Your account balance went up. That part is easy to see. But how much of that increase came from the investment actually growing, and how much came from you simply putting more money in? A basic percentage-growth calculation can't tell the difference. It treats every dollar in your ending balance as "return".
This is the gap that the CAGR Calculator With Extra Cash Flows is built to close. It calculates your Compound Annual Growth Rate (CAGR) the standard way when there's no extra money involved, and it also lets you factor in yearly contributions or withdrawals so the growth rate you get back reflects the investment itself.
Below, we'll walk through what the calculator actually does, how to use each field correctly, the math running underneath it explained in plain terms, and a short story that shows the whole thing in action.
What CAGR Actually Measures
CAGR stands for Compound Annual Growth Rate. It answers one specific question: if this investment had grown at exactly the same rate every single year, what would that rate have to be to take it from its starting value to its ending value?
It's a smoothing tool. Real investments rarely grow in a straight line — some years are up 20%, some years are down 5%. CAGR ignores that bumpy path and gives you the single steady rate that would have produced the same end result. That's what makes it so useful for comparing two very different investments, or for comparing your own results year to year.
The catch is that ordinary CAGR only works cleanly when the only thing that changed your balance was investment performance. The moment you start adding or removing cash from the account, the ending value stops being a pure measure of growth and that's where the "extra cash flows" version of the calculator earns its keep.
How to Use the Calculator, Step by Step
The tool has five input fields. Here's what to put in each one and why it matters.
- Beginning Value ($). This is your starting point — the balance on day one, or your original investment amount. If you opened a brokerage account with $5,000, that's your Beginning Value.
- Ending Value ($). This is the balance on the last day of the period you're measuring, exactly as it actually stood. Don't try to subtract your contributions or add back your withdrawals yourself — enter the real, final number and let the calculator handle the adjustment.
- Number of Years. The length of time between the two values above. This doesn't have to be a whole number — 3.5 years or 7.25 years both work fine.
- Additional Contributions ($ per Year). If you added money regularly — say, $200 a month, which is $2,400 a year — enter the yearly figure here. Leave it at 0 if you never added anything after the initial investment.
- Additional Withdrawals ($ per Year). The mirror image of the field above. If you pulled money out periodically, enter how much per year. Leave at 0 if you never withdrew anything.
Once those five fields are filled in, the calculator returns your CAGR, the total growth, and a breakdown of your total contributions and withdrawals over the period, so that you can see exactly how much of your ending balance, the cash you moved yourself, and how much was the investment doing the work.
The Formula, Broken Down Simply
There are really two formulas at play here, and the second one is just the first one with a cleanup step added beforehand.
1. The standard CAGR formula (used when contributions and withdrawals are both zero):
In words: divide the ending value by the beginning value to see how many times over your money grew. Raise that to the power of "1 divided by the number of years" — this is the step that spreads the growth out evenly across each year instead of lumping it all together. Subtract 1 to turn it into a percentage.
2. The adjusted formula (used the moment either contribution or withdrawal field is greater than zero):
Before the calculator can apply the formula above, it needs to strip out the effect of the money you moved in and out, since that cash was never part of the investment's own growth. It does this in two small steps:
Total Withdrawals = Withdrawal per Year × Years
Adjusted Ending Value = Ending Value − Total Contributions + Total Withdrawals
Then the same CAGR formula from step 1 runs on that adjusted number:
One honest caveat worth knowing: this method assumes your contributions and withdrawals were spread evenly across the period and simply nets them against the ending balance. It doesn't account for the exact date each deposit or withdrawal happened, so it's an approximation rather than a precise money-weighted return.
Visual Walkthrough: How the Numbers Flow
The numbers above match the walkthrough story in the next section.
The numbers above match the walkthrough story in the next section.
A Simple Story: Marcus and His Six-Year Investment
Marcus opened a brokerage account and put in $8,000 to start. Over the next 6 years, two things happened at the same time: the investments inside the account grew, and Marcus kept managing his own cash flow around the account — adding $400 a year from his savings, and pulling out $200 a year to cover a recurring expense.
At the end of the six years, Marcus checked his balance: $15,200. His first reaction was to divide the ending value by the beginning value and assume the account had nearly doubled through pure performance. But that number includes his own deposits and withdrawals mixed in with the actual investment growth, so it overstates how well the underlying investment really did.
Here's what happens when he runs it through the CAGR Calculator With Extra Cash Flows:
- Total Contributions = $400 × 6 years = $2,400
- Total Withdrawals = $200 × 6 years = $1,200
- Adjusted Ending Value = $15,200 − $2,400 + $1,200 = $14,000
- CAGR = (14,000 ÷ 8,000) ^ (1/6) − 1 = 1.75 ^ 0.1667 − 1 ≈ 9.78%
Compare that to what the naive, unadjusted math would have told him: (15,200 ÷ 8,000) ^ (1/6) − 1 ≈ 11.29%. That's a meaningful gap — about a page and a half of percentage points that actually came from Marcus's own saving and spending decisions, not from the investment itself.
The corrected 9.78% figure is the number Marcus should actually trust if he wants to compare this account against an index fund, a different broker, or his own target return. It's lower than the flashy headline number, but it's the honest one.
Why This Adjustment Matters More Than People Think
It's tempting to skip this step, especially when the raw growth number looks good. But mixing contributions into a growth-rate calculation causes two specific problems:
It makes disciplined savers look like better investors than they actually are. Someone who deposits money faithfully every month will always show a bigger raw balance increase than someone who doesn't — regardless of which one picked better investments.
It breaks comparisons between accounts. If you're comparing two portfolios and only one of them received regular deposits, an unadjusted growth percentage isn't comparing investment performance at all — it's partly comparing your own cash habits.
Separating the two lets you answer two different, equally useful questions: "How much did I save?" and "How well did that money perform once it was invested?" Those are not the same question, and this calculator is built to answer the second one cleanly.
Common Questions
Is this the same as average annual return?
No. A simple average adds up each year's percentage change and divides by the number of years, which overstates results because it ignores compounding. CAGR is the compounded rate, which is a more accurate reflection of how money actually grows over time.
Can the result come out negative?
Yes. If your adjusted ending value is lower than your beginning value — for example, if the investment lost money even after accounting for what you added or withdrew — the calculator will show a negative percentage.
Does this tell me what will happen in the future?
No. CAGR only describes what already happened over a specific stretch of time. It's a backward-looking measurement, not a forecast, and past growth is never a guarantee of future results.
What if my withdrawals happened at irregular times, not evenly throughout the year?
This calculator assumes contributions and withdrawals are spread evenly across the period. If your cash flows happened at very specific, uneven dates and you need an exact, date-sensitive return, a full XIRR calculation will be more precise. For a fast and realistic estimate, this method works well for the vast majority of everyday situations.
Should I subtract my withdrawals from the Ending Value myself before entering it?
No — enter your real, actual final balance in the Ending Value field. Put your withdrawal amount in the "Additional Withdrawals" field instead, and the calculator will handle the adjustment for you automatically.
Related Calculators
If you found this useful, these other tools on the site work well alongside it:
- Compound Interest Calculator — project how a balance grows forward in time, rather than measuring past growth.
- Investment Return Calculator — a broader look at total and annualized returns.
- Discounted Cash Flow (DCF) Calculator — estimate what future cash flows are worth today.
- Reverse DCF Calculator — work backward from a current price to the growth assumptions it implies.
- Retirement Savings Goal Calculator — see how steady contributions build toward a target number.
- Retirement Age Calculator — estimate when your savings rate gets you to retirement.
- WACC Calculator — for a company-level view of the cost of capital behind investment decisions.
Disclaimer: This article and the linked calculator are for general educational purposes only and are not financial, investment, or tax advice. Actual results depend on your specific circumstances, fees, taxes, and market conditions. Speak with a qualified financial professional before making investment decisions.