-0.066 298 275 65 Converted to 64 Bit Double Precision IEEE 754 Binary Floating Point Representation Standard

Convert decimal -0.066 298 275 65(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
-0.066 298 275 65(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:

|-0.066 298 275 65| = 0.066 298 275 65


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: 0.066 298 275 65.

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) 0.066 298 275 65 × 2 = 0 + 0.132 596 551 3;
  • 2) 0.132 596 551 3 × 2 = 0 + 0.265 193 102 6;
  • 3) 0.265 193 102 6 × 2 = 0 + 0.530 386 205 2;
  • 4) 0.530 386 205 2 × 2 = 1 + 0.060 772 410 4;
  • 5) 0.060 772 410 4 × 2 = 0 + 0.121 544 820 8;
  • 6) 0.121 544 820 8 × 2 = 0 + 0.243 089 641 6;
  • 7) 0.243 089 641 6 × 2 = 0 + 0.486 179 283 2;
  • 8) 0.486 179 283 2 × 2 = 0 + 0.972 358 566 4;
  • 9) 0.972 358 566 4 × 2 = 1 + 0.944 717 132 8;
  • 10) 0.944 717 132 8 × 2 = 1 + 0.889 434 265 6;
  • 11) 0.889 434 265 6 × 2 = 1 + 0.778 868 531 2;
  • 12) 0.778 868 531 2 × 2 = 1 + 0.557 737 062 4;
  • 13) 0.557 737 062 4 × 2 = 1 + 0.115 474 124 8;
  • 14) 0.115 474 124 8 × 2 = 0 + 0.230 948 249 6;
  • 15) 0.230 948 249 6 × 2 = 0 + 0.461 896 499 2;
  • 16) 0.461 896 499 2 × 2 = 0 + 0.923 792 998 4;
  • 17) 0.923 792 998 4 × 2 = 1 + 0.847 585 996 8;
  • 18) 0.847 585 996 8 × 2 = 1 + 0.695 171 993 6;
  • 19) 0.695 171 993 6 × 2 = 1 + 0.390 343 987 2;
  • 20) 0.390 343 987 2 × 2 = 0 + 0.780 687 974 4;
  • 21) 0.780 687 974 4 × 2 = 1 + 0.561 375 948 8;
  • 22) 0.561 375 948 8 × 2 = 1 + 0.122 751 897 6;
  • 23) 0.122 751 897 6 × 2 = 0 + 0.245 503 795 2;
  • 24) 0.245 503 795 2 × 2 = 0 + 0.491 007 590 4;
  • 25) 0.491 007 590 4 × 2 = 0 + 0.982 015 180 8;
  • 26) 0.982 015 180 8 × 2 = 1 + 0.964 030 361 6;
  • 27) 0.964 030 361 6 × 2 = 1 + 0.928 060 723 2;
  • 28) 0.928 060 723 2 × 2 = 1 + 0.856 121 446 4;
  • 29) 0.856 121 446 4 × 2 = 1 + 0.712 242 892 8;
  • 30) 0.712 242 892 8 × 2 = 1 + 0.424 485 785 6;
  • 31) 0.424 485 785 6 × 2 = 0 + 0.848 971 571 2;
  • 32) 0.848 971 571 2 × 2 = 1 + 0.697 943 142 4;
  • 33) 0.697 943 142 4 × 2 = 1 + 0.395 886 284 8;
  • 34) 0.395 886 284 8 × 2 = 0 + 0.791 772 569 6;
  • 35) 0.791 772 569 6 × 2 = 1 + 0.583 545 139 2;
  • 36) 0.583 545 139 2 × 2 = 1 + 0.167 090 278 4;
  • 37) 0.167 090 278 4 × 2 = 0 + 0.334 180 556 8;
  • 38) 0.334 180 556 8 × 2 = 0 + 0.668 361 113 6;
  • 39) 0.668 361 113 6 × 2 = 1 + 0.336 722 227 2;
  • 40) 0.336 722 227 2 × 2 = 0 + 0.673 444 454 4;
  • 41) 0.673 444 454 4 × 2 = 1 + 0.346 888 908 8;
  • 42) 0.346 888 908 8 × 2 = 0 + 0.693 777 817 6;
  • 43) 0.693 777 817 6 × 2 = 1 + 0.387 555 635 2;
  • 44) 0.387 555 635 2 × 2 = 0 + 0.775 111 270 4;
  • 45) 0.775 111 270 4 × 2 = 1 + 0.550 222 540 8;
  • 46) 0.550 222 540 8 × 2 = 1 + 0.100 445 081 6;
  • 47) 0.100 445 081 6 × 2 = 0 + 0.200 890 163 2;
  • 48) 0.200 890 163 2 × 2 = 0 + 0.401 780 326 4;
  • 49) 0.401 780 326 4 × 2 = 0 + 0.803 560 652 8;
  • 50) 0.803 560 652 8 × 2 = 1 + 0.607 121 305 6;
  • 51) 0.607 121 305 6 × 2 = 1 + 0.214 242 611 2;
  • 52) 0.214 242 611 2 × 2 = 0 + 0.428 485 222 4;
  • 53) 0.428 485 222 4 × 2 = 0 + 0.856 970 444 8;
  • 54) 0.856 970 444 8 × 2 = 1 + 0.713 940 889 6;
  • 55) 0.713 940 889 6 × 2 = 1 + 0.427 881 779 2;
  • 56) 0.427 881 779 2 × 2 = 0 + 0.855 763 558 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).


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:


0.066 298 275 65(10) =

0.0001 0000 1111 1000 1110 1100 0111 1101 1011 0010 1010 1100 0110 0110(2)

6. Positive number before normalization:

0.066 298 275 65(10) =

0.0001 0000 1111 1000 1110 1100 0111 1101 1011 0010 1010 1100 0110 0110(2)

7. Normalize the binary representation of the number.

Shift the decimal mark 4 positions to the right, so that only one non zero digit remains to the left of it:


0.066 298 275 65(10) =

0.0001 0000 1111 1000 1110 1100 0111 1101 1011 0010 1010 1100 0110 0110(2) =

0.0001 0000 1111 1000 1110 1100 0111 1101 1011 0010 1010 1100 0110 0110(2) × 20 =

1.0000 1111 1000 1110 1100 0111 1101 1011 0010 1010 1100 0110 0110(2) × 2-4


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):
1.0000 1111 1000 1110 1100 0111 1101 1011 0010 1010 1100 0110 0110


9. 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) =

1 019(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;
  • 1 019 ÷ 2 = 509 + 1;
  • 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) =

1019(10) =

011 1111 1011(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. 0000 1111 1000 1110 1100 0111 1101 1011 0010 1010 1100 0110 0110 =

0000 1111 1000 1110 1100 0111 1101 1011 0010 1010 1100 0110 0110


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 1011

Mantissa (52 bits) =
0000 1111 1000 1110 1100 0111 1101 1011 0010 1010 1100 0110 0110


Decimal number -0.066 298 275 65 converted to 64 bit double precision IEEE 754 binary floating point representation:

1 - 011 1111 1011 - 0000 1111 1000 1110 1100 0111 1101 1011 0010 1010 1100 0110 0110

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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