24.777 777 777 777 777 774 7 Converted to 64 Bit Double Precision IEEE 754 Binary Floating Point Representation Standard

Convert decimal 24.777 777 777 777 777 774 7(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
24.777 777 777 777 777 774 7(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: 0.777 777 777 777 777 774 7.

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) 0.777 777 777 777 777 774 7 × 2 = 1 + 0.555 555 555 555 555 549 4;
  • 2) 0.555 555 555 555 555 549 4 × 2 = 1 + 0.111 111 111 111 111 098 8;
  • 3) 0.111 111 111 111 111 098 8 × 2 = 0 + 0.222 222 222 222 222 197 6;
  • 4) 0.222 222 222 222 222 197 6 × 2 = 0 + 0.444 444 444 444 444 395 2;
  • 5) 0.444 444 444 444 444 395 2 × 2 = 0 + 0.888 888 888 888 888 790 4;
  • 6) 0.888 888 888 888 888 790 4 × 2 = 1 + 0.777 777 777 777 777 580 8;
  • 7) 0.777 777 777 777 777 580 8 × 2 = 1 + 0.555 555 555 555 555 161 6;
  • 8) 0.555 555 555 555 555 161 6 × 2 = 1 + 0.111 111 111 111 110 323 2;
  • 9) 0.111 111 111 111 110 323 2 × 2 = 0 + 0.222 222 222 222 220 646 4;
  • 10) 0.222 222 222 222 220 646 4 × 2 = 0 + 0.444 444 444 444 441 292 8;
  • 11) 0.444 444 444 444 441 292 8 × 2 = 0 + 0.888 888 888 888 882 585 6;
  • 12) 0.888 888 888 888 882 585 6 × 2 = 1 + 0.777 777 777 777 765 171 2;
  • 13) 0.777 777 777 777 765 171 2 × 2 = 1 + 0.555 555 555 555 530 342 4;
  • 14) 0.555 555 555 555 530 342 4 × 2 = 1 + 0.111 111 111 111 060 684 8;
  • 15) 0.111 111 111 111 060 684 8 × 2 = 0 + 0.222 222 222 222 121 369 6;
  • 16) 0.222 222 222 222 121 369 6 × 2 = 0 + 0.444 444 444 444 242 739 2;
  • 17) 0.444 444 444 444 242 739 2 × 2 = 0 + 0.888 888 888 888 485 478 4;
  • 18) 0.888 888 888 888 485 478 4 × 2 = 1 + 0.777 777 777 776 970 956 8;
  • 19) 0.777 777 777 776 970 956 8 × 2 = 1 + 0.555 555 555 553 941 913 6;
  • 20) 0.555 555 555 553 941 913 6 × 2 = 1 + 0.111 111 111 107 883 827 2;
  • 21) 0.111 111 111 107 883 827 2 × 2 = 0 + 0.222 222 222 215 767 654 4;
  • 22) 0.222 222 222 215 767 654 4 × 2 = 0 + 0.444 444 444 431 535 308 8;
  • 23) 0.444 444 444 431 535 308 8 × 2 = 0 + 0.888 888 888 863 070 617 6;
  • 24) 0.888 888 888 863 070 617 6 × 2 = 1 + 0.777 777 777 726 141 235 2;
  • 25) 0.777 777 777 726 141 235 2 × 2 = 1 + 0.555 555 555 452 282 470 4;
  • 26) 0.555 555 555 452 282 470 4 × 2 = 1 + 0.111 111 110 904 564 940 8;
  • 27) 0.111 111 110 904 564 940 8 × 2 = 0 + 0.222 222 221 809 129 881 6;
  • 28) 0.222 222 221 809 129 881 6 × 2 = 0 + 0.444 444 443 618 259 763 2;
  • 29) 0.444 444 443 618 259 763 2 × 2 = 0 + 0.888 888 887 236 519 526 4;
  • 30) 0.888 888 887 236 519 526 4 × 2 = 1 + 0.777 777 774 473 039 052 8;
  • 31) 0.777 777 774 473 039 052 8 × 2 = 1 + 0.555 555 548 946 078 105 6;
  • 32) 0.555 555 548 946 078 105 6 × 2 = 1 + 0.111 111 097 892 156 211 2;
  • 33) 0.111 111 097 892 156 211 2 × 2 = 0 + 0.222 222 195 784 312 422 4;
  • 34) 0.222 222 195 784 312 422 4 × 2 = 0 + 0.444 444 391 568 624 844 8;
  • 35) 0.444 444 391 568 624 844 8 × 2 = 0 + 0.888 888 783 137 249 689 6;
  • 36) 0.888 888 783 137 249 689 6 × 2 = 1 + 0.777 777 566 274 499 379 2;
  • 37) 0.777 777 566 274 499 379 2 × 2 = 1 + 0.555 555 132 548 998 758 4;
  • 38) 0.555 555 132 548 998 758 4 × 2 = 1 + 0.111 110 265 097 997 516 8;
  • 39) 0.111 110 265 097 997 516 8 × 2 = 0 + 0.222 220 530 195 995 033 6;
  • 40) 0.222 220 530 195 995 033 6 × 2 = 0 + 0.444 441 060 391 990 067 2;
  • 41) 0.444 441 060 391 990 067 2 × 2 = 0 + 0.888 882 120 783 980 134 4;
  • 42) 0.888 882 120 783 980 134 4 × 2 = 1 + 0.777 764 241 567 960 268 8;
  • 43) 0.777 764 241 567 960 268 8 × 2 = 1 + 0.555 528 483 135 920 537 6;
  • 44) 0.555 528 483 135 920 537 6 × 2 = 1 + 0.111 056 966 271 841 075 2;
  • 45) 0.111 056 966 271 841 075 2 × 2 = 0 + 0.222 113 932 543 682 150 4;
  • 46) 0.222 113 932 543 682 150 4 × 2 = 0 + 0.444 227 865 087 364 300 8;
  • 47) 0.444 227 865 087 364 300 8 × 2 = 0 + 0.888 455 730 174 728 601 6;
  • 48) 0.888 455 730 174 728 601 6 × 2 = 1 + 0.776 911 460 349 457 203 2;
  • 49) 0.776 911 460 349 457 203 2 × 2 = 1 + 0.553 822 920 698 914 406 4;
  • 50) 0.553 822 920 698 914 406 4 × 2 = 1 + 0.107 645 841 397 828 812 8;
  • 51) 0.107 645 841 397 828 812 8 × 2 = 0 + 0.215 291 682 795 657 625 6;
  • 52) 0.215 291 682 795 657 625 6 × 2 = 0 + 0.430 583 365 591 315 251 2;
  • 53) 0.430 583 365 591 315 251 2 × 2 = 0 + 0.861 166 731 182 630 502 4;

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:


0.777 777 777 777 777 774 7(10) =


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

5. Positive number before normalization:

24.777 777 777 777 777 774 7(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:


24.777 777 777 777 777 774 7(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 24.777 777 777 777 777 774 7 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