YOY meaning: YOY (also written YoY) stands for “year over year.” It compares a result, such as sales, sign-ups or costs, with the same period one year earlier. For example, “Q2 revenue grew 12% YOY” means Q2 this year was 12% higher than Q2 last year.
What does YOY mean at work?
YOY is a way to measure change fairly. Many businesses are seasonal. A store sells more in December than in February, so comparing December with the month before can be misleading. Comparing this December with last December removes that seasonal effect.
You’ll see YOY in finance reports, sales dashboards, marketing updates and earnings releases. It can apply to any period: a month, a quarter or a full year.
How to calculate YOY growth
YOY growth (%) = (This period − Same period last year) ÷ Same period last year × 100
Example: a company had $250,000 in Q3 revenue last year and $290,000 in Q3 this year.
- Change: $290,000 − $250,000 = $40,000
- $40,000 ÷ $250,000 = 0.16
- YOY growth = 16%
If the result is negative, it’s a YOY decline. For example, going from 1,000 to 900 customers is a 10% YOY decrease.
Examples of YOY in emails and messages
Leadership update: “October sign-ups are up 22% YOY, our best October yet.”
Slack: “Can you add a YOY column to the dashboard so we can see seasonality?”
Finance email: “Travel costs fell 8% YoY after the new policy.”
Board slide: “Revenue: $4.1M (+11% YOY)”
YOY vs MOM vs YTD
| Term | Stands for | Compares |
|---|---|---|
| YOY | Year over year | This period vs the same period last year |
| MOM | Month over month | This month vs last month |
| QOQ | Quarter over quarter | This quarter vs last quarter |
| YTD | Year to date | A running total since the start of the year (not a comparison) |
You can combine them: “YTD revenue is up 9% YOY” compares this year’s running total with the same point last year. See also QTD.
How to use YOY correctly
- Name the period. “Q3 revenue up 16% YOY” is clear; “up 16% YOY” alone isn’t.
- Show both numbers when it matters. Percentages hide scale: 100% growth from 2 to 4 customers is small.
- Watch for one-off events. A big event last year can distort comparisons.
- Use consistent definitions. Compare the same metric calculated the same way.
- Write it out for outside readers the first time: “year over year (YOY).”
Worked example: YOY growth for a small business
Here’s how a team might report YOY figures for one quarter. The numbers are made up for illustration.
| Metric | Q2 last year | Q2 this year | YOY change |
|---|---|---|---|
| Revenue | $400,000 | $460,000 | +15% |
| New customers | 250 | 230 | −8% |
| Support tickets | 1,200 | 900 | −25% |
Each change uses the same formula: (this year − last year) ÷ last year × 100. Revenue: (460,000 − 400,000) ÷ 400,000 × 100 = 15%. Notice that a negative YOY number isn’t always bad. Fewer support tickets can be good news.
Common YOY mistakes to avoid
- Comparing different lengths of time. A month with five weekends can look weaker than the same month last year with four. Note calendar differences when they matter.
- Ignoring moving holidays. Holidays like Easter or Thanksgiving shopping days can fall in different weeks or months each year and skew results.
- Using an unusual base year. If last year had a one-time spike or a shutdown, YOY growth can look huge or tiny for reasons that have nothing to do with performance.
- Mixing up percentage change and percentage points. If a margin went from 20% to 25%, that’s up 5 percentage points, or 25% YOY.
- Hiding the raw numbers. “Up 200% YOY” sounds great until people learn it went from 1 to 3 sales. Show the actual figures too.
How should you show YOY in a report?
Put the current number first, then the YOY change, and add a short reason when the change is large: “Revenue: $460K (+15% YOY), driven by the new enterprise plan.” In charts, place this year and last year side by side for the same months, so the comparison is easy to see at a glance.
YOY vs QOQ: when should you use each?
QOQ (quarter over quarter) compares one quarter with the one right before it. It shows short-term momentum. YOY compares the same period across years, so it removes seasonal swings. A retailer’s Q1 almost always looks weak next to the holiday-heavy Q4, so QOQ can be misleading. YOY compares Q1 with last year’s Q1 instead, which is a fairer test of real growth.
Where will you see YOY at work?
YOY shows up anywhere results are reported over time: earnings releases, sales dashboards, marketing reports, HR headcount updates and budget reviews. A finance team might say “operating costs are flat YOY,” while a recruiter might report “applications are up 20% YOY.” If you’re new to a role, ask which YOY figures your manager watches most closely.
Related terms
Browse more short forms in our Workplace Acronyms hub.
FAQ
What does YOY stand for?
YOY stands for year over year. It compares a result with the same period one year earlier.
How do you calculate YOY growth?
Subtract last year’s number from this year’s, divide by last year’s number and multiply by 100 to get a percentage.
Is it YOY or YoY?
Both are common and mean the same thing. Pick one style and use it consistently in your documents.
Why use YOY instead of month over month?
YOY removes seasonal swings by comparing the same time of year, which gives a fairer view of real growth.
