How to calculate year-over-year growth
Year-over-year (YoY) growth compares a value to the same period a year earlier, as a percentage: YoY % = (current − previous) ÷ previous × 100. Revenue rising from $100,000 to $125,000 is (125,000 − 100,000) ÷ 100,000 = +25%. A negative result means a year-over-year decline.
How to use this calculator
Enter the previous value (a year ago) and the current value. The result shows the percentage change and the absolute difference. It works for revenue, users, traffic, sales, or any metric you track over time. For any two numbers that are not a year apart, use the percentage change calculator.
Why year-over-year is the standard
Comparing to a year ago cancels out seasonality — December sales versus the prior December, not versus November. That makes YoY more meaningful than month-over-month for businesses with seasonal swings, and it's the comparison investors and analysts expect. Growth in revenue only helps if it converts, which the ROI calculator checks.
Reading common YoY changes
From a $100,000 base:
| Current | Change | YoY |
|---|---|---|
| $90,000 | −$10,000 | −10% |
| $110,000 | +$10,000 | +10% |
| $125,000 | +$25,000 | +25% |
| $200,000 | +$100,000 | +100% |
YoY vs. multi-year growth
YoY measures a single year's change. To compare growth across several years as one smoothed annual rate, use CAGR instead — see the CAGR calculator. To judge how efficiently ad spend drove a change, the ROAS calculator helps. This tool is for general information only.
Frequently asked questions
- How do I calculate year-over-year growth?
- Subtract the previous value from the current value, divide by the previous value, then multiply by 100. ($125,000 − $100,000) ÷ $100,000 = +25%.
- What does a negative YoY mean?
- It means the current value is lower than a year ago — a year-over-year decline. For example, $90,000 versus $100,000 is −10%.
- Why use year-over-year instead of month-over-month?
- YoY cancels out seasonal patterns by comparing the same period across years, giving a clearer picture for seasonal businesses.
- What is the difference between YoY and CAGR?
- YoY is the change over a single year. CAGR is the smoothed average annual rate over multiple years, accounting for compounding.
- Can I use YoY for any metric?
- Yes — revenue, users, traffic, units sold, or any figure tracked over time, as long as you compare the same period one year apart.