How to Use This Calculator
- 1
Enter the Number of Shares
Input the number of shares you plan to buy or sell in this trade.
- 2
Enter the Share Price
Input the current market price per share. The calculator derives the trade value automatically (shares times price).
- 3
Review your results
Review the Commission Fee, Effective Rate, Round-Trip Cost, Breakeven Move, Net Buy Cost, and Net Sell Proceeds. After calculating, use Recent to revisit previous scenarios.
Example Calculation
A trader wants to calculate the IBKR Pro commission for buying 100 shares of a stock priced at $50 per share.
Number of Shares
100
Share Price
$50
Results
Commission Fee
$0.35; Effective Rate: 0.0070%; Round-Trip Cost: $0.70; Breakeven Move: $0.0070; Net Buy Cost: $5,000.35; Net Sell Proceeds: $4,999.65.
Tips
Know when the minimum kicks in
The $0.35 minimum applies whenever the per-share calculation (shares x $0.0035) is less than $0.35. That means any trade of 100 shares or fewer will always cost $0.35, regardless of the stock price.
Watch for the 1% cap on cheap stocks
If you trade many shares of a low-priced stock, the 1% cap can significantly reduce your fee. For example, 10,000 shares at $0.10 per share would calculate to $35 but gets capped at $1.00 (1% of the $100 trade value).
Use breakeven to size your trades
The Breakeven Move shows how far the stock price must move to cover round-trip commissions. In the default example, the stock only needs to move $0.007 per share — effectively negligible on a $50 stock.
Compare against zero-commission alternatives
IBKR Lite offers $0 commission for US stocks but uses payment for order flow, which may result in slightly worse execution prices. For the default 100-share trade, the $0.35 Pro commission is minimal — evaluate whether better execution quality justifies it.
Understanding IBKR Pro Commission Costs
The Interactive Brokers Fee Calculator estimates your commission under IBKR Pro's tiered pricing model.
Enter your shares and share price to see the commission, effective rate, round-trip cost, and breakeven move.
Interactive Brokers is one of the largest electronic brokerages, and its tiered pricing — $0.0035 per share with a $0.35 minimum and 1% cap — makes it competitive for both small and large trades.
For a typical 100-share trade at $50, the commission is just $0.35, representing a 0.0070% effective rate.
How Interactive Brokers Commissions Are Calculated
IBKR Pro uses a three-step commission formula for US stocks.
The per-share rate is applied first, then the minimum floor, and finally the trade value cap:
Trade Value = Number of Shares x Share Price
Calculated Fee = Number of Shares x $0.0035
Fee After Minimum = max(Calculated Fee, $0.35)
Commission Fee = min(Fee After Minimum, Trade Value x 0.01)
Effective Rate = (Commission Fee / Trade Value) x 100
Round-Trip Cost = Commission Fee x 2
Breakeven Move = Round-Trip Cost / Number of Shares
Net Buy Cost = Trade Value + Commission Fee
Net Sell Proceeds = Trade Value - Commission Fee
Number of Shares is the quantity traded, Share Price is the per-share market price, $0.0035 is the per-share rate, $0.35 is the minimum commission, and Trade Value x 0.01 is the 1% cap.
Calculating IBKR Pro Fees: A Worked Example
A trader wants to buy 100 shares of a stock priced at $50 per share using IBKR Pro's tiered plan.
Here's how the calculator processes this:
- Trade Value: 100 shares x $50 = $5,000.00
- Calculated Fee: 100 x $0.0035 = $0.35
- Apply Minimum: max($0.35, $0.35) = $0.35 — the minimum matches exactly
- Apply 1% Cap: min($0.35, $5,000 x 0.01) = min($0.35, $50) = $0.35
- Commission Fee: $0.35
- Effective Rate: ($0.35 / $5,000) x 100 = 0.0070%
- Round-Trip Cost: $0.35 x 2 = $0.70
- Breakeven Move: $0.70 / 100 = $0.0070 per share
- Net Buy Cost: $5,000 + $0.35 = $5,000.35
- Net Sell Proceeds: $5,000 - $0.35 = $4,999.65
The $0.35 commission represents just 0.007% of the trade value.
The stock only needs to move $0.007 per share — 0.014% of the $50 price — to cover a full round-trip.
This demonstrates why IBKR Pro's tiered pricing is popular among active traders.
IBKR Pro Volume Tiers and Discounts
IBKR Pro's tiered pricing offers lower per-share rates as monthly trading volume increases.
The standard rate of $0.0035 per share applies to the first 300,000 shares per month.
Beyond that, rates decrease in tiers — for example, 300,001 to 3,000,000 shares may drop to $0.0020 per share, and volumes above 20,000,000 shares can reach as low as $0.0015.
These volume discounts can meaningfully reduce costs for institutional and high-frequency traders, though most retail traders will operate within the standard tier.
Regulatory Fees Beyond the Commission
Beyond IBKR's commission, several pass-through fees apply to US equity trades.
The SEC charges a fee on sell transactions (currently $0.00008 per dollar of proceeds in 2026), and FINRA's Transaction Activity Fee (TAF) is $0.000166 per share sold.
Exchange fees vary by venue and can be positive (fee) or negative (rebate) depending on whether your order adds or removes liquidity.
For the default 100-share trade, these additional fees typically add less than $0.05, but they're worth monitoring for high-volume strategies where fractions of a cent per share compound.
Frequently Asked Questions
How does Interactive Brokers' tiered pricing work?
IBKR Pro tiered pricing charges $0.0035 per share, with a $0.35 minimum per order and a 1% of trade value cap. The fee is calculated as shares x $0.0035, then floored at $0.35 and capped at 1% of the trade value. For 100 shares at $50 ($5,000 trade), the fee is $0.35.
What is the difference between IBKR Pro and IBKR Lite?
IBKR Pro charges tiered commissions ($0.0035/share) but offers direct market access and better execution quality. IBKR Lite offers $0 commissions for US stocks and ETFs but routes orders through payment for order flow, which may result in slightly worse fill prices. Active traders and large orders typically benefit from Pro; casual investors may prefer Lite.
When does the 1% trade value cap apply?
The cap activates when the per-share calculation exceeds 1% of the trade value. This typically happens with low-priced stocks traded in large quantities. For example, trading 10,000 shares at $0.10 ($1,000 trade value) would calculate a $35 fee, but the 1% cap reduces it to $10.
What does Breakeven Move mean?
Breakeven Move is the minimum price change per share needed to cover round-trip commissions (buying and selling). It equals the round-trip cost divided by the number of shares. In the default example, $0.70 / 100 = $0.0070 per share — the stock must move at least $0.007 from your purchase price before you begin to profit.
Are there additional fees beyond the commission?
Yes. IBKR passes through exchange fees, clearing fees, and regulatory fees (SEC fee on sell orders, TAF fee). These are typically fractions of a cent per share and negligible for most retail trades, but they can add up for high-volume or institutional trading. Check IBKR's full fee schedule for current rates.