24.777 777 777 777 777 777 617 Converted to 64 Bit Double Precision IEEE 754 Binary Floating Point Representation Standard

Convert decimal 24.777 777 777 777 777 777 617(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
24.777 777 777 777 777 777 617(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: 0.777 777 777 777 777 777 617.

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) 0.777 777 777 777 777 777 617 × 2 = 1 + 0.555 555 555 555 555 555 234;
  • 2) 0.555 555 555 555 555 555 234 × 2 = 1 + 0.111 111 111 111 111 110 468;
  • 3) 0.111 111 111 111 111 110 468 × 2 = 0 + 0.222 222 222 222 222 220 936;
  • 4) 0.222 222 222 222 222 220 936 × 2 = 0 + 0.444 444 444 444 444 441 872;
  • 5) 0.444 444 444 444 444 441 872 × 2 = 0 + 0.888 888 888 888 888 883 744;
  • 6) 0.888 888 888 888 888 883 744 × 2 = 1 + 0.777 777 777 777 777 767 488;
  • 7) 0.777 777 777 777 777 767 488 × 2 = 1 + 0.555 555 555 555 555 534 976;
  • 8) 0.555 555 555 555 555 534 976 × 2 = 1 + 0.111 111 111 111 111 069 952;
  • 9) 0.111 111 111 111 111 069 952 × 2 = 0 + 0.222 222 222 222 222 139 904;
  • 10) 0.222 222 222 222 222 139 904 × 2 = 0 + 0.444 444 444 444 444 279 808;
  • 11) 0.444 444 444 444 444 279 808 × 2 = 0 + 0.888 888 888 888 888 559 616;
  • 12) 0.888 888 888 888 888 559 616 × 2 = 1 + 0.777 777 777 777 777 119 232;
  • 13) 0.777 777 777 777 777 119 232 × 2 = 1 + 0.555 555 555 555 554 238 464;
  • 14) 0.555 555 555 555 554 238 464 × 2 = 1 + 0.111 111 111 111 108 476 928;
  • 15) 0.111 111 111 111 108 476 928 × 2 = 0 + 0.222 222 222 222 216 953 856;
  • 16) 0.222 222 222 222 216 953 856 × 2 = 0 + 0.444 444 444 444 433 907 712;
  • 17) 0.444 444 444 444 433 907 712 × 2 = 0 + 0.888 888 888 888 867 815 424;
  • 18) 0.888 888 888 888 867 815 424 × 2 = 1 + 0.777 777 777 777 735 630 848;
  • 19) 0.777 777 777 777 735 630 848 × 2 = 1 + 0.555 555 555 555 471 261 696;
  • 20) 0.555 555 555 555 471 261 696 × 2 = 1 + 0.111 111 111 110 942 523 392;
  • 21) 0.111 111 111 110 942 523 392 × 2 = 0 + 0.222 222 222 221 885 046 784;
  • 22) 0.222 222 222 221 885 046 784 × 2 = 0 + 0.444 444 444 443 770 093 568;
  • 23) 0.444 444 444 443 770 093 568 × 2 = 0 + 0.888 888 888 887 540 187 136;
  • 24) 0.888 888 888 887 540 187 136 × 2 = 1 + 0.777 777 777 775 080 374 272;
  • 25) 0.777 777 777 775 080 374 272 × 2 = 1 + 0.555 555 555 550 160 748 544;
  • 26) 0.555 555 555 550 160 748 544 × 2 = 1 + 0.111 111 111 100 321 497 088;
  • 27) 0.111 111 111 100 321 497 088 × 2 = 0 + 0.222 222 222 200 642 994 176;
  • 28) 0.222 222 222 200 642 994 176 × 2 = 0 + 0.444 444 444 401 285 988 352;
  • 29) 0.444 444 444 401 285 988 352 × 2 = 0 + 0.888 888 888 802 571 976 704;
  • 30) 0.888 888 888 802 571 976 704 × 2 = 1 + 0.777 777 777 605 143 953 408;
  • 31) 0.777 777 777 605 143 953 408 × 2 = 1 + 0.555 555 555 210 287 906 816;
  • 32) 0.555 555 555 210 287 906 816 × 2 = 1 + 0.111 111 110 420 575 813 632;
  • 33) 0.111 111 110 420 575 813 632 × 2 = 0 + 0.222 222 220 841 151 627 264;
  • 34) 0.222 222 220 841 151 627 264 × 2 = 0 + 0.444 444 441 682 303 254 528;
  • 35) 0.444 444 441 682 303 254 528 × 2 = 0 + 0.888 888 883 364 606 509 056;
  • 36) 0.888 888 883 364 606 509 056 × 2 = 1 + 0.777 777 766 729 213 018 112;
  • 37) 0.777 777 766 729 213 018 112 × 2 = 1 + 0.555 555 533 458 426 036 224;
  • 38) 0.555 555 533 458 426 036 224 × 2 = 1 + 0.111 111 066 916 852 072 448;
  • 39) 0.111 111 066 916 852 072 448 × 2 = 0 + 0.222 222 133 833 704 144 896;
  • 40) 0.222 222 133 833 704 144 896 × 2 = 0 + 0.444 444 267 667 408 289 792;
  • 41) 0.444 444 267 667 408 289 792 × 2 = 0 + 0.888 888 535 334 816 579 584;
  • 42) 0.888 888 535 334 816 579 584 × 2 = 1 + 0.777 777 070 669 633 159 168;
  • 43) 0.777 777 070 669 633 159 168 × 2 = 1 + 0.555 554 141 339 266 318 336;
  • 44) 0.555 554 141 339 266 318 336 × 2 = 1 + 0.111 108 282 678 532 636 672;
  • 45) 0.111 108 282 678 532 636 672 × 2 = 0 + 0.222 216 565 357 065 273 344;
  • 46) 0.222 216 565 357 065 273 344 × 2 = 0 + 0.444 433 130 714 130 546 688;
  • 47) 0.444 433 130 714 130 546 688 × 2 = 0 + 0.888 866 261 428 261 093 376;
  • 48) 0.888 866 261 428 261 093 376 × 2 = 1 + 0.777 732 522 856 522 186 752;
  • 49) 0.777 732 522 856 522 186 752 × 2 = 1 + 0.555 465 045 713 044 373 504;
  • 50) 0.555 465 045 713 044 373 504 × 2 = 1 + 0.110 930 091 426 088 747 008;
  • 51) 0.110 930 091 426 088 747 008 × 2 = 0 + 0.221 860 182 852 177 494 016;
  • 52) 0.221 860 182 852 177 494 016 × 2 = 0 + 0.443 720 365 704 354 988 032;
  • 53) 0.443 720 365 704 354 988 032 × 2 = 0 + 0.887 440 731 408 709 976 064;

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:


0.777 777 777 777 777 777 617(10) =


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

5. Positive number before normalization:

24.777 777 777 777 777 777 617(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:


24.777 777 777 777 777 777 617(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 24.777 777 777 777 777 777 617 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