How to Write Capital and Lowercase Letters in Binary

Step-by-Step Guide

1. 1

   Step 1: Consult an ASCII conversion chart.

   Before you convert a letter into binary, you first need to know its numerical representation in the ASCII (or American Standard Conversion for Information Interchange) chart.
   
   The ASCII assigns numerical representations to a variety of generic symbols, including letters.
   
   These numerical representations start at 0 and end with
   225.
   
   Search for a given letter (let’s say “A”) in the “Character” column, which may be abbreviated to “CHR.” That letter’s numerical representation is listed in the “Decimal Value," or “DEC,” column.
   
   Consulting an ASCII chart is the easiest way to determine a letter’s decimal value.To determine an uppercase letter’s decimal value without an ASCII chart, remember the number
   65.
   
   Write out the entire alphabet in uppercase.
   
   Then assign the number 65 to the letter “A.” From there, assign each subsequent letter with each subsequent number (B = 66, C = 67, etc), ending with Z =
   90.
   
   Now you have the decimal value for each uppercase letter according to the ASCII chart.
2. 2

   Step 2: Grab some paper to prepare a worksheet.

   Create three columns.
   
   Label one “Binary Digits,” label the second “Default Value,” and label the third “Calculated Value.” Since binary numbers include eight digits, create eight rows across all three columns.
   
   Next, in all eight rows, write the multiplication sign in between Column 1 and Column 2, and then do the same with the "equals" sign in between Column 2 and Column 3, so that Column 1 x Column 2 = Column 3 across the board., From top to bottom, list the following numbers under "Default Value:" 128; 64; 32; 16; 8; 4; 2;
   1.
   
   If you read the default values from top to bottom, notice how each number is half that of the preceding value (64 is half of 128; 32 is half of 64; etc).
   
   Also note that, if you add the numbers in Column 2 together, you’ll find they equal 225: the highest decimal value assigned in the ASCII chart., Let’s say you’re converting the letter “A,” whose decimal value is
   65.
   
   Be sure to write “65” all the way down at the bottom, so that each of the eight rows in Column 3 remains empty.
   
   Although Column 3 is blank right now, the values that will appear here momentarily will soon add up
   65.To convert a letter into binary numbers, you’re essentially doing a math equation in reverse.
   
   The decimal value for that letter is the “final” answer,” or your starting point.
   
   From here, you’re going to work backwards to determine that letter’s binary number in Column
   1.
   
   To better understand how to do this, let’s do the opposite and convert the binary number “01011010” into a letter to see how this table works.
   
   From top to bottom, fill in Column 1 with these numbers: 0
   - 1
   - 0
   - 1
   - 1- 0
   - 1
   -
   0.
   
   Now multiply each number in Column 1 with the corresponding number in Column 2: 0 x 128 = 0; 1 x 64 = 1; 0 x 32 = 0; etc.
   
   Write the answer to each in Column 3 and then add them all up: 0 + 64 + 0 + 16 + 8 + 0 + 2 + 0 =
   90.
   
   Consult the ASCII chart, and you’ll find that a decimal value of 90 represents the letter “Z.” Now that you’ve converted a binary number into a letter, working your way backwards through the table to do the opposite should be less daunting.
   
   The fact that binary numbers are always either “1” or “0” makes the math easy.
   
   Each of the calculated values in Column 3 will always be either “0” or one of the default values that you’ve already written down in Column
   2. , Figure out which combination of the default values in Column 2 will add up to your letter's decimal value.
   
   For the letter "A," whose decimal value is 65, look at the numbers you've already written down in Column 2 and see which add up to
   65.
   
   Reading Column 2 from top to bottom, you’ll find the second number down is “64,” and the eighth number is “1.” Add these together and you have
   65., Write in “0” for the other rows.
   
   So, for the letter “A,” Column 3 should read from top to bottom: 0
   - 64
   - 0
   - 0
   - 0
   - 0
   - 0
   -
   1., Using either “1” or “0,” enter the appropriate binary digit for each row.
   
   Remember:
   Column 1 x Column 2 = Column
   3.
   
   If Column 3 is 0, enter “0” in Column
   1.
   
   If Column 3 is the same number as Column 2, enter “1.” For instance, with the letter “A:” 0 x 128 = 0; 1 x 64 = 64, 0 x 32 = 0; etc.
   
   When read from top to bottom, Column 1 will now give you the binary number for that letter, so the binary number for “A” is 0
   - 1
   - 0
   - 0
   - 0
   - 0
   - 0
   -
   1.
3. 3

   Step 3: Fill in Column 2.

4. 4

   Step 4: Write your letter’s decimal value below Column 3.

5. 5

   Step 5: Do the math in Column 2.

6. 6

   Step 6: Copy those numbers into Column 3.

7. 7

   Step 7: Fill in Column 1.

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