Excel Formula Calculate Change? Easy % Difference Guide

To calculate change in Excel, use the formula (New Value - Old Value) / Old Value and format the result as a percentage. This works for both percent increase and percent decrease, and it is the standard way to measure change between two numbers in a spreadsheet.

Formula

The percent change formula in Excel is written as:

Percent Change = (New Value – Old Value) / Old Value

In symbols: %Δ = (Vnew – Vold) / Vold

• V_old – the original or baseline value (any real number, but not zero).
• V_new – the later or updated value.
• %Δ – the change expressed as a decimal (multiply by 100 to get percent).

If you want the result to show as a percentage, either multiply by 100 in the formula or format the cell with the Percent number format. The formula itself is the same for increases and decreases – a negative result means a decrease.

Worked Example

Using the default values from the calculator above: old value = 50, new value = 75.

1. Subtract the old value from the new: 75 – 50 = 25.
2. Divide by the old value: 25 ÷ 50 = 0.5.
3. Convert to percent: 0.5 × 100 = 50%.

The result is a 50% increase. The absolute difference is 25. This matches the calculator output above.

When to Use This Formula

Use the percent change formula whenever you need to compare two values over time or between two scenarios. Common examples:

• Month-over-month sales growth.
• Year-over-year revenue change.
• Price increase or discount on a product.
• Change in website traffic or social media followers.
• Grade improvement from one exam to the next.

The formula is most meaningful when the old value is positive and not zero. If the old value is zero, the formula divides by zero and returns #DIV/0! in Excel – there is no mathematically valid percent change from zero.

How to Enter It in Excel

Suppose your old value is in cell A1 and the new value is in cell B1. In cell C1, type:

=(B1-A1)/A1

Then press Enter. To show the result as a percentage:

1. Select cell C1.
2. Go to the Home tab.
3. In the Number group, click the percent symbol (%).

Excel will multiply the decimal by 100 and add the percent sign. If you prefer to keep the formula as a plain number without formatting, you can multiply by 100 explicitly:

=(B1-A1)/A1*100

Common Mistakes and How to Avoid Them

• Dividing by the wrong value. Always divide by the old (baseline) value, not the new one. Dividing by the new value gives a different number that is not the standard percent change.
• Forgetting to format as percent. If you don’t format the cell, you’ll see 0.5 instead of 50%. That’s still correct, but it can confuse readers.
• Mixing up order. The formula is (new – old). If you reverse it, you get the negative of the true change.
• Using zero as the old value. Excel returns #DIV/0! because division by zero is undefined. Use an alternative like an absolute difference or label it as “not applicable.�
• Rounding too early. If you round intermediate steps, the final percent can be off. Let Excel keep full precision, then round the final display.

Limitations and When Not to Use It

The percent change formula is simple and widely used, but it has limits:

• Zero or negative baselines. If the old value is zero, percent change is undefined. If the old value is negative (e.g., a loss), the formula still works arithmetically but the result can be misleading. For example, from -10 to -5 gives +50%, which may not reflect the real-world meaning.
• Small baselines exaggerate. A change from 1 to 2 is a 100% increase, but the absolute difference is just 1. In such cases, consider reporting the absolute difference alongside the percent.
• Not a growth rate over time. The formula measures change between two points, not an annualized rate. For compound growth, use the CAGR formula: (End/Start)^(1/years) - 1.
• Not for comparing percentages themselves. If you are comparing two percentages (e.g., unemployment rate from 5% to 6%), the formula gives the percent change in the rate, not the percentage-point change. The percentage-point change is simply 6 – 5 = 1 percentage point.

Frequently Asked Questions

How do I calculate percent change in Excel for multiple rows?

Enter the formula in the first data row, then drag the fill handle (the small square at the bottom-right of the cell) down to copy it to other rows. Excel will automatically adjust the cell references relative to each row.

What if my old value is zero?

Excel will show a #DIV/0! error because you cannot divide by zero. There is no standard percent change from zero. You can use the absolute difference instead, or write a formula that checks for zero, such as =IF(A1=0, "N/A", (B1-A1)/A1).

How do I show a negative percent change in red?

Use conditional formatting. Select the cells with the percent change, go to Home > Conditional Formatting > Highlight Cells Rules > Less Than, and enter 0. Then choose a red fill.

Is percent change the same as percentage difference?

No. Percent change uses the old value as the denominator. Percentage difference (also called relative percentage difference) uses the average of the two values as the denominator: |new – old| / ((new + old)/2) * 100. Use percent change when comparing over time; use percentage difference when comparing two equally valid measurements.

Can I calculate percent change without a formula?

Yes. You can use Excel’s built-in Percentage Change feature in some chart types, but that is for visualization. For a number, the formula is the simplest and most reliable method.

Does the formula work for decreases?

Yes. If the new value is smaller than the old, the result is negative, which indicates a decrease. For example, from 80 to 60 gives (60-80)/80 = -0.25, or -25%.

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in old | Old Value | - | 50 | 0
in new | New Value | - | 75 | 0
out change | Percent Change | % | (new - old) / old * 100 | 2
out diff | Absolute Difference | - | new - old | 2