How to Use BITLSHIFT Function in Excel: Bitwise Left Shift Operations

21Jan

How to Use BITLSHIFT Function in Excel: Bitwise Left Shift Operations

Need to multiply binary numbers by shifting bits to the left in Excel? The BITLSHIFT function lets you move the bits of a number to the left by a specified number of positions, which effectively multiplies the number by powers of 2. This guide shows you how, step-by-step.

Table of Contents

1. Understand BITLSHIFT Function Logic

By default, BITLSHIFT shifts all bits in a number to the left and fills empty positions on the right with zeros. So before you use BITLSHIFT, you must:

Understand that it works with positive integers only (0 to 2^53-1)
Know that each left shift position multiplies the number by 2 (shifting left by 1 = multiply by 2, by 2 = multiply by 4, etc.)

2. Step-by-Step: Use BITLSHIFT for Bit Shifting

✅ Step 1: Enter Your Numbers in Excel Cells

Open your Excel spreadsheet
In cell A1, enter the number you want to shift (for example: 5)
In cell B1, enter how many positions to shift left (for example: 2)
Leave cell C1 empty for the BITLSHIFT result

✅ Step 2: Write the BITLSHIFT Formula

Click on cell C1 where you want the result
Type the formula: =BITLSHIFT(A1,B1)
Press Enter
Excel shifts the bits and displays the result (in this case: 20)

Now the formula is complete. BITLSHIFT moved all bits two positions to the left, which multiplied 5 by 4 (2^2) to get 20.

3. Tips for Better BITLSHIFT Operations

Use cell references instead of hard-coded numbers so you can change values without editing the formula
Remember that left shift multiplies by powers of 2—shift by 1 = ×2, shift by 2 = ×4, shift by 3 = ×8
Combine with BITRSHIFT to reverse the operation and divide by powers of 2

4. Bonus: Advanced BITLSHIFT for Calculations and Scaling

Want even more control? You can use BITLSHIFT to efficiently multiply numbers or scale values. Here’s an example:


Example 1: Simple left shift multiplication
Number: 3 (binary: 0011)
Shift by: 3 positions
Formula: =BITLSHIFT(A1, 3)
Result: 24 (3 × 2^3 = 3 × 8 = 24)

Example 2: Scale a value by multiplying by power of 2
Original value: 100
Scale factor needed: 16 (which is 2^4)
Formula: =BITLSHIFT(100, 4)
Result: 1600

Example 3: Progressive scaling with variable shift
Base amount: 10
Levels: 5 (shift left by 5 = multiply by 32)
Formula: =BITLSHIFT(Base, Levels)
Result: 320 (10 × 32)

Example 4: Combine left shift with other operations
Starting value: 7
Shift left by: 2
Then add bonus: 5
Formula: =BITLSHIFT(A1, B1) + C1
Result: 33 (7 × 4 + 5)

This approach lets you efficiently multiply by powers of 2 or scale values without using the multiplication operator.

Troubleshooting BITLSHIFT Functions

Sometimes users say that BITLSHIFT returns unexpected results or errors.

Check if your number is really a positive integer between 0 and 2^53
Make sure your shift amount is a valid positive integer (usually 0 to 53).
Review the binary representation—each position shifted left multiplies by 2, so shifting by 3 should multiply by 8.

Another common issue is that BITLSHIFT returns #NUM! error or values that seem too large.

Make sure both arguments are whole numbers, not decimals (BITLSHIFT doesn’t work with decimals).
Verify that neither number is negative—BITLSHIFT requires non-negative integers.
Check that your result doesn’t exceed 2^53-1—shifting a large number left many times may overflow this limit.

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