3.333 333 333 534 Converted to 64 Bit Double Precision IEEE 754 Binary Floating Point Representation Standard

Convert decimal 3.333 333 333 534(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
3.333 333 333 534(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: 0.333 333 333 534.

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) 0.333 333 333 534 × 2 = 0 + 0.666 666 667 068;
  • 2) 0.666 666 667 068 × 2 = 1 + 0.333 333 334 136;
  • 3) 0.333 333 334 136 × 2 = 0 + 0.666 666 668 272;
  • 4) 0.666 666 668 272 × 2 = 1 + 0.333 333 336 544;
  • 5) 0.333 333 336 544 × 2 = 0 + 0.666 666 673 088;
  • 6) 0.666 666 673 088 × 2 = 1 + 0.333 333 346 176;
  • 7) 0.333 333 346 176 × 2 = 0 + 0.666 666 692 352;
  • 8) 0.666 666 692 352 × 2 = 1 + 0.333 333 384 704;
  • 9) 0.333 333 384 704 × 2 = 0 + 0.666 666 769 408;
  • 10) 0.666 666 769 408 × 2 = 1 + 0.333 333 538 816;
  • 11) 0.333 333 538 816 × 2 = 0 + 0.666 667 077 632;
  • 12) 0.666 667 077 632 × 2 = 1 + 0.333 334 155 264;
  • 13) 0.333 334 155 264 × 2 = 0 + 0.666 668 310 528;
  • 14) 0.666 668 310 528 × 2 = 1 + 0.333 336 621 056;
  • 15) 0.333 336 621 056 × 2 = 0 + 0.666 673 242 112;
  • 16) 0.666 673 242 112 × 2 = 1 + 0.333 346 484 224;
  • 17) 0.333 346 484 224 × 2 = 0 + 0.666 692 968 448;
  • 18) 0.666 692 968 448 × 2 = 1 + 0.333 385 936 896;
  • 19) 0.333 385 936 896 × 2 = 0 + 0.666 771 873 792;
  • 20) 0.666 771 873 792 × 2 = 1 + 0.333 543 747 584;
  • 21) 0.333 543 747 584 × 2 = 0 + 0.667 087 495 168;
  • 22) 0.667 087 495 168 × 2 = 1 + 0.334 174 990 336;
  • 23) 0.334 174 990 336 × 2 = 0 + 0.668 349 980 672;
  • 24) 0.668 349 980 672 × 2 = 1 + 0.336 699 961 344;
  • 25) 0.336 699 961 344 × 2 = 0 + 0.673 399 922 688;
  • 26) 0.673 399 922 688 × 2 = 1 + 0.346 799 845 376;
  • 27) 0.346 799 845 376 × 2 = 0 + 0.693 599 690 752;
  • 28) 0.693 599 690 752 × 2 = 1 + 0.387 199 381 504;
  • 29) 0.387 199 381 504 × 2 = 0 + 0.774 398 763 008;
  • 30) 0.774 398 763 008 × 2 = 1 + 0.548 797 526 016;
  • 31) 0.548 797 526 016 × 2 = 1 + 0.097 595 052 032;
  • 32) 0.097 595 052 032 × 2 = 0 + 0.195 190 104 064;
  • 33) 0.195 190 104 064 × 2 = 0 + 0.390 380 208 128;
  • 34) 0.390 380 208 128 × 2 = 0 + 0.780 760 416 256;
  • 35) 0.780 760 416 256 × 2 = 1 + 0.561 520 832 512;
  • 36) 0.561 520 832 512 × 2 = 1 + 0.123 041 665 024;
  • 37) 0.123 041 665 024 × 2 = 0 + 0.246 083 330 048;
  • 38) 0.246 083 330 048 × 2 = 0 + 0.492 166 660 096;
  • 39) 0.492 166 660 096 × 2 = 0 + 0.984 333 320 192;
  • 40) 0.984 333 320 192 × 2 = 1 + 0.968 666 640 384;
  • 41) 0.968 666 640 384 × 2 = 1 + 0.937 333 280 768;
  • 42) 0.937 333 280 768 × 2 = 1 + 0.874 666 561 536;
  • 43) 0.874 666 561 536 × 2 = 1 + 0.749 333 123 072;
  • 44) 0.749 333 123 072 × 2 = 1 + 0.498 666 246 144;
  • 45) 0.498 666 246 144 × 2 = 0 + 0.997 332 492 288;
  • 46) 0.997 332 492 288 × 2 = 1 + 0.994 664 984 576;
  • 47) 0.994 664 984 576 × 2 = 1 + 0.989 329 969 152;
  • 48) 0.989 329 969 152 × 2 = 1 + 0.978 659 938 304;
  • 49) 0.978 659 938 304 × 2 = 1 + 0.957 319 876 608;
  • 50) 0.957 319 876 608 × 2 = 1 + 0.914 639 753 216;
  • 51) 0.914 639 753 216 × 2 = 1 + 0.829 279 506 432;
  • 52) 0.829 279 506 432 × 2 = 1 + 0.658 559 012 864;
  • 53) 0.658 559 012 864 × 2 = 1 + 0.317 118 025 728;

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:


0.333 333 333 534(10) =


0.0101 0101 0101 0101 0101 0101 0101 0110 0011 0001 1111 0111 1111 1(2)

5. Positive number before normalization:

3.333 333 333 534(10) =


11.0101 0101 0101 0101 0101 0101 0101 0110 0011 0001 1111 0111 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:


3.333 333 333 534(10) =


11.0101 0101 0101 0101 0101 0101 0101 0110 0011 0001 1111 0111 1111 1(2) =


11.0101 0101 0101 0101 0101 0101 0101 0110 0011 0001 1111 0111 1111 1(2) × 20 =


1.1010 1010 1010 1010 1010 1010 1010 1011 0001 1000 1111 1011 1111 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 0001 1000 1111 1011 1111 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 0001 1000 1111 1011 1111 11 =


1010 1010 1010 1010 1010 1010 1010 1011 0001 1000 1111 1011 1111


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 0001 1000 1111 1011 1111


Decimal number 3.333 333 333 534 converted to 64 bit double precision IEEE 754 binary floating point representation:

0 - 100 0000 0000 - 1010 1010 1010 1010 1010 1010 1010 1011 0001 1000 1111 1011 1111


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