Calculating projected growth means picking the right formula for your situation, plugging in your numbers, and adjusting for real-world factors like inflation or market conditions. The approach differs depending on whether you’re projecting investment returns, business revenue, or population and sales trends, but a handful of core methods cover nearly every scenario.
The Two Core Growth Models
Most growth projections rely on one of two patterns: linear (straight-line) growth or compound (exponential) growth. Understanding which one fits your situation is the first decision you need to make.
Linear growth assumes a fixed amount is added each period. If your business added $50,000 in revenue last year, linear projection assumes it will add another $50,000 next year, and $50,000 the year after that. The formula is simple: Future Value = Current Value + (Growth Amount × Number of Periods). This works best for short-term projections where growth is steady and predictable.
Compound growth assumes a fixed percentage increase each period, meaning the actual dollar amount grows over time because each year’s gain builds on the previous year’s total. This is how investments, populations, and most business revenues actually behave over longer timeframes. A $100,000 investment growing at 8% annually doesn’t add $8,000 every year. It adds $8,000 the first year, then $8,640 the next (8% of $108,000), and so on.
How to Calculate Compound Annual Growth Rate
The Compound Annual Growth Rate, or CAGR, is the most widely used formula for measuring and projecting growth. It tells you the smooth annualized rate of return over a period, even if actual year-to-year performance was uneven. The formula:
CAGR = (Ending Value / Beginning Value)^(1 / Number of Years) − 1
Here’s a concrete example. Say your business earned $200,000 in revenue three years ago and $310,000 this year. Divide 310,000 by 200,000 to get 1.55. Raise 1.55 to the power of 1/3 (since three years passed), which gives you roughly 1.157. Subtract 1 and you get 0.157, or 15.7% annual growth.
To project forward using that rate, flip the formula around: Future Value = Current Value × (1 + Growth Rate)^Number of Years. If you expect that same 15.7% rate to continue for two more years, your projected revenue would be $310,000 × (1.157)^2 = roughly $415,000.
CAGR is useful because it smooths out volatility. A business that grew 30% one year and 2% the next looks erratic on a yearly basis, but CAGR gives you a single rate that captures the overall trajectory. The tradeoff is that it hides that volatility entirely, so use it for planning ranges rather than precise predictions.
Projecting Business Revenue Growth
For business forecasting, pure formula-based projection is just the starting point. You’ll typically choose between two broader approaches.
Top-Down Forecasting
Start with the total market size for your industry, then narrow down to what your business can realistically capture. You estimate the overall market, identify your addressable share based on competition and positioning, and multiply by your average revenue per sale. For instance, if your market is worth $50 million and you believe you can capture 3% of it, your revenue projection is $1.5 million.
This approach works well when you’re entering a new market or launching a new product where you don’t have historical sales data to extrapolate from. The risk is that market share assumptions can be wildly optimistic without solid evidence behind them.
Bottom-Up Forecasting
Start with your own operational data: current sales volume, production capacity, marketing spend, staffing levels, and cost of goods sold. You build the projection from your actual ability to produce and sell, factoring in planned hires, new marketing campaigns, or expanded capacity. If you currently sell 500 units a month and plan to add a second sales rep who you expect will generate 150 additional units, your projection builds from those concrete inputs.
Bottom-up forecasting tends to produce more conservative, realistic numbers because it’s grounded in what your business can actually do. It’s the better choice when you have at least a year of operating history.
Many businesses run both methods and compare the results. If top-down says you should hit $2 million but bottom-up says your capacity maxes out at $1.2 million, that gap tells you something important about where you need to invest.
Adjusting for Inflation and Taxes
A raw growth projection can look misleading if you ignore inflation. An investment that grows at 7% annually sounds great, but if inflation runs at 3%, your real purchasing power only increases by about 4% per year. When projecting long-term investment returns, subtract the expected inflation rate from your growth rate to see growth in “today’s dollars.”
For investment projections specifically, you also want to separate pre-tax and after-tax returns. If you expect an 8% annual return but pay taxes on the gains, your effective growth rate will be lower. The exact impact depends on whether gains are taxed annually (as with interest or dividends) or deferred until withdrawal (as with retirement accounts). A tax-deferred account compounds faster because the full amount keeps working for you each year.
If you’re projecting business revenue, inflation affects both sides: your prices may rise, but so do your costs. The simplest approach is to build your projection in constant dollars (ignoring inflation) and note that assumption clearly.
Using Spreadsheets to Automate Projections
Excel and Google Sheets have built-in functions that handle growth calculations without requiring you to build formulas from scratch.
The GROWTH function fits an exponential curve to your historical data and projects future values. Its syntax is GROWTH(known_y_values, known_x_values, new_x_values, constant). The “known_y_values” are your historical data points (revenue, users, sales), the “known_x_values” are the corresponding time periods, and “new_x_values” are the future periods you want to project into. If you have quarterly revenue for the past three years in cells B2 through B13 and time periods 1 through 12 in A2 through A13, entering GROWTH(B2:B13, A2:A13, {13,14,15,16}) will project the next four quarters based on the exponential trend in your data.
The TREND function works similarly but fits a straight line instead of an exponential curve, making it the right choice when your growth pattern is linear rather than compounding.
For a quick visual check, you can also add a trendline to any chart in Excel. Right-click a data series, select “Add Trendline,” and choose between linear, exponential, or polynomial fits. Check “Display equation on chart” to see the formula the software is using, which you can then apply to future periods.
Industry Growth Benchmarks
Your projection is only as good as the growth rate assumption behind it. Using industry benchmarks as a reality check helps ensure your numbers aren’t unreasonably optimistic or conservative. Data compiled by NYU Stern’s Aswath Damodaran, updated as of January 2026, shows how widely growth rates vary across sectors.
Software companies have seen some of the fastest revenue growth, with system and application software averaging a 19.56% CAGR in revenues over the past five years and internet software companies averaging 29.18%. Expected revenue growth over the next five years is more moderate: around 12% for traditional software and nearly 18% for internet software.
General retail is far slower, with a five-year historical revenue CAGR of about 10% and expected future growth closer to 4% annually. Healthcare products stand out with an expected five-year revenue growth rate of nearly 35%, driven largely by biotech and medical device innovation.
If your projected growth rate significantly exceeds your industry’s benchmark, you should have a specific, defensible reason. Maybe you’re entering an underserved niche, or you’ve secured a major contract. Without that justification, the benchmark is probably more accurate than your optimism.
Choosing the Right Time Horizon
The further out you project, the less reliable any single number becomes. A one-year revenue projection built on bottom-up data and recent trends can be reasonably accurate. A five-year projection is a rough directional estimate. A ten-year projection is closer to a thought exercise.
For investment growth projections, longer time horizons are more forgiving because short-term volatility tends to average out. A stock portfolio might lose 20% in one year and gain 25% the next, but over 20 years, the CAGR smooths into a more predictable range.
For business projections, keep your detailed forecasts to one or two years and use broader assumptions for years three through five. If you’re building projections for investors or a loan application, present your numbers as ranges rather than single points. A projection that says “we expect revenue between $800,000 and $1.1 million” signals more sophistication than one that claims exactly $950,000.
Whatever method you choose, document your assumptions. The growth rate, the inflation adjustment, the market share estimate: write them down. When actual results come in, comparing them to your assumptions tells you where your model was wrong and how to improve the next projection.