How to Calculate Portfolio CAGR Across Multiple Brokers

Why Calculating CAGR Across Multiple Brokers Is Harder Than It Looks

If you hold investments at two or more brokers — say DEGIRO for European ETFs and Interactive Brokers for US stocks — you have probably tried to answer a simple question: what is my actual annualized return across everything?

The standard CAGR formula is straightforward. Take your ending value, divide by your beginning value, raise it to the power of 1/n (where n is the number of years), and subtract 1. But this clean formula breaks the moment you have multiple accounts with different start dates, ongoing deposits, withdrawals, and transfers between brokers.

The real problem is not the math. It is getting clean, consistent data from each broker and combining it correctly. Each platform reports returns differently, uses different date formats, and includes or excludes fees in inconsistent ways. Without solving this data problem first, any CAGR number you calculate is unreliable.

The CAGR Formula and When It Actually Works

CAGR stands for Compound Annual Growth Rate. According to Investopedia, it measures the annualized rate of return between a beginning and ending value, assuming profits are reinvested. The formula is: CAGR = (Ending Value / Beginning Value)^(1/n) - 1, where n is the number of years.

This formula works perfectly when you have a single lump-sum investment with no additional contributions or withdrawals. You invested 10,000 EUR three years ago, it is now worth 13,300 EUR, and your CAGR is approximately 10%. Clean and accurate.

But most real portfolios do not look like that. You contribute monthly. You occasionally withdraw. You might transfer shares between brokers. You receive dividends that may or may not be reinvested. In these cases, naive CAGR gives you a misleading number — sometimes dramatically so.

Why Naive CAGR Misleads Multi-Broker Investors

Here is a concrete example of how naive CAGR can be wildly wrong. Say you started with 5,000 EUR in January 2023. Over the next two years, you added 1,000 EUR per month across two brokers. By January 2025, your total portfolio value is 32,000 EUR.

Naive CAGR calculation: (32,000 / 5,000)^(1/2) - 1 = 153%. That looks incredible — but it is completely wrong. Most of that 32,000 is money you deposited, not investment returns. Your actual investment return might be closer to 8-12%.

This is the single most common mistake retail investors make when measuring performance. And it gets worse with multiple brokers, because you might calculate an inflated CAGR for each account separately and then have no way to combine them into a meaningful total.

Money-Weighted Return: The Right Approach for Real Portfolios

For portfolios with ongoing cash flows, you need money-weighted return (MWR), also called the internal rate of return (IRR). This method accounts for the timing and size of every deposit and withdrawal.

The money-weighted return finds the discount rate that makes the present value of all cash flows (deposits, withdrawals, and the final portfolio value) equal to zero. It answers the question: given when and how much I actually invested, what annualized return did my money earn?

To calculate MWR across multiple brokers, you need a complete timeline of every cash flow across all accounts. That means: initial deposits at each broker, every subsequent contribution, every withdrawal or transfer, dividend payments (if withdrawn rather than reinvested), and the current value of each account.

This is mathematically straightforward but practically painful. You need to export transaction histories from each broker, normalize the dates and currencies, identify transfers between accounts (so you do not double-count them), and then run the IRR calculation on the combined dataset.

Step-by-Step: Calculating Portfolio CAGR Across Brokers Manually

If you want to calculate your true CAGR across multiple brokers by hand, here is the process. Be warned — it is tedious but doable for investors who want full control over their numbers.

• Step 1: Export transaction history from each broker. From DEGIRO, use the account statement CSV. From IBKR, set up a Flex Query for trades and cash transactions. From Trading 212, export your transaction history CSV.
• Step 2: Normalize all transactions into a single timeline. Convert everything to one base currency using the exchange rate on the transaction date. Tag each transaction as deposit, withdrawal, dividend, buy, or sell.
• Step 3: Identify and remove internal transfers. If you moved 5,000 EUR from DEGIRO to IBKR, that shows as a withdrawal in one account and a deposit in the other. For your combined portfolio, these cancel out and should not appear as cash flows.
• Step 4: Calculate the current total portfolio value across all accounts. Include cash balances, not just invested positions.
• Step 5: Use the XIRR function in a spreadsheet (Google Sheets or Excel) to calculate the annualized money-weighted return. Enter each cash flow with its date — deposits as negative numbers, the current total value as a positive number on today's date.
• Step 6: The XIRR result is your true annualized portfolio CAGR adjusted for all cash flows.

Common Pitfalls When Combining Broker Data for CAGR

Even if you follow the steps above, several pitfalls can produce inaccurate results.

• Double-counting transfers: The most common error. If you transferred shares or cash between brokers, failing to remove both sides of the transfer will inflate your CAGR.
• Ignoring fees: Some broker exports show trades net of fees, others show them separately. If you are not consistent about whether fees are included in your cost basis, your return calculation will be off.
• Currency inconsistency: If you hold EUR-denominated ETFs at DEGIRO and USD stocks at IBKR, you need to decide whether you are measuring returns in your home currency or each position's native currency. Most investors should use their home currency.
• Missing dividend data: Some brokers do not include dividends in basic transaction exports. If dividends were paid but not captured in your data, your CAGR will understate actual returns.
• Incorrect date handling: DEGIRO uses DD/MM/YYYY, IBKR uses YYYY-MM-DD. A date format mismatch can silently corrupt your entire calculation.

How TrackYourPortfol.io Solves the Multi-Broker CAGR Problem

The manual process works, but it is fragile, time-consuming, and needs to be repeated every time you want an updated number. This is exactly the problem TrackYourPortfol.io was built to solve.

You can track all of this automatically with TrackYourPortfol.io. Connect your broker accounts, and the platform aggregates all transactions — buys, sells, deposits, withdrawals, dividends, and fees — into a single normalized timeline. It handles currency conversion, identifies internal transfers, and calculates your true money-weighted return across your entire portfolio. If your next question is what those returns look like after commissions, FX, withholding tax, and other drag, read our guide to real portfolio returns after fees. If you are also deciding whether the issue is measurement or broker cost, compare your setup with the broker fee comparison tool and estimate drag with the hidden investment fees calculator.

Instead of spending hours with spreadsheets every quarter, you get an always-current, accurate CAGR that reflects your actual investment performance. No double-counting, no missed dividends, no currency errors.

For investors with positions at DEGIRO, Interactive Brokers, Trading 212, or other European brokers, this eliminates the single biggest barrier to knowing whether your portfolio is actually performing well — or just growing because you keep depositing money.

CAGR vs Other Return Metrics: Which One Should You Track?

CAGR (specifically money-weighted CAGR) is the most intuitive return metric for individual investors because it answers the question most people actually care about: how well has my money done?

However, it is worth knowing the alternatives. Time-weighted return (TWR) removes the effect of cash flow timing and measures the performance of your investment strategy itself, independent of when you added money. This is what fund managers report, because it isolates investment decisions from deposit timing.

For most retail investors managing their own money, money-weighted return (CAGR adjusted for cash flows) is more useful. It captures the reality that investing a large sum right before a crash hurts your actual returns, even if your fund selections were fine.

The ideal setup is tracking both: money-weighted return to know how your actual wealth is growing, and time-weighted return to evaluate whether your investment strategy is working. This gives you a complete picture of performance — which is exactly what institutional investors have always had, and what serious retail investors deserve too.