How to Compare Broker Commissions — Step by Step

Broker commissions have a direct impact on the profitability of your investments. Even small differences in fees accumulate over many transactions and can consume a significant portion of your gains. In this guide, we show you what to look for and how to use our commission analyzer to choose the cheapest broker for your investment style.

8 min readUpdated: 6.03.2026

Why compare commissions?

The difference between the cheapest and most expensive broker for a portfolio of 100 trades per year can amount to PLN 2,000-5,000. This is particularly important for active traders executing many transactions per month. When comparing brokers, it's not enough to look only at the per-trade commission — hidden fees (spread, FX charges, inactivity fee, custody fee) can double the total cost.

What to look for when comparing?

When choosing a broker, it's worth analyzing four main cost categories that can significantly impact your investment returns:

  • Transaction commissions — a fee charged for each buy or sell trade. Can be per-share (e.g., $1/trade) or percentage-based (e.g., 0.15% of value)
  • FX conversion fees — the cost of currency exchange for transactions on foreign markets. Typically 0% to 1.5% of the amount
  • Custody fees — some brokers charge an annual fee for account maintenance or asset custody
  • Inactivity fees — some brokers charge a fee when you don't execute transactions for a period of time (e.g., EUR 10/month)

How to use the commission analyzer?

Our commission analyzer lets you compare costs across 6 brokers based on your actual transactions or specified parameters. Here's how to use it:

  1. 1Open the commission analyzer at /analizator-prowizji
  2. 2Upload a CSV file with transactions from any supported broker, or enter the number and average value of trades
  3. 3The system will automatically calculate costs at each of the 6 brokers using current tariffs
  4. 4Compare results in the table — you'll see total commissions, FX fees, and savings from switching brokers

Comparison example with real numbers

For a portfolio with 50 trades per year averaging PLN 5,000 on the US market: IBKR (Interactive Brokers) charges about PLN 50-75 in commissions + low FX fees (0.002%). XTB offers 0% commission on stocks up to EUR 100,000 monthly turnover, but the FX fee is 0.5%. Trading 212 — 0% commission, but spreads can be higher. The annual difference can reach PLN 500-2,000 depending on frequency and volume.

Hidden fees to watch out for

Beyond explicit commissions, many brokers charge fees that aren't visible at first glance: spread (the difference between buy and sell price) — especially significant with CFD brokers and on forex; fees for foreign dividend conversions; fees for transferring your portfolio to another broker; fees for real-time market data. Check the broker's full fee schedule before opening an account.

Use our commission analyzer at /analizator-prowizji to check real costs for your transactions. You can upload a CSV file or enter data manually — the comparison takes less than a minute.

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