24.777 777 777 777 777 777 3 Converted to 64 Bit Double Precision IEEE 754 Binary Floating Point Representation Standard

Convert decimal 24.777 777 777 777 777 777 3(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
24.777 777 777 777 777 777 3(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: 0.777 777 777 777 777 777 3.

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) 0.777 777 777 777 777 777 3 × 2 = 1 + 0.555 555 555 555 555 554 6;
  • 2) 0.555 555 555 555 555 554 6 × 2 = 1 + 0.111 111 111 111 111 109 2;
  • 3) 0.111 111 111 111 111 109 2 × 2 = 0 + 0.222 222 222 222 222 218 4;
  • 4) 0.222 222 222 222 222 218 4 × 2 = 0 + 0.444 444 444 444 444 436 8;
  • 5) 0.444 444 444 444 444 436 8 × 2 = 0 + 0.888 888 888 888 888 873 6;
  • 6) 0.888 888 888 888 888 873 6 × 2 = 1 + 0.777 777 777 777 777 747 2;
  • 7) 0.777 777 777 777 777 747 2 × 2 = 1 + 0.555 555 555 555 555 494 4;
  • 8) 0.555 555 555 555 555 494 4 × 2 = 1 + 0.111 111 111 111 110 988 8;
  • 9) 0.111 111 111 111 110 988 8 × 2 = 0 + 0.222 222 222 222 221 977 6;
  • 10) 0.222 222 222 222 221 977 6 × 2 = 0 + 0.444 444 444 444 443 955 2;
  • 11) 0.444 444 444 444 443 955 2 × 2 = 0 + 0.888 888 888 888 887 910 4;
  • 12) 0.888 888 888 888 887 910 4 × 2 = 1 + 0.777 777 777 777 775 820 8;
  • 13) 0.777 777 777 777 775 820 8 × 2 = 1 + 0.555 555 555 555 551 641 6;
  • 14) 0.555 555 555 555 551 641 6 × 2 = 1 + 0.111 111 111 111 103 283 2;
  • 15) 0.111 111 111 111 103 283 2 × 2 = 0 + 0.222 222 222 222 206 566 4;
  • 16) 0.222 222 222 222 206 566 4 × 2 = 0 + 0.444 444 444 444 413 132 8;
  • 17) 0.444 444 444 444 413 132 8 × 2 = 0 + 0.888 888 888 888 826 265 6;
  • 18) 0.888 888 888 888 826 265 6 × 2 = 1 + 0.777 777 777 777 652 531 2;
  • 19) 0.777 777 777 777 652 531 2 × 2 = 1 + 0.555 555 555 555 305 062 4;
  • 20) 0.555 555 555 555 305 062 4 × 2 = 1 + 0.111 111 111 110 610 124 8;
  • 21) 0.111 111 111 110 610 124 8 × 2 = 0 + 0.222 222 222 221 220 249 6;
  • 22) 0.222 222 222 221 220 249 6 × 2 = 0 + 0.444 444 444 442 440 499 2;
  • 23) 0.444 444 444 442 440 499 2 × 2 = 0 + 0.888 888 888 884 880 998 4;
  • 24) 0.888 888 888 884 880 998 4 × 2 = 1 + 0.777 777 777 769 761 996 8;
  • 25) 0.777 777 777 769 761 996 8 × 2 = 1 + 0.555 555 555 539 523 993 6;
  • 26) 0.555 555 555 539 523 993 6 × 2 = 1 + 0.111 111 111 079 047 987 2;
  • 27) 0.111 111 111 079 047 987 2 × 2 = 0 + 0.222 222 222 158 095 974 4;
  • 28) 0.222 222 222 158 095 974 4 × 2 = 0 + 0.444 444 444 316 191 948 8;
  • 29) 0.444 444 444 316 191 948 8 × 2 = 0 + 0.888 888 888 632 383 897 6;
  • 30) 0.888 888 888 632 383 897 6 × 2 = 1 + 0.777 777 777 264 767 795 2;
  • 31) 0.777 777 777 264 767 795 2 × 2 = 1 + 0.555 555 554 529 535 590 4;
  • 32) 0.555 555 554 529 535 590 4 × 2 = 1 + 0.111 111 109 059 071 180 8;
  • 33) 0.111 111 109 059 071 180 8 × 2 = 0 + 0.222 222 218 118 142 361 6;
  • 34) 0.222 222 218 118 142 361 6 × 2 = 0 + 0.444 444 436 236 284 723 2;
  • 35) 0.444 444 436 236 284 723 2 × 2 = 0 + 0.888 888 872 472 569 446 4;
  • 36) 0.888 888 872 472 569 446 4 × 2 = 1 + 0.777 777 744 945 138 892 8;
  • 37) 0.777 777 744 945 138 892 8 × 2 = 1 + 0.555 555 489 890 277 785 6;
  • 38) 0.555 555 489 890 277 785 6 × 2 = 1 + 0.111 110 979 780 555 571 2;
  • 39) 0.111 110 979 780 555 571 2 × 2 = 0 + 0.222 221 959 561 111 142 4;
  • 40) 0.222 221 959 561 111 142 4 × 2 = 0 + 0.444 443 919 122 222 284 8;
  • 41) 0.444 443 919 122 222 284 8 × 2 = 0 + 0.888 887 838 244 444 569 6;
  • 42) 0.888 887 838 244 444 569 6 × 2 = 1 + 0.777 775 676 488 889 139 2;
  • 43) 0.777 775 676 488 889 139 2 × 2 = 1 + 0.555 551 352 977 778 278 4;
  • 44) 0.555 551 352 977 778 278 4 × 2 = 1 + 0.111 102 705 955 556 556 8;
  • 45) 0.111 102 705 955 556 556 8 × 2 = 0 + 0.222 205 411 911 113 113 6;
  • 46) 0.222 205 411 911 113 113 6 × 2 = 0 + 0.444 410 823 822 226 227 2;
  • 47) 0.444 410 823 822 226 227 2 × 2 = 0 + 0.888 821 647 644 452 454 4;
  • 48) 0.888 821 647 644 452 454 4 × 2 = 1 + 0.777 643 295 288 904 908 8;
  • 49) 0.777 643 295 288 904 908 8 × 2 = 1 + 0.555 286 590 577 809 817 6;
  • 50) 0.555 286 590 577 809 817 6 × 2 = 1 + 0.110 573 181 155 619 635 2;
  • 51) 0.110 573 181 155 619 635 2 × 2 = 0 + 0.221 146 362 311 239 270 4;
  • 52) 0.221 146 362 311 239 270 4 × 2 = 0 + 0.442 292 724 622 478 540 8;
  • 53) 0.442 292 724 622 478 540 8 × 2 = 0 + 0.884 585 449 244 957 081 6;

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:


0.777 777 777 777 777 777 3(10) =


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

5. Positive number before normalization:

24.777 777 777 777 777 777 3(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:


24.777 777 777 777 777 777 3(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 24.777 777 777 777 777 777 3 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