24.777 777 777 777 818 Converted to 64 Bit Double Precision IEEE 754 Binary Floating Point Representation Standard

Convert decimal 24.777 777 777 777 818(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
24.777 777 777 777 818(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: 0.777 777 777 777 818.

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) 0.777 777 777 777 818 × 2 = 1 + 0.555 555 555 555 636;
  • 2) 0.555 555 555 555 636 × 2 = 1 + 0.111 111 111 111 272;
  • 3) 0.111 111 111 111 272 × 2 = 0 + 0.222 222 222 222 544;
  • 4) 0.222 222 222 222 544 × 2 = 0 + 0.444 444 444 445 088;
  • 5) 0.444 444 444 445 088 × 2 = 0 + 0.888 888 888 890 176;
  • 6) 0.888 888 888 890 176 × 2 = 1 + 0.777 777 777 780 352;
  • 7) 0.777 777 777 780 352 × 2 = 1 + 0.555 555 555 560 704;
  • 8) 0.555 555 555 560 704 × 2 = 1 + 0.111 111 111 121 408;
  • 9) 0.111 111 111 121 408 × 2 = 0 + 0.222 222 222 242 816;
  • 10) 0.222 222 222 242 816 × 2 = 0 + 0.444 444 444 485 632;
  • 11) 0.444 444 444 485 632 × 2 = 0 + 0.888 888 888 971 264;
  • 12) 0.888 888 888 971 264 × 2 = 1 + 0.777 777 777 942 528;
  • 13) 0.777 777 777 942 528 × 2 = 1 + 0.555 555 555 885 056;
  • 14) 0.555 555 555 885 056 × 2 = 1 + 0.111 111 111 770 112;
  • 15) 0.111 111 111 770 112 × 2 = 0 + 0.222 222 223 540 224;
  • 16) 0.222 222 223 540 224 × 2 = 0 + 0.444 444 447 080 448;
  • 17) 0.444 444 447 080 448 × 2 = 0 + 0.888 888 894 160 896;
  • 18) 0.888 888 894 160 896 × 2 = 1 + 0.777 777 788 321 792;
  • 19) 0.777 777 788 321 792 × 2 = 1 + 0.555 555 576 643 584;
  • 20) 0.555 555 576 643 584 × 2 = 1 + 0.111 111 153 287 168;
  • 21) 0.111 111 153 287 168 × 2 = 0 + 0.222 222 306 574 336;
  • 22) 0.222 222 306 574 336 × 2 = 0 + 0.444 444 613 148 672;
  • 23) 0.444 444 613 148 672 × 2 = 0 + 0.888 889 226 297 344;
  • 24) 0.888 889 226 297 344 × 2 = 1 + 0.777 778 452 594 688;
  • 25) 0.777 778 452 594 688 × 2 = 1 + 0.555 556 905 189 376;
  • 26) 0.555 556 905 189 376 × 2 = 1 + 0.111 113 810 378 752;
  • 27) 0.111 113 810 378 752 × 2 = 0 + 0.222 227 620 757 504;
  • 28) 0.222 227 620 757 504 × 2 = 0 + 0.444 455 241 515 008;
  • 29) 0.444 455 241 515 008 × 2 = 0 + 0.888 910 483 030 016;
  • 30) 0.888 910 483 030 016 × 2 = 1 + 0.777 820 966 060 032;
  • 31) 0.777 820 966 060 032 × 2 = 1 + 0.555 641 932 120 064;
  • 32) 0.555 641 932 120 064 × 2 = 1 + 0.111 283 864 240 128;
  • 33) 0.111 283 864 240 128 × 2 = 0 + 0.222 567 728 480 256;
  • 34) 0.222 567 728 480 256 × 2 = 0 + 0.445 135 456 960 512;
  • 35) 0.445 135 456 960 512 × 2 = 0 + 0.890 270 913 921 024;
  • 36) 0.890 270 913 921 024 × 2 = 1 + 0.780 541 827 842 048;
  • 37) 0.780 541 827 842 048 × 2 = 1 + 0.561 083 655 684 096;
  • 38) 0.561 083 655 684 096 × 2 = 1 + 0.122 167 311 368 192;
  • 39) 0.122 167 311 368 192 × 2 = 0 + 0.244 334 622 736 384;
  • 40) 0.244 334 622 736 384 × 2 = 0 + 0.488 669 245 472 768;
  • 41) 0.488 669 245 472 768 × 2 = 0 + 0.977 338 490 945 536;
  • 42) 0.977 338 490 945 536 × 2 = 1 + 0.954 676 981 891 072;
  • 43) 0.954 676 981 891 072 × 2 = 1 + 0.909 353 963 782 144;
  • 44) 0.909 353 963 782 144 × 2 = 1 + 0.818 707 927 564 288;
  • 45) 0.818 707 927 564 288 × 2 = 1 + 0.637 415 855 128 576;
  • 46) 0.637 415 855 128 576 × 2 = 1 + 0.274 831 710 257 152;
  • 47) 0.274 831 710 257 152 × 2 = 0 + 0.549 663 420 514 304;
  • 48) 0.549 663 420 514 304 × 2 = 1 + 0.099 326 841 028 608;
  • 49) 0.099 326 841 028 608 × 2 = 0 + 0.198 653 682 057 216;
  • 50) 0.198 653 682 057 216 × 2 = 0 + 0.397 307 364 114 432;
  • 51) 0.397 307 364 114 432 × 2 = 0 + 0.794 614 728 228 864;
  • 52) 0.794 614 728 228 864 × 2 = 1 + 0.589 229 456 457 728;
  • 53) 0.589 229 456 457 728 × 2 = 1 + 0.178 458 912 915 456;

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:


0.777 777 777 777 818(10) =


0.1100 0111 0001 1100 0111 0001 1100 0111 0001 1100 0111 1101 0001 1(2)

5. Positive number before normalization:

24.777 777 777 777 818(10) =


1 1000.1100 0111 0001 1100 0111 0001 1100 0111 0001 1100 0111 1101 0001 1(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:


24.777 777 777 777 818(10) =


1 1000.1100 0111 0001 1100 0111 0001 1100 0111 0001 1100 0111 1101 0001 1(2) =


1 1000.1100 0111 0001 1100 0111 0001 1100 0111 0001 1100 0111 1101 0001 1(2) × 20 =


1.1000 1100 0111 0001 1100 0111 0001 1100 0111 0001 1100 0111 1101 0001 1(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 1101 0001 1


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 1101 0 0011 =


1000 1100 0111 0001 1100 0111 0001 1100 0111 0001 1100 0111 1101


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 1101


Decimal number 24.777 777 777 777 818 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 1101


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