Percentage Growth Calculator

Percentage growth: the simplest way to describe change

Percentage growth turns a raw change into a relative comparison. Saying “we gained 50” is incomplete without context: 50 is huge if you started at 10, and modest if you started at 10,000. A percentage answers “how big is the change compared to where we began?”

That idea is used everywhere: business revenue, user counts, weight change, price movement, traffic analytics, savings goals, project budgets, and even personal habits. This calculator helps you compute growth between two values, compare multi-year performance using CAGR, and explore “what-if” forecasts using either simple or compound growth.

The core percentage growth formula

The basic growth rate uses the starting value as the baseline:

The numerator (end − start) is the absolute change. Dividing by the start value converts it into a relative measure. A positive result means growth. A negative result means decline.

Growth percent, change amount, and multiplier

Growth is easier to interpret when you also see the change amount and the multiplier:

• Change amount tells you the raw difference (end − start).
• Multiplier tells you the factor (end ÷ start). A multiplier of 1.35 means “35% growth.”
• Growth percent is (multiplier − 1) × 100.

These three perspectives are the same story in different formats. In reporting, the multiplier can be more intuitive for “x-times” comparisons, while percent is more familiar for headlines and summaries.

When percent growth is undefined

Percent growth requires dividing by the starting value. If the starting value is zero, the result is undefined because division by zero has no meaningful percent interpretation. In that case, you can:

• Use absolute change instead of percent,
• Choose a different baseline (for example, a non-zero reference value), or
• Use a symmetric comparison like percentage difference if you’re comparing two values without a true “start.”

Why a drop then a rise doesn’t “cancel out”

Percent changes compound on the current base. If something drops by 50%, it becomes half its original value. A 50% increase after that is 50% of the smaller number, so it does not return to the starting point. Example:

• Start 100 → drop 50% → 50
• 50 → rise 50% → 75

This is one reason it helps to think in multipliers: a 50% drop is ×0.5, then a 50% rise is ×1.5. The combined effect is ×0.5 × 1.5 = ×0.75 (a net 25% drop).

Average growth rate vs CAGR

People use “average growth rate” in different ways. Sometimes they mean the arithmetic average of period-by-period growth rates. Other times they mean a single smooth rate that would produce the same start and end values. That smooth, compounded rate is CAGR (compound annual growth rate), and it’s usually the most useful one-number summary for multi-year change.

What CAGR means

CAGR answers: “If growth happened at a steady rate each year, what would that rate be to go from start to end over N years?”

CAGR is a geometric concept. It respects compounding, which is why it’s commonly used for investments, business metrics, and long-term comparisons.

When arithmetic average can mislead

If a metric grows 50% one year and falls 50% the next, the arithmetic average growth rate is 0%. But the metric is not back to where it started (100 → 150 → 75). CAGR reflects that because it’s based on start and end values, not the simple average of rates.

Forecasting with a growth rate

Forecasting means extending a growth pattern forward. Two common models are supported here:

Compound growth (exponential)

Compound growth applies the rate to the new value each period, which makes the total curve exponential:

This matches contexts where growth builds on itself: reinvested returns, subscriber growth, population growth, or repeated percentage gains.

Simple growth (linear)

Simple growth adds the same fraction of the starting value each period:

This can be useful for rough planning when the “growth” is more like a fixed increase based on an initial base, or when you explicitly do not want compounding to dominate the estimate.

Reverse growth calculations

Real questions often start from the other side: “If I need to reach 2,000 in five periods at 10% growth, where do I need to start?” Or: “If I started at 1,000 and ended at 2,000 in five periods, what constant growth rate does that imply?”

The Reverse tab solves three practical problems:

• Starting value given end, rate, and periods.
• Ending value given start, rate, and periods.
• Rate given start, end, and periods (compound or simple).

Interpreting growth responsibly

Percent growth is powerful, but it can be misread. A small baseline can create huge percentages that sound dramatic. Meanwhile, large baselines can hide meaningful absolute changes behind small percentages. When you communicate results:

• Share both percent and absolute change when possible.
• Use CAGR for multi-year summaries rather than cherry-picking one year.
• Remember forecasts assume a steady rate, which rarely holds perfectly in real life.

Common use cases

Sales or revenue growth

Use Growth % to compare two months or two quarters, and use CAGR to summarize multi-year performance with a single comparable rate.

Audience and traffic metrics

Growth rates can swing when your starting number is small. The tool’s multiplier and absolute change outputs help keep the story balanced.

Personal goals

If you’re growing savings, training volume, or reading time, the forecast tab can help you plan scenarios. Treat it as a target model, not a promise.

Quick formulas you can reuse

• Growth %: ((end − start) ÷ start) × 100
• Multiplier: end ÷ start
• CAGR: (end/start)^(1/N) − 1
• Compound forecast: start × (1 + r)^N
• Simple forecast: start × (1 + r×N)