Convert 1101 1111 1011 1100 0101 0000 0100 0101 0001 0000 1100 0101 1011 1010 1100 0011 Base 2 Signed Binary Number on 64 Bit - To Base 10 Decimal System Integer

How to convert 1101 1111 1011 1100 0101 0000 0100 0101 0001 0000 1100 0101 1011 1010 1100 0011(2), the base 2 signed binary number on 64 bit, to a base 10 decimal system integer

What are the steps to convert the base 2 signed binary number
1101 1111 1011 1100 0101 0000 0100 0101 0001 0000 1100 0101 1011 1010 1100 0011(2) to a base 10 decimal system equivalent integer?

1. Is this a positive or a negative number?

1101 1111 1011 1100 0101 0000 0100 0101 0001 0000 1100 0101 1011 1010 1100 0011 is the binary representation of a negative integer, on 64 bits (8 Bytes).


  • In a signed binary, the first bit (the leftmost) is reserved for the sign, 1 = negative, 0 = positive. This bit does not count when calculating the absolute value.

2. Construct the unsigned binary number.

Exclude the first bit (the leftmost), that is reserved for the sign:


1101 1111 1011 1100 0101 0000 0100 0101 0001 0000 1100 0101 1011 1010 1100 0011 = 101 1111 1011 1100 0101 0000 0100 0101 0001 0000 1100 0101 1011 1010 1100 0011


3. Map the unsigned binary number's digits versus the corresponding powers of 2 that their place value represent:

  • 262

    1
  • 261

    0
  • 260

    1
  • 259

    1
  • 258

    1
  • 257

    1
  • 256

    1
  • 255

    1
  • 254

    0
  • 253

    1
  • 252

    1
  • 251

    1
  • 250

    1
  • 249

    0
  • 248

    0
  • 247

    0
  • 246

    1
  • 245

    0
  • 244

    1
  • 243

    0
  • 242

    0
  • 241

    0
  • 240

    0
  • 239

    0
  • 238

    1
  • 237

    0
  • 236

    0
  • 235

    0
  • 234

    1
  • 233

    0
  • 232

    1
  • 231

    0
  • 230

    0
  • 229

    0
  • 228

    1
  • 227

    0
  • 226

    0
  • 225

    0
  • 224

    0
  • 223

    1
  • 222

    1
  • 221

    0
  • 220

    0
  • 219

    0
  • 218

    1
  • 217

    0
  • 216

    1
  • 215

    1
  • 214

    0
  • 213

    1
  • 212

    1
  • 211

    1
  • 210

    0
  • 29

    1
  • 28

    0
  • 27

    1
  • 26

    1
  • 25

    0
  • 24

    0
  • 23

    0
  • 22

    0
  • 21

    1
  • 20

    1

4. Multiply each bit by its corresponding power of 2 and add all the terms up.

101 1111 1011 1100 0101 0000 0100 0101 0001 0000 1100 0101 1011 1010 1100 0011(2) =


(1 × 262 + 0 × 261 + 1 × 260 + 1 × 259 + 1 × 258 + 1 × 257 + 1 × 256 + 1 × 255 + 0 × 254 + 1 × 253 + 1 × 252 + 1 × 251 + 1 × 250 + 0 × 249 + 0 × 248 + 0 × 247 + 1 × 246 + 0 × 245 + 1 × 244 + 0 × 243 + 0 × 242 + 0 × 241 + 0 × 240 + 0 × 239 + 1 × 238 + 0 × 237 + 0 × 236 + 0 × 235 + 1 × 234 + 0 × 233 + 1 × 232 + 0 × 231 + 0 × 230 + 0 × 229 + 1 × 228 + 0 × 227 + 0 × 226 + 0 × 225 + 0 × 224 + 1 × 223 + 1 × 222 + 0 × 221 + 0 × 220 + 0 × 219 + 1 × 218 + 0 × 217 + 1 × 216 + 1 × 215 + 0 × 214 + 1 × 213 + 1 × 212 + 1 × 211 + 0 × 210 + 1 × 29 + 0 × 28 + 1 × 27 + 1 × 26 + 0 × 25 + 0 × 24 + 0 × 23 + 0 × 22 + 1 × 21 + 1 × 20)(10) =


(4 611 686 018 427 387 904 + 0 + 1 152 921 504 606 846 976 + 576 460 752 303 423 488 + 288 230 376 151 711 744 + 144 115 188 075 855 872 + 72 057 594 037 927 936 + 36 028 797 018 963 968 + 0 + 9 007 199 254 740 992 + 4 503 599 627 370 496 + 2 251 799 813 685 248 + 1 125 899 906 842 624 + 0 + 0 + 0 + 70 368 744 177 664 + 0 + 17 592 186 044 416 + 0 + 0 + 0 + 0 + 0 + 274 877 906 944 + 0 + 0 + 0 + 17 179 869 184 + 0 + 4 294 967 296 + 0 + 0 + 0 + 268 435 456 + 0 + 0 + 0 + 0 + 8 388 608 + 4 194 304 + 0 + 0 + 0 + 262 144 + 0 + 65 536 + 32 768 + 0 + 8 192 + 4 096 + 2 048 + 0 + 512 + 0 + 128 + 64 + 0 + 0 + 0 + 0 + 2 + 1)(10) =


(4 611 686 018 427 387 904 + 1 152 921 504 606 846 976 + 576 460 752 303 423 488 + 288 230 376 151 711 744 + 144 115 188 075 855 872 + 72 057 594 037 927 936 + 36 028 797 018 963 968 + 9 007 199 254 740 992 + 4 503 599 627 370 496 + 2 251 799 813 685 248 + 1 125 899 906 842 624 + 70 368 744 177 664 + 17 592 186 044 416 + 274 877 906 944 + 17 179 869 184 + 4 294 967 296 + 268 435 456 + 8 388 608 + 4 194 304 + 262 144 + 65 536 + 32 768 + 8 192 + 4 096 + 2 048 + 512 + 128 + 64 + 2 + 1)(10) =


6 898 476 986 789 116 611(10)

5. If needed, adjust the sign of the integer number by the first digit (leftmost) of the signed binary:

1101 1111 1011 1100 0101 0000 0100 0101 0001 0000 1100 0101 1011 1010 1100 0011(2) = -6 898 476 986 789 116 611(10)

1101 1111 1011 1100 0101 0000 0100 0101 0001 0000 1100 0101 1011 1010 1100 0011(2), Base 2 signed binary number, converted and written as a base 10 decimal system equivalent integer:
1101 1111 1011 1100 0101 0000 0100 0101 0001 0000 1100 0101 1011 1010 1100 0011(2) = -6 898 476 986 789 116 611(10)

Spaces were used to group digits: for binary, by 4, for decimal, by 3.


How to convert signed binary numbers from binary system to decimal (base ten)

To understand how to convert a signed binary number from binary system to decimal (base ten), the easiest way is to do it through an example - convert the binary number, 1001 1110, to base ten:

  • In a signed binary, the first bit (leftmost) is reserved for the sign, 1 = negative, 0 = positive. This bit does not count when calculating the absolute value (value without sign). The first bit is 1, so our number is negative.
  • Write bellow the binary number in base two, and above each bit that makes up the binary number write the corresponding power of 2 (numeral base) that its place value represents, starting with zero, from the right of the number (rightmost bit), walking to the left of the number and increasing each corresonding power of 2 by exactly one unit, but ignoring the very first bit (the leftmost, the one representing the sign):
  • powers of 2:   6 5 4 3 2 1 0
    digits: 1 0 0 1 1 1 1 0
  • Build the representation of the positive number in base 10, by taking each digit of the binary number, multiplying it by the corresponding power of 2 and then adding all the terms up, but also taking care of the number sign:

    1001 1110 =


    - (0 × 26 + 0 × 25 + 1 × 24 + 1 × 23 + 1 × 22 + 1 × 21 + 0 × 20)(10) =


    - (0 + 0 + 16 + 8 + 4 + 2 + 0)(10) =


    - (16 + 8 + 4 + 2)(10) =


    -30(10)

  • Binary signed number, 1001 1110 = -30(10), signed negative integer in base 10