0.487 236 727 Converted to 64 Bit Double Precision IEEE 754 Binary Floating Point Representation Standard

Convert decimal 0.487 236 727(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
0.487 236 727(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: 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;

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.

0(10) =

0(2)


3. Convert to binary (base 2) the fractional part: 0.487 236 727.

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) 0.487 236 727 × 2 = 0 + 0.974 473 454;
  • 2) 0.974 473 454 × 2 = 1 + 0.948 946 908;
  • 3) 0.948 946 908 × 2 = 1 + 0.897 893 816;
  • 4) 0.897 893 816 × 2 = 1 + 0.795 787 632;
  • 5) 0.795 787 632 × 2 = 1 + 0.591 575 264;
  • 6) 0.591 575 264 × 2 = 1 + 0.183 150 528;
  • 7) 0.183 150 528 × 2 = 0 + 0.366 301 056;
  • 8) 0.366 301 056 × 2 = 0 + 0.732 602 112;
  • 9) 0.732 602 112 × 2 = 1 + 0.465 204 224;
  • 10) 0.465 204 224 × 2 = 0 + 0.930 408 448;
  • 11) 0.930 408 448 × 2 = 1 + 0.860 816 896;
  • 12) 0.860 816 896 × 2 = 1 + 0.721 633 792;
  • 13) 0.721 633 792 × 2 = 1 + 0.443 267 584;
  • 14) 0.443 267 584 × 2 = 0 + 0.886 535 168;
  • 15) 0.886 535 168 × 2 = 1 + 0.773 070 336;
  • 16) 0.773 070 336 × 2 = 1 + 0.546 140 672;
  • 17) 0.546 140 672 × 2 = 1 + 0.092 281 344;
  • 18) 0.092 281 344 × 2 = 0 + 0.184 562 688;
  • 19) 0.184 562 688 × 2 = 0 + 0.369 125 376;
  • 20) 0.369 125 376 × 2 = 0 + 0.738 250 752;
  • 21) 0.738 250 752 × 2 = 1 + 0.476 501 504;
  • 22) 0.476 501 504 × 2 = 0 + 0.953 003 008;
  • 23) 0.953 003 008 × 2 = 1 + 0.906 006 016;
  • 24) 0.906 006 016 × 2 = 1 + 0.812 012 032;
  • 25) 0.812 012 032 × 2 = 1 + 0.624 024 064;
  • 26) 0.624 024 064 × 2 = 1 + 0.248 048 128;
  • 27) 0.248 048 128 × 2 = 0 + 0.496 096 256;
  • 28) 0.496 096 256 × 2 = 0 + 0.992 192 512;
  • 29) 0.992 192 512 × 2 = 1 + 0.984 385 024;
  • 30) 0.984 385 024 × 2 = 1 + 0.968 770 048;
  • 31) 0.968 770 048 × 2 = 1 + 0.937 540 096;
  • 32) 0.937 540 096 × 2 = 1 + 0.875 080 192;
  • 33) 0.875 080 192 × 2 = 1 + 0.750 160 384;
  • 34) 0.750 160 384 × 2 = 1 + 0.500 320 768;
  • 35) 0.500 320 768 × 2 = 1 + 0.000 641 536;
  • 36) 0.000 641 536 × 2 = 0 + 0.001 283 072;
  • 37) 0.001 283 072 × 2 = 0 + 0.002 566 144;
  • 38) 0.002 566 144 × 2 = 0 + 0.005 132 288;
  • 39) 0.005 132 288 × 2 = 0 + 0.010 264 576;
  • 40) 0.010 264 576 × 2 = 0 + 0.020 529 152;
  • 41) 0.020 529 152 × 2 = 0 + 0.041 058 304;
  • 42) 0.041 058 304 × 2 = 0 + 0.082 116 608;
  • 43) 0.082 116 608 × 2 = 0 + 0.164 233 216;
  • 44) 0.164 233 216 × 2 = 0 + 0.328 466 432;
  • 45) 0.328 466 432 × 2 = 0 + 0.656 932 864;
  • 46) 0.656 932 864 × 2 = 1 + 0.313 865 728;
  • 47) 0.313 865 728 × 2 = 0 + 0.627 731 456;
  • 48) 0.627 731 456 × 2 = 1 + 0.255 462 912;
  • 49) 0.255 462 912 × 2 = 0 + 0.510 925 824;
  • 50) 0.510 925 824 × 2 = 1 + 0.021 851 648;
  • 51) 0.021 851 648 × 2 = 0 + 0.043 703 296;
  • 52) 0.043 703 296 × 2 = 0 + 0.087 406 592;
  • 53) 0.087 406 592 × 2 = 0 + 0.174 813 184;
  • 54) 0.174 813 184 × 2 = 0 + 0.349 626 368;

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:


0.487 236 727(10) =

0.0111 1100 1011 1011 1000 1011 1100 1111 1110 0000 0000 0101 0100 00(2)

5. Positive number before normalization:

0.487 236 727(10) =

0.0111 1100 1011 1011 1000 1011 1100 1111 1110 0000 0000 0101 0100 00(2)

6. Normalize the binary representation of the number.

Shift the decimal mark 2 positions to the right, so that only one non zero digit remains to the left of it:


0.487 236 727(10) =

0.0111 1100 1011 1011 1000 1011 1100 1111 1110 0000 0000 0101 0100 00(2) =

0.0111 1100 1011 1011 1000 1011 1100 1111 1110 0000 0000 0101 0100 00(2) × 20 =

1.1111 0010 1110 1110 0010 1111 0011 1111 1000 0000 0001 0101 0000(2) × 2-2


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): -2

Mantissa (not normalized):
1.1111 0010 1110 1110 0010 1111 0011 1111 1000 0000 0001 0101 0000


8. Adjust the exponent.

Use the 11 bit excess/bias notation:


Exponent (adjusted) =

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

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

(-2 + 1 023)(10) =

1 021(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;
  • 1 021 ÷ 2 = 510 + 1;
  • 510 ÷ 2 = 255 + 0;
  • 255 ÷ 2 = 127 + 1;
  • 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;

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) =

1021(10) =

011 1111 1101(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, only if necessary (not the case here).


Mantissa (normalized) =

1. 1111 0010 1110 1110 0010 1111 0011 1111 1000 0000 0001 0101 0000 =

1111 0010 1110 1110 0010 1111 0011 1111 1000 0000 0001 0101 0000


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) =
011 1111 1101

Mantissa (52 bits) =
1111 0010 1110 1110 0010 1111 0011 1111 1000 0000 0001 0101 0000


Decimal number 0.487 236 727 converted to 64 bit double precision IEEE 754 binary floating point representation:

0 - 011 1111 1101 - 1111 0010 1110 1110 0010 1111 0011 1111 1000 0000 0001 0101 0000

» Convert decimal 0.487 236 736 to 64 bit double precision IEEE 754 binary floating point representation standard

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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