0.000 004 42 Converted to 32 Bit Single Precision IEEE 754 Binary Floating Point Representation Standard

Convert decimal 0.000 004 42(10) to 32 bit single precision IEEE 754 binary floating point representation standard (1 bit for sign, 8 bits for exponent, 23 bits for mantissa)

What are the steps to convert decimal number
0.000 004 42(10) to 32 bit single precision IEEE 754 binary floating point representation (1 bit for sign, 8 bits for exponent, 23 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: 0.000 004 42.

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) 0.000 004 42 × 2 = 0 + 0.000 008 84;
  • 2) 0.000 008 84 × 2 = 0 + 0.000 017 68;
  • 3) 0.000 017 68 × 2 = 0 + 0.000 035 36;
  • 4) 0.000 035 36 × 2 = 0 + 0.000 070 72;
  • 5) 0.000 070 72 × 2 = 0 + 0.000 141 44;
  • 6) 0.000 141 44 × 2 = 0 + 0.000 282 88;
  • 7) 0.000 282 88 × 2 = 0 + 0.000 565 76;
  • 8) 0.000 565 76 × 2 = 0 + 0.001 131 52;
  • 9) 0.001 131 52 × 2 = 0 + 0.002 263 04;
  • 10) 0.002 263 04 × 2 = 0 + 0.004 526 08;
  • 11) 0.004 526 08 × 2 = 0 + 0.009 052 16;
  • 12) 0.009 052 16 × 2 = 0 + 0.018 104 32;
  • 13) 0.018 104 32 × 2 = 0 + 0.036 208 64;
  • 14) 0.036 208 64 × 2 = 0 + 0.072 417 28;
  • 15) 0.072 417 28 × 2 = 0 + 0.144 834 56;
  • 16) 0.144 834 56 × 2 = 0 + 0.289 669 12;
  • 17) 0.289 669 12 × 2 = 0 + 0.579 338 24;
  • 18) 0.579 338 24 × 2 = 1 + 0.158 676 48;
  • 19) 0.158 676 48 × 2 = 0 + 0.317 352 96;
  • 20) 0.317 352 96 × 2 = 0 + 0.634 705 92;
  • 21) 0.634 705 92 × 2 = 1 + 0.269 411 84;
  • 22) 0.269 411 84 × 2 = 0 + 0.538 823 68;
  • 23) 0.538 823 68 × 2 = 1 + 0.077 647 36;
  • 24) 0.077 647 36 × 2 = 0 + 0.155 294 72;
  • 25) 0.155 294 72 × 2 = 0 + 0.310 589 44;
  • 26) 0.310 589 44 × 2 = 0 + 0.621 178 88;
  • 27) 0.621 178 88 × 2 = 1 + 0.242 357 76;
  • 28) 0.242 357 76 × 2 = 0 + 0.484 715 52;
  • 29) 0.484 715 52 × 2 = 0 + 0.969 431 04;
  • 30) 0.969 431 04 × 2 = 1 + 0.938 862 08;
  • 31) 0.938 862 08 × 2 = 1 + 0.877 724 16;
  • 32) 0.877 724 16 × 2 = 1 + 0.755 448 32;
  • 33) 0.755 448 32 × 2 = 1 + 0.510 896 64;
  • 34) 0.510 896 64 × 2 = 1 + 0.021 793 28;
  • 35) 0.021 793 28 × 2 = 0 + 0.043 586 56;
  • 36) 0.043 586 56 × 2 = 0 + 0.087 173 12;
  • 37) 0.087 173 12 × 2 = 0 + 0.174 346 24;
  • 38) 0.174 346 24 × 2 = 0 + 0.348 692 48;
  • 39) 0.348 692 48 × 2 = 0 + 0.697 384 96;
  • 40) 0.697 384 96 × 2 = 1 + 0.394 769 92;
  • 41) 0.394 769 92 × 2 = 0 + 0.789 539 84;

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:


0.000 004 42(10) =


0.0000 0000 0000 0000 0100 1010 0010 0111 1100 0001 0(2)

5. Positive number before normalization:

0.000 004 42(10) =


0.0000 0000 0000 0000 0100 1010 0010 0111 1100 0001 0(2)

6. Normalize the binary representation of the number.

Shift the decimal mark 18 positions to the right, so that only one non zero digit remains to the left of it:


0.000 004 42(10) =


0.0000 0000 0000 0000 0100 1010 0010 0111 1100 0001 0(2) =


0.0000 0000 0000 0000 0100 1010 0010 0111 1100 0001 0(2) × 20 =


1.0010 1000 1001 1111 0000 010(2) × 2-18


7. Up to this moment, there are the following elements that would feed into the 32 bit single precision IEEE 754 binary floating point representation:

Sign 0 (a positive number)


Exponent (unadjusted): -18


Mantissa (not normalized):
1.0010 1000 1001 1111 0000 010


8. Adjust the exponent.

Use the 8 bit excess/bias notation:


Exponent (adjusted) =


Exponent (unadjusted) + 2(8-1) - 1 =


-18 + 2(8-1) - 1 =


(-18 + 127)(10) =


109(10)


9. Convert the adjusted exponent from the decimal (base 10) to 8 bit binary.

Use the same technique of repeatedly dividing by 2:


  • division = quotient + remainder;
  • 109 ÷ 2 = 54 + 1;
  • 54 ÷ 2 = 27 + 0;
  • 27 ÷ 2 = 13 + 1;
  • 13 ÷ 2 = 6 + 1;
  • 6 ÷ 2 = 3 + 0;
  • 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) =


109(10) =


0110 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 23 bits, only if necessary (not the case here).


Mantissa (normalized) =


1. 001 0100 0100 1111 1000 0010 =


001 0100 0100 1111 1000 0010


12. The three elements that make up the number's 32 bit single precision IEEE 754 binary floating point representation:

Sign (1 bit) =
0 (a positive number)


Exponent (8 bits) =
0110 1101


Mantissa (23 bits) =
001 0100 0100 1111 1000 0010


Decimal number 0.000 004 42 converted to 32 bit single precision IEEE 754 binary floating point representation:

0 - 0110 1101 - 001 0100 0100 1111 1000 0010


How to convert decimal numbers from base ten to 32 bit single precision IEEE 754 binary floating point standard

Follow the steps below to convert a base 10 decimal number to 32 bit single 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 base ten 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 of the previous dividing 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 previous multiplying operations, starting from the top of the constructed list 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, by shifting the decimal point (or if you prefer, the decimal mark) "n" positions either to the left or to the right, so that only one non zero digit remains to the left of the decimal point.
  • 7. Adjust the exponent in 8 bit excess/bias notation and then convert it from decimal (base 10) to 8 bit binary, by using the same technique of repeatedly dividing by 2, as shown above:
    Exponent (adjusted) = Exponent (unadjusted) + 2(8-1) - 1
  • 8. Normalize mantissa, remove the leading (leftmost) bit, since it's allways '1' (and the decimal sign if the case) and adjust its length to 23 bits, either by removing the excess bits from the right (losing precision...) or by adding extra '0' bits 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 -25.347 from decimal system (base ten) to 32 bit single precision IEEE 754 binary floating point:

  • 1. Start with the positive version of the number:

    |-25.347| = 25.347

  • 2. First convert the integer part, 25. Divide it repeatedly by 2, keeping track of each remainder, until we get a quotient that is equal to zero:
    • division = quotient + remainder;
    • 25 ÷ 2 = 12 + 1;
    • 12 ÷ 2 = 6 + 0;
    • 6 ÷ 2 = 3 + 0;
    • 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:

    25(10) = 1 1001(2)

  • 4. Then convert the fractional part, 0.347. 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) 0.347 × 2 = 0 + 0.694;
    • 2) 0.694 × 2 = 1 + 0.388;
    • 3) 0.388 × 2 = 0 + 0.776;
    • 4) 0.776 × 2 = 1 + 0.552;
    • 5) 0.552 × 2 = 1 + 0.104;
    • 6) 0.104 × 2 = 0 + 0.208;
    • 7) 0.208 × 2 = 0 + 0.416;
    • 8) 0.416 × 2 = 0 + 0.832;
    • 9) 0.832 × 2 = 1 + 0.664;
    • 10) 0.664 × 2 = 1 + 0.328;
    • 11) 0.328 × 2 = 0 + 0.656;
    • 12) 0.656 × 2 = 1 + 0.312;
    • 13) 0.312 × 2 = 0 + 0.624;
    • 14) 0.624 × 2 = 1 + 0.248;
    • 15) 0.248 × 2 = 0 + 0.496;
    • 16) 0.496 × 2 = 0 + 0.992;
    • 17) 0.992 × 2 = 1 + 0.984;
    • 18) 0.984 × 2 = 1 + 0.968;
    • 19) 0.968 × 2 = 1 + 0.936;
    • 20) 0.936 × 2 = 1 + 0.872;
    • 21) 0.872 × 2 = 1 + 0.744;
    • 22) 0.744 × 2 = 1 + 0.488;
    • 23) 0.488 × 2 = 0 + 0.976;
    • 24) 0.976 × 2 = 1 + 0.952;
    • We didn't get any fractional part that was equal to zero. But we had enough iterations (over Mantissa limit = 23) 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:

    0.347(10) = 0.0101 1000 1101 0100 1111 1101(2)

  • 6. Summarizing - the positive number before normalization:

    25.347(10) = 1 1001.0101 1000 1101 0100 1111 1101(2)

  • 7. Normalize the binary representation of the number, shifting the decimal point 4 positions to the left so that only one non-zero digit stays to the left of the decimal point:

    25.347(10) =
    1 1001.0101 1000 1101 0100 1111 1101(2) =
    1 1001.0101 1000 1101 0100 1111 1101(2) × 20 =
    1.1001 0101 1000 1101 0100 1111 1101(2) × 24

  • 8. Up to this moment, there are the following elements that would feed into the 32 bit single precision IEEE 754 binary floating point:

    Sign: 1 (a negative number)

    Exponent (unadjusted): 4

    Mantissa (not-normalized): 1.1001 0101 1000 1101 0100 1111 1101

  • 9. Adjust the exponent in 8 bit excess/bias notation and then convert it from decimal (base 10) to 8 bit binary (base 2), by using the same technique of repeatedly dividing it by 2, as already demonstrated above:

    Exponent (adjusted) = Exponent (unadjusted) + 2(8-1) - 1 = (4 + 127)(10) = 131(10) =
    1000 0011(2)

  • 10. Normalize the mantissa, remove the leading (leftmost) bit, since it's allways '1' (and the decimal point) and adjust its length to 23 bits, by removing the excess bits from the right (losing precision...):

    Mantissa (not-normalized): 1.1001 0101 1000 1101 0100 1111 1101

    Mantissa (normalized): 100 1010 1100 0110 1010 0111

  • Conclusion:

    Sign (1 bit) = 1 (a negative number)

    Exponent (8 bits) = 1000 0011

    Mantissa (23 bits) = 100 1010 1100 0110 1010 0111

  • Number -25.347, converted from the decimal system (base 10) to 32 bit single precision IEEE 754 binary floating point =
    1 - 1000 0011 - 100 1010 1100 0110 1010 0111