-0.056 981 8 Converted to 64 Bit Double Precision IEEE 754 Binary Floating Point Representation Standard

Convert decimal -0.056 981 8(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
-0.056 981 8(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. Start with the positive version of the number:

|-0.056 981 8| = 0.056 981 8


2. First, convert to binary (in base 2) the integer part: 0.
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;
  • 0 ÷ 2 = 0 + 0;

3. 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.

0(10) =


0(2)


4. Convert to binary (base 2) the fractional part: 0.056 981 8.

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) 0.056 981 8 × 2 = 0 + 0.113 963 6;
  • 2) 0.113 963 6 × 2 = 0 + 0.227 927 2;
  • 3) 0.227 927 2 × 2 = 0 + 0.455 854 4;
  • 4) 0.455 854 4 × 2 = 0 + 0.911 708 8;
  • 5) 0.911 708 8 × 2 = 1 + 0.823 417 6;
  • 6) 0.823 417 6 × 2 = 1 + 0.646 835 2;
  • 7) 0.646 835 2 × 2 = 1 + 0.293 670 4;
  • 8) 0.293 670 4 × 2 = 0 + 0.587 340 8;
  • 9) 0.587 340 8 × 2 = 1 + 0.174 681 6;
  • 10) 0.174 681 6 × 2 = 0 + 0.349 363 2;
  • 11) 0.349 363 2 × 2 = 0 + 0.698 726 4;
  • 12) 0.698 726 4 × 2 = 1 + 0.397 452 8;
  • 13) 0.397 452 8 × 2 = 0 + 0.794 905 6;
  • 14) 0.794 905 6 × 2 = 1 + 0.589 811 2;
  • 15) 0.589 811 2 × 2 = 1 + 0.179 622 4;
  • 16) 0.179 622 4 × 2 = 0 + 0.359 244 8;
  • 17) 0.359 244 8 × 2 = 0 + 0.718 489 6;
  • 18) 0.718 489 6 × 2 = 1 + 0.436 979 2;
  • 19) 0.436 979 2 × 2 = 0 + 0.873 958 4;
  • 20) 0.873 958 4 × 2 = 1 + 0.747 916 8;
  • 21) 0.747 916 8 × 2 = 1 + 0.495 833 6;
  • 22) 0.495 833 6 × 2 = 0 + 0.991 667 2;
  • 23) 0.991 667 2 × 2 = 1 + 0.983 334 4;
  • 24) 0.983 334 4 × 2 = 1 + 0.966 668 8;
  • 25) 0.966 668 8 × 2 = 1 + 0.933 337 6;
  • 26) 0.933 337 6 × 2 = 1 + 0.866 675 2;
  • 27) 0.866 675 2 × 2 = 1 + 0.733 350 4;
  • 28) 0.733 350 4 × 2 = 1 + 0.466 700 8;
  • 29) 0.466 700 8 × 2 = 0 + 0.933 401 6;
  • 30) 0.933 401 6 × 2 = 1 + 0.866 803 2;
  • 31) 0.866 803 2 × 2 = 1 + 0.733 606 4;
  • 32) 0.733 606 4 × 2 = 1 + 0.467 212 8;
  • 33) 0.467 212 8 × 2 = 0 + 0.934 425 6;
  • 34) 0.934 425 6 × 2 = 1 + 0.868 851 2;
  • 35) 0.868 851 2 × 2 = 1 + 0.737 702 4;
  • 36) 0.737 702 4 × 2 = 1 + 0.475 404 8;
  • 37) 0.475 404 8 × 2 = 0 + 0.950 809 6;
  • 38) 0.950 809 6 × 2 = 1 + 0.901 619 2;
  • 39) 0.901 619 2 × 2 = 1 + 0.803 238 4;
  • 40) 0.803 238 4 × 2 = 1 + 0.606 476 8;
  • 41) 0.606 476 8 × 2 = 1 + 0.212 953 6;
  • 42) 0.212 953 6 × 2 = 0 + 0.425 907 2;
  • 43) 0.425 907 2 × 2 = 0 + 0.851 814 4;
  • 44) 0.851 814 4 × 2 = 1 + 0.703 628 8;
  • 45) 0.703 628 8 × 2 = 1 + 0.407 257 6;
  • 46) 0.407 257 6 × 2 = 0 + 0.814 515 2;
  • 47) 0.814 515 2 × 2 = 1 + 0.629 030 4;
  • 48) 0.629 030 4 × 2 = 1 + 0.258 060 8;
  • 49) 0.258 060 8 × 2 = 0 + 0.516 121 6;
  • 50) 0.516 121 6 × 2 = 1 + 0.032 243 2;
  • 51) 0.032 243 2 × 2 = 0 + 0.064 486 4;
  • 52) 0.064 486 4 × 2 = 0 + 0.128 972 8;
  • 53) 0.128 972 8 × 2 = 0 + 0.257 945 6;
  • 54) 0.257 945 6 × 2 = 0 + 0.515 891 2;
  • 55) 0.515 891 2 × 2 = 1 + 0.031 782 4;
  • 56) 0.031 782 4 × 2 = 0 + 0.063 564 8;
  • 57) 0.063 564 8 × 2 = 0 + 0.127 129 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).


5. 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:


0.056 981 8(10) =


0.0000 1110 1001 0110 0101 1011 1111 0111 0111 0111 1001 1011 0100 0010 0(2)

6. Positive number before normalization:

0.056 981 8(10) =


0.0000 1110 1001 0110 0101 1011 1111 0111 0111 0111 1001 1011 0100 0010 0(2)

7. Normalize the binary representation of the number.

Shift the decimal mark 5 positions to the right, so that only one non zero digit remains to the left of it:


0.056 981 8(10) =


0.0000 1110 1001 0110 0101 1011 1111 0111 0111 0111 1001 1011 0100 0010 0(2) =


0.0000 1110 1001 0110 0101 1011 1111 0111 0111 0111 1001 1011 0100 0010 0(2) × 20 =


1.1101 0010 1100 1011 0111 1110 1110 1110 1111 0011 0110 1000 0100(2) × 2-5


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): -5


Mantissa (not normalized):
1.1101 0010 1100 1011 0111 1110 1110 1110 1111 0011 0110 1000 0100


9. Adjust the exponent.

Use the 11 bit excess/bias notation:


Exponent (adjusted) =


Exponent (unadjusted) + 2(11-1) - 1 =


-5 + 2(11-1) - 1 =


(-5 + 1 023)(10) =


1 018(10)


10. 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;
  • 1 018 ÷ 2 = 509 + 0;
  • 509 ÷ 2 = 254 + 1;
  • 254 ÷ 2 = 127 + 0;
  • 127 ÷ 2 = 63 + 1;
  • 63 ÷ 2 = 31 + 1;
  • 31 ÷ 2 = 15 + 1;
  • 15 ÷ 2 = 7 + 1;
  • 7 ÷ 2 = 3 + 1;
  • 3 ÷ 2 = 1 + 1;
  • 1 ÷ 2 = 0 + 1;

11. Construct the base 2 representation of the adjusted exponent.

Take all the remainders starting from the bottom of the list constructed above.


Exponent (adjusted) =


1018(10) =


011 1111 1010(2)


12. 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, only if necessary (not the case here).


Mantissa (normalized) =


1. 1101 0010 1100 1011 0111 1110 1110 1110 1111 0011 0110 1000 0100 =


1101 0010 1100 1011 0111 1110 1110 1110 1111 0011 0110 1000 0100


13. The three elements that make up the number's 64 bit double precision IEEE 754 binary floating point representation:

Sign (1 bit) =
1 (a negative number)


Exponent (11 bits) =
011 1111 1010


Mantissa (52 bits) =
1101 0010 1100 1011 0111 1110 1110 1110 1111 0011 0110 1000 0100


Decimal number -0.056 981 8 converted to 64 bit double precision IEEE 754 binary floating point representation:

1 - 011 1111 1010 - 1101 0010 1100 1011 0111 1110 1110 1110 1111 0011 0110 1000 0100


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