777 777 777 777 777 780 23 Converted to 64 Bit Double Precision IEEE 754 Binary Floating Point Representation Standard

Convert decimal 24.777 777 777 777 777 780 23(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 23(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 23.

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 23 × 2 = 1 + 0.555 555 555 555 555 560 46;
  • 2) 0.555 555 555 555 555 560 46 × 2 = 1 + 0.111 111 111 111 111 120 92;
  • 3) 0.111 111 111 111 111 120 92 × 2 = 0 + 0.222 222 222 222 222 241 84;
  • 4) 0.222 222 222 222 222 241 84 × 2 = 0 + 0.444 444 444 444 444 483 68;
  • 5) 0.444 444 444 444 444 483 68 × 2 = 0 + 0.888 888 888 888 888 967 36;
  • 6) 0.888 888 888 888 888 967 36 × 2 = 1 + 0.777 777 777 777 777 934 72;
  • 7) 0.777 777 777 777 777 934 72 × 2 = 1 + 0.555 555 555 555 555 869 44;
  • 8) 0.555 555 555 555 555 869 44 × 2 = 1 + 0.111 111 111 111 111 738 88;
  • 9) 0.111 111 111 111 111 738 88 × 2 = 0 + 0.222 222 222 222 223 477 76;
  • 10) 0.222 222 222 222 223 477 76 × 2 = 0 + 0.444 444 444 444 446 955 52;
  • 11) 0.444 444 444 444 446 955 52 × 2 = 0 + 0.888 888 888 888 893 911 04;
  • 12) 0.888 888 888 888 893 911 04 × 2 = 1 + 0.777 777 777 777 787 822 08;
  • 13) 0.777 777 777 777 787 822 08 × 2 = 1 + 0.555 555 555 555 575 644 16;
  • 14) 0.555 555 555 555 575 644 16 × 2 = 1 + 0.111 111 111 111 151 288 32;
  • 15) 0.111 111 111 111 151 288 32 × 2 = 0 + 0.222 222 222 222 302 576 64;
  • 16) 0.222 222 222 222 302 576 64 × 2 = 0 + 0.444 444 444 444 605 153 28;
  • 17) 0.444 444 444 444 605 153 28 × 2 = 0 + 0.888 888 888 889 210 306 56;
  • 18) 0.888 888 888 889 210 306 56 × 2 = 1 + 0.777 777 777 778 420 613 12;
  • 19) 0.777 777 777 778 420 613 12 × 2 = 1 + 0.555 555 555 556 841 226 24;
  • 20) 0.555 555 555 556 841 226 24 × 2 = 1 + 0.111 111 111 113 682 452 48;
  • 21) 0.111 111 111 113 682 452 48 × 2 = 0 + 0.222 222 222 227 364 904 96;
  • 22) 0.222 222 222 227 364 904 96 × 2 = 0 + 0.444 444 444 454 729 809 92;
  • 23) 0.444 444 444 454 729 809 92 × 2 = 0 + 0.888 888 888 909 459 619 84;
  • 24) 0.888 888 888 909 459 619 84 × 2 = 1 + 0.777 777 777 818 919 239 68;
  • 25) 0.777 777 777 818 919 239 68 × 2 = 1 + 0.555 555 555 637 838 479 36;
  • 26) 0.555 555 555 637 838 479 36 × 2 = 1 + 0.111 111 111 275 676 958 72;
  • 27) 0.111 111 111 275 676 958 72 × 2 = 0 + 0.222 222 222 551 353 917 44;
  • 28) 0.222 222 222 551 353 917 44 × 2 = 0 + 0.444 444 445 102 707 834 88;
  • 29) 0.444 444 445 102 707 834 88 × 2 = 0 + 0.888 888 890 205 415 669 76;
  • 30) 0.888 888 890 205 415 669 76 × 2 = 1 + 0.777 777 780 410 831 339 52;
  • 31) 0.777 777 780 410 831 339 52 × 2 = 1 + 0.555 555 560 821 662 679 04;
  • 32) 0.555 555 560 821 662 679 04 × 2 = 1 + 0.111 111 121 643 325 358 08;
  • 33) 0.111 111 121 643 325 358 08 × 2 = 0 + 0.222 222 243 286 650 716 16;
  • 34) 0.222 222 243 286 650 716 16 × 2 = 0 + 0.444 444 486 573 301 432 32;
  • 35) 0.444 444 486 573 301 432 32 × 2 = 0 + 0.888 888 973 146 602 864 64;
  • 36) 0.888 888 973 146 602 864 64 × 2 = 1 + 0.777 777 946 293 205 729 28;
  • 37) 0.777 777 946 293 205 729 28 × 2 = 1 + 0.555 555 892 586 411 458 56;
  • 38) 0.555 555 892 586 411 458 56 × 2 = 1 + 0.111 111 785 172 822 917 12;
  • 39) 0.111 111 785 172 822 917 12 × 2 = 0 + 0.222 223 570 345 645 834 24;
  • 40) 0.222 223 570 345 645 834 24 × 2 = 0 + 0.444 447 140 691 291 668 48;
  • 41) 0.444 447 140 691 291 668 48 × 2 = 0 + 0.888 894 281 382 583 336 96;
  • 42) 0.888 894 281 382 583 336 96 × 2 = 1 + 0.777 788 562 765 166 673 92;
  • 43) 0.777 788 562 765 166 673 92 × 2 = 1 + 0.555 577 125 530 333 347 84;
  • 44) 0.555 577 125 530 333 347 84 × 2 = 1 + 0.111 154 251 060 666 695 68;
  • 45) 0.111 154 251 060 666 695 68 × 2 = 0 + 0.222 308 502 121 333 391 36;
  • 46) 0.222 308 502 121 333 391 36 × 2 = 0 + 0.444 617 004 242 666 782 72;
  • 47) 0.444 617 004 242 666 782 72 × 2 = 0 + 0.889 234 008 485 333 565 44;
  • 48) 0.889 234 008 485 333 565 44 × 2 = 1 + 0.778 468 016 970 667 130 88;
  • 49) 0.778 468 016 970 667 130 88 × 2 = 1 + 0.556 936 033 941 334 261 76;
  • 50) 0.556 936 033 941 334 261 76 × 2 = 1 + 0.113 872 067 882 668 523 52;
  • 51) 0.113 872 067 882 668 523 52 × 2 = 0 + 0.227 744 135 765 337 047 04;
  • 52) 0.227 744 135 765 337 047 04 × 2 = 0 + 0.455 488 271 530 674 094 08;
  • 53) 0.455 488 271 530 674 094 08 × 2 = 0 + 0.910 976 543 061 348 188 16;

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 23(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 23(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 23(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 23 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