Compound growth rate

A mid-stage SaaS company was at £10M ARR with 35% CAGR. To raise Series C at target valuation, they needed to show a path to 100M+ ARR within 5 years. They modelled: current 35% CAGR reaches only £50M by year 5. They needed to accelerate. The model showed if they launched a new product line (projected 60% CAGR in year 1), combined with improved retention, overall CAGR could reach 55%, reaching £55M by year 5. This model guided where to invest and what to pitch to investors.

Demonstrates sustainable growth momentum

Year-to-year spikes don't mean much. One large customer might inflate annual growth to 100%, then churn causes next year's growth to be negative. CAGR smooths these volatilities and shows whether you're building a scalable business. Investors prefer steady 40% CAGR to volatile 100%, 10%, 80%, because steady growth is predictable.

Guides long-term strategy and fundraising

If your current CAGR is 30% but your goal is 50%, you know product, sales, or marketing needs to improve. You can model: what changes would get us to 50%? This guides investment priorities. For fundraising, CAGR is the primary metric VCs evaluate. A startup at £1M ARR with 100% CAGR is more valuable than a startup at £1M ARR with 20% CAGR because the 100% company will reach £10M faster.

Predicts future scale and profitability

If your CAGR is 40% and you're at £5M ARR, you can predict reaching £50M in approximately 6 years (assuming CAGR holds). This projection guides long-term planning: when will you need more engineering? Sales? Finance teams? CAGR-based projections help you plan headcount and budget growth.

A fintech company had been growing at 80% CAGR from 2021-2023. Looking at 2024 data, overall CAGR had dropped to 40%. Investigation showed two customer segments had inverted: their core segment was churning faster as competitors launched better products. Their CAGR decline was an early warning that product needed urgent improvements. Without CAGR tracking, they wouldn't have noticed the trend until cash flow problems emerged.

A SaaS startup started 2022 at £100K ARR. End of 2023: £500K. End of 2024: £2.2M. CAGR: (2.2M/100K)^(1/2) - 1 = 1480% over 2 years, or approximately 148% annualised. This explosive CAGR demonstrated product-market fit and helped them raise Series A at a high valuation. By 2025, CAGR had moderated to 60% as the company scaled, still strong but more sustainable.

Calculate CAGR from your revenue or customer data

Identify your baseline (revenue/customers at start) and endpoint (now), and the number of years between them. Use a financial calculator or spreadsheet (Excel formula: =POWER(Ending Value/Beginning Value, 1/Years)-1). Document your CAGR quarterly so you see if it's improving or declining.

Track CAGR by business unit or product line

Your overall company CAGR might be 30%, but one product line might be 80% and another 10%. Segmented CAGR reveals which parts of your business are healthy and which are dying. Invest in high-CAGR products; sunset or restructure low-CAGR products.

Set CAGR targets aligned with fundraising goals

Fundraising requires showing trajectory. If you're raising Series A, investors expect 60%+ CAGR. Series B might be 40%+. Benchmark against your stage. Set targets and measure progress quarterly. CAGR becomes your north star for board meetings and investor updates.

Model scenarios: what changes achieve target CAGR?

If you're at 25% CAGR but need 40% to hit fundraising targets, what has to change? More sales reps? New product line? Better retention? Build a model: 'If we improve retention by 5%, CAGR improves to X'. These scenarios guide investment decisions.

Compound growth rate is the steady annual rate a metric would have to grow at, every year, to get from where it started to where it is now. The proper name is CAGR, compound annual growth rate. The word "compound" is the whole point: each year's growth builds on the bigger base the last year left behind, the same way interest compounds in a savings account.

It's different from year-on-year growth, which only compares two consecutive years and gets thrown off by a single good or bad period. CAGR smooths the bumps into one clean number. Say your ARR was £1m in 2022, £1.5m in 2023 and £2.2m in 2024. Your three-year CAGR is roughly 48% a year, the constant rate that would have carried you along that exact path.

The maths is simple: CAGR = (ending value ÷ starting value) ^ (1 ÷ number of years) − 1. You only need three things, the start, the end, and how many years apart they are.

Why founders and investors care: CAGR tells you whether you're building momentum or just got lucky once. A company doing a steady 60% a year is more valuable than one bouncing between 200%, 10% and 80%, because steady compounding is predictable and compounds into something huge. As a rough read: 40%+ is exceptional, 20% is solid, under 10% means growth is stalling.

A few ways this shows up in practice:

Tracking it as it happens. Say you're piping your monthly recurring revenue into Databox and you build a board metric that recomputes your trailing CAGR each month. The moment that line bends down, you see it, long before it hits your bank balance, and you can dig into which segment is slowing.

Pulling the actual numbers. Say your revenue lives in Moneybird. Export your yearly turnover, drop the starting and ending figures into the formula, and you've got a CAGR grounded in real invoiced money rather than a hopeful forecast. Do this per product line, not just company-wide, one line might be compounding at 80% while another quietly dies at 5%.

Modelling the fundraise. Say you're at £10m ARR and 35% CAGR, and you need a credible path to £100m for a Series C. Build the scenario in Looker Studio: at 35% you only reach about £50m in five years. Add a new product line and better retention, watch blended CAGR climb to ~55%, and now you can show investors exactly which levers get you there.

The formula takes a second; understanding what the number is telling you is what actually drives the strategy.