3.333 333 333 574 Converted to 64 Bit Double Precision IEEE 754 Binary Floating Point Representation Standard

Convert decimal 3.333 333 333 574(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
3.333 333 333 574(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: 3.
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;
  • 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.

3(10) =


11(2)


3. Convert to binary (base 2) the fractional part: 0.333 333 333 574.

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) 0.333 333 333 574 × 2 = 0 + 0.666 666 667 148;
  • 2) 0.666 666 667 148 × 2 = 1 + 0.333 333 334 296;
  • 3) 0.333 333 334 296 × 2 = 0 + 0.666 666 668 592;
  • 4) 0.666 666 668 592 × 2 = 1 + 0.333 333 337 184;
  • 5) 0.333 333 337 184 × 2 = 0 + 0.666 666 674 368;
  • 6) 0.666 666 674 368 × 2 = 1 + 0.333 333 348 736;
  • 7) 0.333 333 348 736 × 2 = 0 + 0.666 666 697 472;
  • 8) 0.666 666 697 472 × 2 = 1 + 0.333 333 394 944;
  • 9) 0.333 333 394 944 × 2 = 0 + 0.666 666 789 888;
  • 10) 0.666 666 789 888 × 2 = 1 + 0.333 333 579 776;
  • 11) 0.333 333 579 776 × 2 = 0 + 0.666 667 159 552;
  • 12) 0.666 667 159 552 × 2 = 1 + 0.333 334 319 104;
  • 13) 0.333 334 319 104 × 2 = 0 + 0.666 668 638 208;
  • 14) 0.666 668 638 208 × 2 = 1 + 0.333 337 276 416;
  • 15) 0.333 337 276 416 × 2 = 0 + 0.666 674 552 832;
  • 16) 0.666 674 552 832 × 2 = 1 + 0.333 349 105 664;
  • 17) 0.333 349 105 664 × 2 = 0 + 0.666 698 211 328;
  • 18) 0.666 698 211 328 × 2 = 1 + 0.333 396 422 656;
  • 19) 0.333 396 422 656 × 2 = 0 + 0.666 792 845 312;
  • 20) 0.666 792 845 312 × 2 = 1 + 0.333 585 690 624;
  • 21) 0.333 585 690 624 × 2 = 0 + 0.667 171 381 248;
  • 22) 0.667 171 381 248 × 2 = 1 + 0.334 342 762 496;
  • 23) 0.334 342 762 496 × 2 = 0 + 0.668 685 524 992;
  • 24) 0.668 685 524 992 × 2 = 1 + 0.337 371 049 984;
  • 25) 0.337 371 049 984 × 2 = 0 + 0.674 742 099 968;
  • 26) 0.674 742 099 968 × 2 = 1 + 0.349 484 199 936;
  • 27) 0.349 484 199 936 × 2 = 0 + 0.698 968 399 872;
  • 28) 0.698 968 399 872 × 2 = 1 + 0.397 936 799 744;
  • 29) 0.397 936 799 744 × 2 = 0 + 0.795 873 599 488;
  • 30) 0.795 873 599 488 × 2 = 1 + 0.591 747 198 976;
  • 31) 0.591 747 198 976 × 2 = 1 + 0.183 494 397 952;
  • 32) 0.183 494 397 952 × 2 = 0 + 0.366 988 795 904;
  • 33) 0.366 988 795 904 × 2 = 0 + 0.733 977 591 808;
  • 34) 0.733 977 591 808 × 2 = 1 + 0.467 955 183 616;
  • 35) 0.467 955 183 616 × 2 = 0 + 0.935 910 367 232;
  • 36) 0.935 910 367 232 × 2 = 1 + 0.871 820 734 464;
  • 37) 0.871 820 734 464 × 2 = 1 + 0.743 641 468 928;
  • 38) 0.743 641 468 928 × 2 = 1 + 0.487 282 937 856;
  • 39) 0.487 282 937 856 × 2 = 0 + 0.974 565 875 712;
  • 40) 0.974 565 875 712 × 2 = 1 + 0.949 131 751 424;
  • 41) 0.949 131 751 424 × 2 = 1 + 0.898 263 502 848;
  • 42) 0.898 263 502 848 × 2 = 1 + 0.796 527 005 696;
  • 43) 0.796 527 005 696 × 2 = 1 + 0.593 054 011 392;
  • 44) 0.593 054 011 392 × 2 = 1 + 0.186 108 022 784;
  • 45) 0.186 108 022 784 × 2 = 0 + 0.372 216 045 568;
  • 46) 0.372 216 045 568 × 2 = 0 + 0.744 432 091 136;
  • 47) 0.744 432 091 136 × 2 = 1 + 0.488 864 182 272;
  • 48) 0.488 864 182 272 × 2 = 0 + 0.977 728 364 544;
  • 49) 0.977 728 364 544 × 2 = 1 + 0.955 456 729 088;
  • 50) 0.955 456 729 088 × 2 = 1 + 0.910 913 458 176;
  • 51) 0.910 913 458 176 × 2 = 1 + 0.821 826 916 352;
  • 52) 0.821 826 916 352 × 2 = 1 + 0.643 653 832 704;
  • 53) 0.643 653 832 704 × 2 = 1 + 0.287 307 665 408;

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:


0.333 333 333 574(10) =


0.0101 0101 0101 0101 0101 0101 0101 0110 0101 1101 1111 0010 1111 1(2)

5. Positive number before normalization:

3.333 333 333 574(10) =


11.0101 0101 0101 0101 0101 0101 0101 0110 0101 1101 1111 0010 1111 1(2)

6. Normalize the binary representation of the number.

Shift the decimal mark 1 positions to the left, so that only one non zero digit remains to the left of it:


3.333 333 333 574(10) =


11.0101 0101 0101 0101 0101 0101 0101 0110 0101 1101 1111 0010 1111 1(2) =


11.0101 0101 0101 0101 0101 0101 0101 0110 0101 1101 1111 0010 1111 1(2) × 20 =


1.1010 1010 1010 1010 1010 1010 1010 1011 0010 1110 1111 1001 0111 11(2) × 21


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): 1


Mantissa (not normalized):
1.1010 1010 1010 1010 1010 1010 1010 1011 0010 1110 1111 1001 0111 11


8. Adjust the exponent.

Use the 11 bit excess/bias notation:


Exponent (adjusted) =


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


1 + 2(11-1) - 1 =


(1 + 1 023)(10) =


1 024(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;
  • 1 024 ÷ 2 = 512 + 0;
  • 512 ÷ 2 = 256 + 0;
  • 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) =


1024(10) =


100 0000 0000(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. 1010 1010 1010 1010 1010 1010 1010 1011 0010 1110 1111 1001 0111 11 =


1010 1010 1010 1010 1010 1010 1010 1011 0010 1110 1111 1001 0111


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 0000


Mantissa (52 bits) =
1010 1010 1010 1010 1010 1010 1010 1011 0010 1110 1111 1001 0111


Decimal number 3.333 333 333 574 converted to 64 bit double precision IEEE 754 binary floating point representation:

0 - 100 0000 0000 - 1010 1010 1010 1010 1010 1010 1010 1011 0010 1110 1111 1001 0111


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