2.718 281 828 451 2 Converted to 64 Bit Double Precision IEEE 754 Binary Floating Point Representation Standard

Convert decimal 2.718 281 828 451 2(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
2.718 281 828 451 2(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: 2.
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;
  • 2 ÷ 2 = 1 + 0;
  • 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.

2(10) =


10(2)


3. Convert to binary (base 2) the fractional part: 0.718 281 828 451 2.

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) 0.718 281 828 451 2 × 2 = 1 + 0.436 563 656 902 4;
  • 2) 0.436 563 656 902 4 × 2 = 0 + 0.873 127 313 804 8;
  • 3) 0.873 127 313 804 8 × 2 = 1 + 0.746 254 627 609 6;
  • 4) 0.746 254 627 609 6 × 2 = 1 + 0.492 509 255 219 2;
  • 5) 0.492 509 255 219 2 × 2 = 0 + 0.985 018 510 438 4;
  • 6) 0.985 018 510 438 4 × 2 = 1 + 0.970 037 020 876 8;
  • 7) 0.970 037 020 876 8 × 2 = 1 + 0.940 074 041 753 6;
  • 8) 0.940 074 041 753 6 × 2 = 1 + 0.880 148 083 507 2;
  • 9) 0.880 148 083 507 2 × 2 = 1 + 0.760 296 167 014 4;
  • 10) 0.760 296 167 014 4 × 2 = 1 + 0.520 592 334 028 8;
  • 11) 0.520 592 334 028 8 × 2 = 1 + 0.041 184 668 057 6;
  • 12) 0.041 184 668 057 6 × 2 = 0 + 0.082 369 336 115 2;
  • 13) 0.082 369 336 115 2 × 2 = 0 + 0.164 738 672 230 4;
  • 14) 0.164 738 672 230 4 × 2 = 0 + 0.329 477 344 460 8;
  • 15) 0.329 477 344 460 8 × 2 = 0 + 0.658 954 688 921 6;
  • 16) 0.658 954 688 921 6 × 2 = 1 + 0.317 909 377 843 2;
  • 17) 0.317 909 377 843 2 × 2 = 0 + 0.635 818 755 686 4;
  • 18) 0.635 818 755 686 4 × 2 = 1 + 0.271 637 511 372 8;
  • 19) 0.271 637 511 372 8 × 2 = 0 + 0.543 275 022 745 6;
  • 20) 0.543 275 022 745 6 × 2 = 1 + 0.086 550 045 491 2;
  • 21) 0.086 550 045 491 2 × 2 = 0 + 0.173 100 090 982 4;
  • 22) 0.173 100 090 982 4 × 2 = 0 + 0.346 200 181 964 8;
  • 23) 0.346 200 181 964 8 × 2 = 0 + 0.692 400 363 929 6;
  • 24) 0.692 400 363 929 6 × 2 = 1 + 0.384 800 727 859 2;
  • 25) 0.384 800 727 859 2 × 2 = 0 + 0.769 601 455 718 4;
  • 26) 0.769 601 455 718 4 × 2 = 1 + 0.539 202 911 436 8;
  • 27) 0.539 202 911 436 8 × 2 = 1 + 0.078 405 822 873 6;
  • 28) 0.078 405 822 873 6 × 2 = 0 + 0.156 811 645 747 2;
  • 29) 0.156 811 645 747 2 × 2 = 0 + 0.313 623 291 494 4;
  • 30) 0.313 623 291 494 4 × 2 = 0 + 0.627 246 582 988 8;
  • 31) 0.627 246 582 988 8 × 2 = 1 + 0.254 493 165 977 6;
  • 32) 0.254 493 165 977 6 × 2 = 0 + 0.508 986 331 955 2;
  • 33) 0.508 986 331 955 2 × 2 = 1 + 0.017 972 663 910 4;
  • 34) 0.017 972 663 910 4 × 2 = 0 + 0.035 945 327 820 8;
  • 35) 0.035 945 327 820 8 × 2 = 0 + 0.071 890 655 641 6;
  • 36) 0.071 890 655 641 6 × 2 = 0 + 0.143 781 311 283 2;
  • 37) 0.143 781 311 283 2 × 2 = 0 + 0.287 562 622 566 4;
  • 38) 0.287 562 622 566 4 × 2 = 0 + 0.575 125 245 132 8;
  • 39) 0.575 125 245 132 8 × 2 = 1 + 0.150 250 490 265 6;
  • 40) 0.150 250 490 265 6 × 2 = 0 + 0.300 500 980 531 2;
  • 41) 0.300 500 980 531 2 × 2 = 0 + 0.601 001 961 062 4;
  • 42) 0.601 001 961 062 4 × 2 = 1 + 0.202 003 922 124 8;
  • 43) 0.202 003 922 124 8 × 2 = 0 + 0.404 007 844 249 6;
  • 44) 0.404 007 844 249 6 × 2 = 0 + 0.808 015 688 499 2;
  • 45) 0.808 015 688 499 2 × 2 = 1 + 0.616 031 376 998 4;
  • 46) 0.616 031 376 998 4 × 2 = 1 + 0.232 062 753 996 8;
  • 47) 0.232 062 753 996 8 × 2 = 0 + 0.464 125 507 993 6;
  • 48) 0.464 125 507 993 6 × 2 = 0 + 0.928 251 015 987 2;
  • 49) 0.928 251 015 987 2 × 2 = 1 + 0.856 502 031 974 4;
  • 50) 0.856 502 031 974 4 × 2 = 1 + 0.713 004 063 948 8;
  • 51) 0.713 004 063 948 8 × 2 = 1 + 0.426 008 127 897 6;
  • 52) 0.426 008 127 897 6 × 2 = 0 + 0.852 016 255 795 2;
  • 53) 0.852 016 255 795 2 × 2 = 1 + 0.704 032 511 590 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).


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:


0.718 281 828 451 2(10) =


0.1011 0111 1110 0001 0101 0001 0110 0010 1000 0010 0100 1100 1110 1(2)

5. Positive number before normalization:

2.718 281 828 451 2(10) =


10.1011 0111 1110 0001 0101 0001 0110 0010 1000 0010 0100 1100 1110 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:


2.718 281 828 451 2(10) =


10.1011 0111 1110 0001 0101 0001 0110 0010 1000 0010 0100 1100 1110 1(2) =


10.1011 0111 1110 0001 0101 0001 0110 0010 1000 0010 0100 1100 1110 1(2) × 20 =


1.0101 1011 1111 0000 1010 1000 1011 0001 0100 0001 0010 0110 0111 01(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):
1.0101 1011 1111 0000 1010 1000 1011 0001 0100 0001 0010 0110 0111 01


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. 0101 1011 1111 0000 1010 1000 1011 0001 0100 0001 0010 0110 0111 01 =


0101 1011 1111 0000 1010 1000 1011 0001 0100 0001 0010 0110 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) =
0101 1011 1111 0000 1010 1000 1011 0001 0100 0001 0010 0110 0111


Decimal number 2.718 281 828 451 2 converted to 64 bit double precision IEEE 754 binary floating point representation:

0 - 100 0000 0000 - 0101 1011 1111 0000 1010 1000 1011 0001 0100 0001 0010 0110 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