Trading Commission Calculator
Calculate broker commission on a trade under percentage, flat or tiered structures.
Please note: Trading carries substantial risk of loss. These calculators are planning tools, not trading advice, and no position sizing method prevents losses.
What the Trading Commission Calculator does
Brokers charge commission as a percentage of trade value, a flat fee, or a rate per share — often with a minimum that dominates on small trades. Knowing the structure tells you the smallest trade size that makes economic sense.
Formula
Percentage: Commission = Trade value × Rate ÷ 100Per share: Commission = Shares × Rate per shareApplied = max(Calculated, Minimum), doubled for a round trip
Inputs explained
| Input | Unit | Required | Notes |
|---|---|---|---|
| Trade value | selected currency | Yes | Accepts more than 0. |
| Commission type | one of 3 options | Yes | — |
| Rate | % | In some modes | Shown Commission type is Percentage. |
| Flat fee | selected currency | In some modes | Accepts 0 or more. Shown Commission type is Flat fee. |
| Fee per share | selected currency | In some modes | Accepts 0 or more. Shown Commission type is Per share / unit. |
| Number of shares | number | In some modes | Accepts more than 0. Shown Commission type is Per share / unit. |
| Minimum commission | selected currency | Optional | Accepts 0 or more. |
| Apply to | one of 2 options | Yes | — |
| Currency | one of 10 options | Optional | — |
How to use it
- Choose Commission type and Apply to.
- Enter Trade value.
- Fill in the remaining inputs the form shows for your choice.
- Optionally add Minimum commission.
- Select Calculate.
Worked example
A $12,000 trade at 0.1% commission, both sides.
- Value
- 12000
- Type
- Percentage
- Rate
- 0.1
- Sides
- Both
$12 per side, $24 round trip — 0.2% of the trade value.
Frequently asked questions
Is zero-commission trading really free?
Not usually. Brokers offering it typically earn from payment for order flow or wider spreads, so the cost moves from an explicit fee to a slightly worse fill price.
Method and sources
Method. Commission by the model selected — percentage of value, per share or unit, or flat fee — with any minimum applied.
Assumptions
- One model applies to the whole trade, and the minimum is per order.
Limitations
- A per-share rate with a minimum is punitive on small orders: the minimum can exceed several per cent of a small position, which the percentage view hides.
- Commission is one component. Exchange, clearing and regulatory fees are levied separately in many markets.