Convert the Number -1 302.123 456 789 012 345 67 to 64 Bit Double Precision IEEE 754 Binary Floating Point Representation Standard, From a Base Ten Decimal System Number. Detailed Explanations

Number -1 302.123 456 789 012 345 67(10) converted and written in 64 bit double precision IEEE 754 binary floating point representation (1 bit for sign, 11 bits for exponent, 52 bits for mantissa)

The first steps we'll go through to make the conversion:

Convert to binary (to base 2) the integer part of the number.

Convert to binary the fractional part of the number.


1. Start with the positive version of the number:

|-1 302.123 456 789 012 345 67| = 1 302.123 456 789 012 345 67

2. First, convert to binary (in base 2) the integer part: 1 302.
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;
  • 1 302 ÷ 2 = 651 + 0;
  • 651 ÷ 2 = 325 + 1;
  • 325 ÷ 2 = 162 + 1;
  • 162 ÷ 2 = 81 + 0;
  • 81 ÷ 2 = 40 + 1;
  • 40 ÷ 2 = 20 + 0;
  • 20 ÷ 2 = 10 + 0;
  • 10 ÷ 2 = 5 + 0;
  • 5 ÷ 2 = 2 + 1;
  • 2 ÷ 2 = 1 + 0;
  • 1 ÷ 2 = 0 + 1;

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.


1 302(10) =


101 0001 0110(2)


4. Convert to binary (base 2) the fractional part: 0.123 456 789 012 345 67.

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) 0.123 456 789 012 345 67 × 2 = 0 + 0.246 913 578 024 691 34;
  • 2) 0.246 913 578 024 691 34 × 2 = 0 + 0.493 827 156 049 382 68;
  • 3) 0.493 827 156 049 382 68 × 2 = 0 + 0.987 654 312 098 765 36;
  • 4) 0.987 654 312 098 765 36 × 2 = 1 + 0.975 308 624 197 530 72;
  • 5) 0.975 308 624 197 530 72 × 2 = 1 + 0.950 617 248 395 061 44;
  • 6) 0.950 617 248 395 061 44 × 2 = 1 + 0.901 234 496 790 122 88;
  • 7) 0.901 234 496 790 122 88 × 2 = 1 + 0.802 468 993 580 245 76;
  • 8) 0.802 468 993 580 245 76 × 2 = 1 + 0.604 937 987 160 491 52;
  • 9) 0.604 937 987 160 491 52 × 2 = 1 + 0.209 875 974 320 983 04;
  • 10) 0.209 875 974 320 983 04 × 2 = 0 + 0.419 751 948 641 966 08;
  • 11) 0.419 751 948 641 966 08 × 2 = 0 + 0.839 503 897 283 932 16;
  • 12) 0.839 503 897 283 932 16 × 2 = 1 + 0.679 007 794 567 864 32;
  • 13) 0.679 007 794 567 864 32 × 2 = 1 + 0.358 015 589 135 728 64;
  • 14) 0.358 015 589 135 728 64 × 2 = 0 + 0.716 031 178 271 457 28;
  • 15) 0.716 031 178 271 457 28 × 2 = 1 + 0.432 062 356 542 914 56;
  • 16) 0.432 062 356 542 914 56 × 2 = 0 + 0.864 124 713 085 829 12;
  • 17) 0.864 124 713 085 829 12 × 2 = 1 + 0.728 249 426 171 658 24;
  • 18) 0.728 249 426 171 658 24 × 2 = 1 + 0.456 498 852 343 316 48;
  • 19) 0.456 498 852 343 316 48 × 2 = 0 + 0.912 997 704 686 632 96;
  • 20) 0.912 997 704 686 632 96 × 2 = 1 + 0.825 995 409 373 265 92;
  • 21) 0.825 995 409 373 265 92 × 2 = 1 + 0.651 990 818 746 531 84;
  • 22) 0.651 990 818 746 531 84 × 2 = 1 + 0.303 981 637 493 063 68;
  • 23) 0.303 981 637 493 063 68 × 2 = 0 + 0.607 963 274 986 127 36;
  • 24) 0.607 963 274 986 127 36 × 2 = 1 + 0.215 926 549 972 254 72;
  • 25) 0.215 926 549 972 254 72 × 2 = 0 + 0.431 853 099 944 509 44;
  • 26) 0.431 853 099 944 509 44 × 2 = 0 + 0.863 706 199 889 018 88;
  • 27) 0.863 706 199 889 018 88 × 2 = 1 + 0.727 412 399 778 037 76;
  • 28) 0.727 412 399 778 037 76 × 2 = 1 + 0.454 824 799 556 075 52;
  • 29) 0.454 824 799 556 075 52 × 2 = 0 + 0.909 649 599 112 151 04;
  • 30) 0.909 649 599 112 151 04 × 2 = 1 + 0.819 299 198 224 302 08;
  • 31) 0.819 299 198 224 302 08 × 2 = 1 + 0.638 598 396 448 604 16;
  • 32) 0.638 598 396 448 604 16 × 2 = 1 + 0.277 196 792 897 208 32;
  • 33) 0.277 196 792 897 208 32 × 2 = 0 + 0.554 393 585 794 416 64;
  • 34) 0.554 393 585 794 416 64 × 2 = 1 + 0.108 787 171 588 833 28;
  • 35) 0.108 787 171 588 833 28 × 2 = 0 + 0.217 574 343 177 666 56;
  • 36) 0.217 574 343 177 666 56 × 2 = 0 + 0.435 148 686 355 333 12;
  • 37) 0.435 148 686 355 333 12 × 2 = 0 + 0.870 297 372 710 666 24;
  • 38) 0.870 297 372 710 666 24 × 2 = 1 + 0.740 594 745 421 332 48;
  • 39) 0.740 594 745 421 332 48 × 2 = 1 + 0.481 189 490 842 664 96;
  • 40) 0.481 189 490 842 664 96 × 2 = 0 + 0.962 378 981 685 329 92;
  • 41) 0.962 378 981 685 329 92 × 2 = 1 + 0.924 757 963 370 659 84;
  • 42) 0.924 757 963 370 659 84 × 2 = 1 + 0.849 515 926 741 319 68;
  • 43) 0.849 515 926 741 319 68 × 2 = 1 + 0.699 031 853 482 639 36;
  • 44) 0.699 031 853 482 639 36 × 2 = 1 + 0.398 063 706 965 278 72;
  • 45) 0.398 063 706 965 278 72 × 2 = 0 + 0.796 127 413 930 557 44;
  • 46) 0.796 127 413 930 557 44 × 2 = 1 + 0.592 254 827 861 114 88;
  • 47) 0.592 254 827 861 114 88 × 2 = 1 + 0.184 509 655 722 229 76;
  • 48) 0.184 509 655 722 229 76 × 2 = 0 + 0.369 019 311 444 459 52;
  • 49) 0.369 019 311 444 459 52 × 2 = 0 + 0.738 038 622 888 919 04;
  • 50) 0.738 038 622 888 919 04 × 2 = 1 + 0.476 077 245 777 838 08;
  • 51) 0.476 077 245 777 838 08 × 2 = 0 + 0.952 154 491 555 676 16;
  • 52) 0.952 154 491 555 676 16 × 2 = 1 + 0.904 308 983 111 352 32;
  • 53) 0.904 308 983 111 352 32 × 2 = 1 + 0.808 617 966 222 704 64;

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...)


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:


0.123 456 789 012 345 67(10) =


0.0001 1111 1001 1010 1101 1101 0011 0111 0100 0110 1111 0110 0101 1(2)


6. Positive number before normalization:

1 302.123 456 789 012 345 67(10) =


101 0001 0110.0001 1111 1001 1010 1101 1101 0011 0111 0100 0110 1111 0110 0101 1(2)


The last steps we'll go through to make the conversion:

Normalize the binary representation of the number.

Adjust the exponent.

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

Normalize the mantissa.


7. Normalize the binary representation of the number.

Shift the decimal mark 10 positions to the left, so that only one non zero digit remains to the left of it:


1 302.123 456 789 012 345 67(10) =


101 0001 0110.0001 1111 1001 1010 1101 1101 0011 0111 0100 0110 1111 0110 0101 1(2) =


101 0001 0110.0001 1111 1001 1010 1101 1101 0011 0111 0100 0110 1111 0110 0101 1(2) × 20 =


1.0100 0101 1000 0111 1110 0110 1011 0111 0100 1101 1101 0001 1011 1101 1001 011(2) × 210


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): 10


Mantissa (not normalized):
1.0100 0101 1000 0111 1110 0110 1011 0111 0100 1101 1101 0001 1011 1101 1001 011


9. Adjust the exponent.

Use the 11 bit excess/bias notation:


Exponent (adjusted) =


Exponent (unadjusted) + 2(11-1) - 1 =


10 + 2(11-1) - 1 =


(10 + 1 023)(10) =


1 033(10)


10. 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;
  • 1 033 ÷ 2 = 516 + 1;
  • 516 ÷ 2 = 258 + 0;
  • 258 ÷ 2 = 129 + 0;
  • 129 ÷ 2 = 64 + 1;
  • 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;

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) =


1033(10) =


100 0000 1001(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 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. 0100 0101 1000 0111 1110 0110 1011 0111 0100 1101 1101 0001 1011 110 1100 1011 =


0100 0101 1000 0111 1110 0110 1011 0111 0100 1101 1101 0001 1011


13. The three elements that make up the number's 64 bit double precision IEEE 754 binary floating point representation:

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


Exponent (11 bits) =
100 0000 1001


Mantissa (52 bits) =
0100 0101 1000 0111 1110 0110 1011 0111 0100 1101 1101 0001 1011


The base ten decimal number -1 302.123 456 789 012 345 67 converted and written in 64 bit double precision IEEE 754 binary floating point representation:
1 - 100 0000 1001 - 0100 0101 1000 0111 1110 0110 1011 0111 0100 1101 1101 0001 1011

(64 bits IEEE 754)

Number -1 302.123 456 789 012 345 68 converted from decimal system (base 10) to 64 bit double precision IEEE 754 binary floating point representation = ?

Number -1 302.123 456 789 012 345 66 converted from decimal system (base 10) to 64 bit double precision IEEE 754 binary floating point representation = ?

Convert to 64 bit double precision IEEE 754 binary floating point representation standard

A number in 64 bit double precision IEEE 754 binary floating point standard representation requires three building elements: sign (it takes 1 bit and it's either 0 for positive or 1 for negative numbers), exponent (11 bits), mantissa (52 bits)

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All base ten decimal numbers converted to 64 bit double precision IEEE 754 binary floating point

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:

Example: convert the negative number -31.640 215 from the decimal system (base ten) to 64 bit double precision IEEE 754 binary floating point:

Available Base Conversions Between Decimal and Binary Systems

Conversions Between Decimal System Numbers (Written in Base Ten) and Binary System Numbers (Base Two and Computer Representation):


1. Integer -> Binary

2. Decimal -> Binary

3. Binary -> Integer

4. Binary -> Decimal