The BYCOL function transforms how you work with column data in Excel. It lets you process entire columns at once using LAMBDA expressions, making complex calculations faster and more intuitive. This tutorial shows you exactly how to use BYCOL, from basic operations to advanced applications.
Create Your First BYCOL Function
Let’s start with a simple example to understand how BYCOL works.
Step 1: Prepare Your Data Create a sample dataset with sales figures across multiple columns:
Product A |
Product B |
Product C |
---|---|---|
100 |
150 |
200 |
200 |
250 |
300 |
300 |
350 |
400 |
Step 2: Write Basic BYCOL Syntax The basic structure of BYCOL is:
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=BYCOL(array, LAMBDA(column, expression))
Step 3: Calculate Column Totals Let’s sum each product column:
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=BYCOL(A2:C4, LAMBDA(col, SUM(col)))
This returns:
Product A |
Product B |
Product C |
---|---|---|
600 |
750 |
900 |

Calculate Column Averages with BYCOL
Step 1: Apply AVERAGE Function Replace SUM with AVERAGE in your LAMBDA expression:
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=BYCOL(A2:C4, LAMBDA(col, AVERAGE(col)))

Step 2: Format Results Add number formatting to display averages with two decimal places:
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=BYCOL(A2:C4, LAMBDA(col, ROUND(AVERAGE(col),2)))

Process Multiple Columns Simultaneously
Step 1: Compare Values Calculate the percentage of each value against the column total:
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=BYCOL(A2:C4, LAMBDA(col, col/SUM(col)))
Step 2: Create Conditional Calculations Find values above column average:
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=BYCOL(A2:C4, LAMBDA(col, IF(col>AVERAGE(col), “Above”, “Below”)))
Real-World BYCOL Applications
Sales Analysis Example
Sample Dataset:

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Q1 Sales |
Q2 Sales |
Q3 Sales |
Q4 Sales |
---|---|---|---|
1000 |
1200 |
1500 |
1800 |
1200 |
1400 |
1600 |
2000 |
Calculate Quarter-over-Quarter Growth:
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=BYCOL(A2:D3, LAMBDA(col, (INDEX(col, 2) – INDEX(col, 1)) / INDEX(col, 1)))

Customer Rating Analysis
Process satisfaction scores (1-5) across different service aspects:
Step 1: Calculate Average Ratings
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=BYCOL(ratings, LAMBDA(col, AVERAGE(col)))

Step 2: Identify Top-Performing Categories
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=BYCOL(ratings, LAMBDA(col, IF(AVERAGE(col)>=4, “Excellent”, “Needs Improvement”)))

Essential BYCOL Syntax and Parameters
Key components:
- array: The range of data to process
- LAMBDA(column, expression): The function to apply
- column: References each column in the array
- expression: The calculation to perform
Getting More from BYCOL
BYCOL opens new possibilities for column-based calculations in Excel. Start with simple operations, then build more complex expressions as you become comfortable with the syntax.
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