2.718 281 827 7 Converted to 64 Bit Double Precision IEEE 754 Binary Floating Point Representation Standard

Convert decimal 2.718 281 827 7(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
2.718 281 827 7(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: 0.718 281 827 7.

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) 0.718 281 827 7 × 2 = 1 + 0.436 563 655 4;
  • 2) 0.436 563 655 4 × 2 = 0 + 0.873 127 310 8;
  • 3) 0.873 127 310 8 × 2 = 1 + 0.746 254 621 6;
  • 4) 0.746 254 621 6 × 2 = 1 + 0.492 509 243 2;
  • 5) 0.492 509 243 2 × 2 = 0 + 0.985 018 486 4;
  • 6) 0.985 018 486 4 × 2 = 1 + 0.970 036 972 8;
  • 7) 0.970 036 972 8 × 2 = 1 + 0.940 073 945 6;
  • 8) 0.940 073 945 6 × 2 = 1 + 0.880 147 891 2;
  • 9) 0.880 147 891 2 × 2 = 1 + 0.760 295 782 4;
  • 10) 0.760 295 782 4 × 2 = 1 + 0.520 591 564 8;
  • 11) 0.520 591 564 8 × 2 = 1 + 0.041 183 129 6;
  • 12) 0.041 183 129 6 × 2 = 0 + 0.082 366 259 2;
  • 13) 0.082 366 259 2 × 2 = 0 + 0.164 732 518 4;
  • 14) 0.164 732 518 4 × 2 = 0 + 0.329 465 036 8;
  • 15) 0.329 465 036 8 × 2 = 0 + 0.658 930 073 6;
  • 16) 0.658 930 073 6 × 2 = 1 + 0.317 860 147 2;
  • 17) 0.317 860 147 2 × 2 = 0 + 0.635 720 294 4;
  • 18) 0.635 720 294 4 × 2 = 1 + 0.271 440 588 8;
  • 19) 0.271 440 588 8 × 2 = 0 + 0.542 881 177 6;
  • 20) 0.542 881 177 6 × 2 = 1 + 0.085 762 355 2;
  • 21) 0.085 762 355 2 × 2 = 0 + 0.171 524 710 4;
  • 22) 0.171 524 710 4 × 2 = 0 + 0.343 049 420 8;
  • 23) 0.343 049 420 8 × 2 = 0 + 0.686 098 841 6;
  • 24) 0.686 098 841 6 × 2 = 1 + 0.372 197 683 2;
  • 25) 0.372 197 683 2 × 2 = 0 + 0.744 395 366 4;
  • 26) 0.744 395 366 4 × 2 = 1 + 0.488 790 732 8;
  • 27) 0.488 790 732 8 × 2 = 0 + 0.977 581 465 6;
  • 28) 0.977 581 465 6 × 2 = 1 + 0.955 162 931 2;
  • 29) 0.955 162 931 2 × 2 = 1 + 0.910 325 862 4;
  • 30) 0.910 325 862 4 × 2 = 1 + 0.820 651 724 8;
  • 31) 0.820 651 724 8 × 2 = 1 + 0.641 303 449 6;
  • 32) 0.641 303 449 6 × 2 = 1 + 0.282 606 899 2;
  • 33) 0.282 606 899 2 × 2 = 0 + 0.565 213 798 4;
  • 34) 0.565 213 798 4 × 2 = 1 + 0.130 427 596 8;
  • 35) 0.130 427 596 8 × 2 = 0 + 0.260 855 193 6;
  • 36) 0.260 855 193 6 × 2 = 0 + 0.521 710 387 2;
  • 37) 0.521 710 387 2 × 2 = 1 + 0.043 420 774 4;
  • 38) 0.043 420 774 4 × 2 = 0 + 0.086 841 548 8;
  • 39) 0.086 841 548 8 × 2 = 0 + 0.173 683 097 6;
  • 40) 0.173 683 097 6 × 2 = 0 + 0.347 366 195 2;
  • 41) 0.347 366 195 2 × 2 = 0 + 0.694 732 390 4;
  • 42) 0.694 732 390 4 × 2 = 1 + 0.389 464 780 8;
  • 43) 0.389 464 780 8 × 2 = 0 + 0.778 929 561 6;
  • 44) 0.778 929 561 6 × 2 = 1 + 0.557 859 123 2;
  • 45) 0.557 859 123 2 × 2 = 1 + 0.115 718 246 4;
  • 46) 0.115 718 246 4 × 2 = 0 + 0.231 436 492 8;
  • 47) 0.231 436 492 8 × 2 = 0 + 0.462 872 985 6;
  • 48) 0.462 872 985 6 × 2 = 0 + 0.925 745 971 2;
  • 49) 0.925 745 971 2 × 2 = 1 + 0.851 491 942 4;
  • 50) 0.851 491 942 4 × 2 = 1 + 0.702 983 884 8;
  • 51) 0.702 983 884 8 × 2 = 1 + 0.405 967 769 6;
  • 52) 0.405 967 769 6 × 2 = 0 + 0.811 935 539 2;
  • 53) 0.811 935 539 2 × 2 = 1 + 0.623 871 078 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:


0.718 281 827 7(10) =


0.1011 0111 1110 0001 0101 0001 0101 1111 0100 1000 0101 1000 1110 1(2)

5. Positive number before normalization:

2.718 281 827 7(10) =


10.1011 0111 1110 0001 0101 0001 0101 1111 0100 1000 0101 1000 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:


2.718 281 827 7(10) =


10.1011 0111 1110 0001 0101 0001 0101 1111 0100 1000 0101 1000 1110 1(2) =


10.1011 0111 1110 0001 0101 0001 0101 1111 0100 1000 0101 1000 1110 1(2) × 20 =


1.0101 1011 1111 0000 1010 1000 1010 1111 1010 0100 0010 1100 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 1010 1111 1010 0100 0010 1100 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 1010 1111 1010 0100 0010 1100 0111 01 =


0101 1011 1111 0000 1010 1000 1010 1111 1010 0100 0010 1100 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 1010 1111 1010 0100 0010 1100 0111


Decimal number 2.718 281 827 7 converted to 64 bit double precision IEEE 754 binary floating point representation:

0 - 100 0000 0000 - 0101 1011 1111 0000 1010 1000 1010 1111 1010 0100 0010 1100 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