24.777 777 777 777 777 777 552 Converted to 64 Bit Double Precision IEEE 754 Binary Floating Point Representation Standard

Convert decimal 24.777 777 777 777 777 777 552(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
24.777 777 777 777 777 777 552(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: 0.777 777 777 777 777 777 552.

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) 0.777 777 777 777 777 777 552 × 2 = 1 + 0.555 555 555 555 555 555 104;
  • 2) 0.555 555 555 555 555 555 104 × 2 = 1 + 0.111 111 111 111 111 110 208;
  • 3) 0.111 111 111 111 111 110 208 × 2 = 0 + 0.222 222 222 222 222 220 416;
  • 4) 0.222 222 222 222 222 220 416 × 2 = 0 + 0.444 444 444 444 444 440 832;
  • 5) 0.444 444 444 444 444 440 832 × 2 = 0 + 0.888 888 888 888 888 881 664;
  • 6) 0.888 888 888 888 888 881 664 × 2 = 1 + 0.777 777 777 777 777 763 328;
  • 7) 0.777 777 777 777 777 763 328 × 2 = 1 + 0.555 555 555 555 555 526 656;
  • 8) 0.555 555 555 555 555 526 656 × 2 = 1 + 0.111 111 111 111 111 053 312;
  • 9) 0.111 111 111 111 111 053 312 × 2 = 0 + 0.222 222 222 222 222 106 624;
  • 10) 0.222 222 222 222 222 106 624 × 2 = 0 + 0.444 444 444 444 444 213 248;
  • 11) 0.444 444 444 444 444 213 248 × 2 = 0 + 0.888 888 888 888 888 426 496;
  • 12) 0.888 888 888 888 888 426 496 × 2 = 1 + 0.777 777 777 777 776 852 992;
  • 13) 0.777 777 777 777 776 852 992 × 2 = 1 + 0.555 555 555 555 553 705 984;
  • 14) 0.555 555 555 555 553 705 984 × 2 = 1 + 0.111 111 111 111 107 411 968;
  • 15) 0.111 111 111 111 107 411 968 × 2 = 0 + 0.222 222 222 222 214 823 936;
  • 16) 0.222 222 222 222 214 823 936 × 2 = 0 + 0.444 444 444 444 429 647 872;
  • 17) 0.444 444 444 444 429 647 872 × 2 = 0 + 0.888 888 888 888 859 295 744;
  • 18) 0.888 888 888 888 859 295 744 × 2 = 1 + 0.777 777 777 777 718 591 488;
  • 19) 0.777 777 777 777 718 591 488 × 2 = 1 + 0.555 555 555 555 437 182 976;
  • 20) 0.555 555 555 555 437 182 976 × 2 = 1 + 0.111 111 111 110 874 365 952;
  • 21) 0.111 111 111 110 874 365 952 × 2 = 0 + 0.222 222 222 221 748 731 904;
  • 22) 0.222 222 222 221 748 731 904 × 2 = 0 + 0.444 444 444 443 497 463 808;
  • 23) 0.444 444 444 443 497 463 808 × 2 = 0 + 0.888 888 888 886 994 927 616;
  • 24) 0.888 888 888 886 994 927 616 × 2 = 1 + 0.777 777 777 773 989 855 232;
  • 25) 0.777 777 777 773 989 855 232 × 2 = 1 + 0.555 555 555 547 979 710 464;
  • 26) 0.555 555 555 547 979 710 464 × 2 = 1 + 0.111 111 111 095 959 420 928;
  • 27) 0.111 111 111 095 959 420 928 × 2 = 0 + 0.222 222 222 191 918 841 856;
  • 28) 0.222 222 222 191 918 841 856 × 2 = 0 + 0.444 444 444 383 837 683 712;
  • 29) 0.444 444 444 383 837 683 712 × 2 = 0 + 0.888 888 888 767 675 367 424;
  • 30) 0.888 888 888 767 675 367 424 × 2 = 1 + 0.777 777 777 535 350 734 848;
  • 31) 0.777 777 777 535 350 734 848 × 2 = 1 + 0.555 555 555 070 701 469 696;
  • 32) 0.555 555 555 070 701 469 696 × 2 = 1 + 0.111 111 110 141 402 939 392;
  • 33) 0.111 111 110 141 402 939 392 × 2 = 0 + 0.222 222 220 282 805 878 784;
  • 34) 0.222 222 220 282 805 878 784 × 2 = 0 + 0.444 444 440 565 611 757 568;
  • 35) 0.444 444 440 565 611 757 568 × 2 = 0 + 0.888 888 881 131 223 515 136;
  • 36) 0.888 888 881 131 223 515 136 × 2 = 1 + 0.777 777 762 262 447 030 272;
  • 37) 0.777 777 762 262 447 030 272 × 2 = 1 + 0.555 555 524 524 894 060 544;
  • 38) 0.555 555 524 524 894 060 544 × 2 = 1 + 0.111 111 049 049 788 121 088;
  • 39) 0.111 111 049 049 788 121 088 × 2 = 0 + 0.222 222 098 099 576 242 176;
  • 40) 0.222 222 098 099 576 242 176 × 2 = 0 + 0.444 444 196 199 152 484 352;
  • 41) 0.444 444 196 199 152 484 352 × 2 = 0 + 0.888 888 392 398 304 968 704;
  • 42) 0.888 888 392 398 304 968 704 × 2 = 1 + 0.777 776 784 796 609 937 408;
  • 43) 0.777 776 784 796 609 937 408 × 2 = 1 + 0.555 553 569 593 219 874 816;
  • 44) 0.555 553 569 593 219 874 816 × 2 = 1 + 0.111 107 139 186 439 749 632;
  • 45) 0.111 107 139 186 439 749 632 × 2 = 0 + 0.222 214 278 372 879 499 264;
  • 46) 0.222 214 278 372 879 499 264 × 2 = 0 + 0.444 428 556 745 758 998 528;
  • 47) 0.444 428 556 745 758 998 528 × 2 = 0 + 0.888 857 113 491 517 997 056;
  • 48) 0.888 857 113 491 517 997 056 × 2 = 1 + 0.777 714 226 983 035 994 112;
  • 49) 0.777 714 226 983 035 994 112 × 2 = 1 + 0.555 428 453 966 071 988 224;
  • 50) 0.555 428 453 966 071 988 224 × 2 = 1 + 0.110 856 907 932 143 976 448;
  • 51) 0.110 856 907 932 143 976 448 × 2 = 0 + 0.221 713 815 864 287 952 896;
  • 52) 0.221 713 815 864 287 952 896 × 2 = 0 + 0.443 427 631 728 575 905 792;
  • 53) 0.443 427 631 728 575 905 792 × 2 = 0 + 0.886 855 263 457 151 811 584;

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:


0.777 777 777 777 777 777 552(10) =


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

5. Positive number before normalization:

24.777 777 777 777 777 777 552(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:


24.777 777 777 777 777 777 552(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 24.777 777 777 777 777 777 552 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