Year over Year Growth Calculator

What is year-over-year growth?

Year-over-year (YoY) growth measures how a metric changed compared to the same period in the prior year. It’s the most common way businesses track long-term performance because it filters out seasonal variation.

The formula: subtract last year’s value from this year’s, divide by last year’s value, multiply by 100. If your revenue was $500,000 last year and $650,000 this year, your YoY growth rate is 30%.

YoY growth is useful for any metric that has seasonal patterns. Retail revenue spikes every December. Comparing December to November (month-over-month) shows massive growth followed by a crash. Comparing December 2024 to December 2023 gives a cleaner signal.

How this calculator works

The quick calculator at the top handles the simple case: two values, one percentage. Enter last year’s number and this year’s number.

The multi-year analyzer does more. Enter 2-10 years of data, and it calculates your Compound Annual Growth Rate (CAGR), detects growth patterns, generates a narrative summary you can paste into reports, and charts the trend with a regression line.

The growth pattern detector classifies your data as accelerating, decelerating, steady, volatile, recovery, or plateau. This gives you language for how to describe the trend, not just the numbers.

The projection section estimates where your metric is heading based on your historical CAGR. The cone-shaped range widens for more volatile data because the prediction becomes less certain. It’s a rough guide, not a forecast.

CAGR vs simple YoY growth

Simple YoY growth shows what happened in one specific year. CAGR smooths out the bumps across multiple years into a single annualized rate.

Use simple YoY when you want to analyze a specific period. Use CAGR when you need one number to describe a multi-year trend, like “we grew at 18% annually over five years.”

The CAGR formula: (Ending Value / Starting Value) ^ (1 / Number of Years) - 1.

CAGR and simple average of YoY rates often produce different numbers. CAGR accounts for compounding, which means a 50% gain followed by a 50% loss doesn’t equal zero. CAGR captures this; a simple average doesn’t.

When to use YoY vs other time periods

Use YoY for anything with seasonal patterns or when reporting to leadership. Quarterly and annual business reviews almost always use year-over-year comparisons.

Use month-over-month growth when tracking fast-moving metrics at startups or during campaigns. Use week-over-week growth for short-term experiments and product launches.

A common mistake is comparing just two years and drawing conclusions. Two data points give you a growth rate, but they don’t tell you whether the trend is real or just noise. The multi-year analyzer above helps by showing you the pattern across the full range.

Common pitfalls

Small base numbers inflate percentages. Going from 10 to 20 users is 100% growth, but it doesn’t mean the same thing as going from 10,000 to 20,000. Always report the absolute numbers alongside the percentage.

Negative starting values break the formula. If you lost $100K last year and made $50K this year, the standard formula produces a meaningless result. Report absolute change instead.