-0.000 007 4 Converted to 32 Bit Single Precision IEEE 754 Binary Floating Point Representation Standard

Convert decimal -0.000 007 4(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
-0.000 007 4(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. Start with the positive version of the number:

|-0.000 007 4| = 0.000 007 4


2. 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;

3. 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)


4. Convert to binary (base 2) the fractional part: 0.000 007 4.

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) 0.000 007 4 × 2 = 0 + 0.000 014 8;
  • 2) 0.000 014 8 × 2 = 0 + 0.000 029 6;
  • 3) 0.000 029 6 × 2 = 0 + 0.000 059 2;
  • 4) 0.000 059 2 × 2 = 0 + 0.000 118 4;
  • 5) 0.000 118 4 × 2 = 0 + 0.000 236 8;
  • 6) 0.000 236 8 × 2 = 0 + 0.000 473 6;
  • 7) 0.000 473 6 × 2 = 0 + 0.000 947 2;
  • 8) 0.000 947 2 × 2 = 0 + 0.001 894 4;
  • 9) 0.001 894 4 × 2 = 0 + 0.003 788 8;
  • 10) 0.003 788 8 × 2 = 0 + 0.007 577 6;
  • 11) 0.007 577 6 × 2 = 0 + 0.015 155 2;
  • 12) 0.015 155 2 × 2 = 0 + 0.030 310 4;
  • 13) 0.030 310 4 × 2 = 0 + 0.060 620 8;
  • 14) 0.060 620 8 × 2 = 0 + 0.121 241 6;
  • 15) 0.121 241 6 × 2 = 0 + 0.242 483 2;
  • 16) 0.242 483 2 × 2 = 0 + 0.484 966 4;
  • 17) 0.484 966 4 × 2 = 0 + 0.969 932 8;
  • 18) 0.969 932 8 × 2 = 1 + 0.939 865 6;
  • 19) 0.939 865 6 × 2 = 1 + 0.879 731 2;
  • 20) 0.879 731 2 × 2 = 1 + 0.759 462 4;
  • 21) 0.759 462 4 × 2 = 1 + 0.518 924 8;
  • 22) 0.518 924 8 × 2 = 1 + 0.037 849 6;
  • 23) 0.037 849 6 × 2 = 0 + 0.075 699 2;
  • 24) 0.075 699 2 × 2 = 0 + 0.151 398 4;
  • 25) 0.151 398 4 × 2 = 0 + 0.302 796 8;
  • 26) 0.302 796 8 × 2 = 0 + 0.605 593 6;
  • 27) 0.605 593 6 × 2 = 1 + 0.211 187 2;
  • 28) 0.211 187 2 × 2 = 0 + 0.422 374 4;
  • 29) 0.422 374 4 × 2 = 0 + 0.844 748 8;
  • 30) 0.844 748 8 × 2 = 1 + 0.689 497 6;
  • 31) 0.689 497 6 × 2 = 1 + 0.378 995 2;
  • 32) 0.378 995 2 × 2 = 0 + 0.757 990 4;
  • 33) 0.757 990 4 × 2 = 1 + 0.515 980 8;
  • 34) 0.515 980 8 × 2 = 1 + 0.031 961 6;
  • 35) 0.031 961 6 × 2 = 0 + 0.063 923 2;
  • 36) 0.063 923 2 × 2 = 0 + 0.127 846 4;
  • 37) 0.127 846 4 × 2 = 0 + 0.255 692 8;
  • 38) 0.255 692 8 × 2 = 0 + 0.511 385 6;
  • 39) 0.511 385 6 × 2 = 1 + 0.022 771 2;
  • 40) 0.022 771 2 × 2 = 0 + 0.045 542 4;
  • 41) 0.045 542 4 × 2 = 0 + 0.091 084 8;

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).


5. 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:


0.000 007 4(10) =


0.0000 0000 0000 0000 0111 1100 0010 0110 1100 0010 0(2)

6. Positive number before normalization:

0.000 007 4(10) =


0.0000 0000 0000 0000 0111 1100 0010 0110 1100 0010 0(2)

7. 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:


0.000 007 4(10) =


0.0000 0000 0000 0000 0111 1100 0010 0110 1100 0010 0(2) =


0.0000 0000 0000 0000 0111 1100 0010 0110 1100 0010 0(2) × 20 =


1.1111 0000 1001 1011 0000 100(2) × 2-18


8. 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 1 (a negative number)


Exponent (unadjusted): -18


Mantissa (not normalized):
1.1111 0000 1001 1011 0000 100


9. 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)


10. 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;

11. 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)


12. 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. 111 1000 0100 1101 1000 0100 =


111 1000 0100 1101 1000 0100


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

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


Exponent (8 bits) =
0110 1101


Mantissa (23 bits) =
111 1000 0100 1101 1000 0100


Decimal number -0.000 007 4 converted to 32 bit single precision IEEE 754 binary floating point representation:

1 - 0110 1101 - 111 1000 0100 1101 1000 0100


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