Commission and fee converter: rates, flat fees, and per-unit charges
A commission and fee converter helps you translate the same cost between percentage rates, fixed add-ons, flat fees, and per-unit charges. Enter the gross amount and whichever fee structure you know, and the calculator shows the matching fee amount, net proceeds, basis points, per-mille rate, variable fee, and fixed-fee component so the numbers are easier to compare.
How the calculator converts commission structures
In rate mode, the fee is calculated as a percentage of the gross amount. In flat-fee mode, the entered fee is treated as the total charge and then converted into an implied percentage rate. In per-unit mode, the total fee is the number of units multiplied by the fee charged for each unit.
After the fee amount is known, the remaining outputs are different views of the same underlying charge. Effective rate, basis points, and per mille are all just alternative ways to describe how large the fee is relative to the gross amount.
Commission fee = Gross amount × Rate
Used when the charge is given as a percentage of the transaction value.
Commission fee = Units × Fee per unit
Used when the charge depends on each unit, share, item, or ticket sold.
Converts a known fee amount back into an implied percentage rate.
Why multiple fee expressions matter
Different industries quote fees in different ways. Brokers may disclose percentages or basis points, marketplaces may charge a flat fee plus a variable percentage, and some sales channels use a charge per unit sold. Converting each structure into a common view makes it easier to compare offers and understand what you actually keep.
Basis points are especially useful when the fee is small. A 0.75% fee may look abstract, but 75 basis points often feels easier to compare against another offer at 50 basis points or 120 basis points.
Percentage plus fixed fee examples
Many platform fee and payment processing fee schedules are not just one percentage. A common structure is a percentage of the sale price plus a fixed transaction fee, such as a payment processor charging a variable rate plus a small per-order add-on. The fixed add-on matters most on smaller transactions because it pushes the effective rate above the headline percentage.
For example, a 2.9% fee plus a 0.30 fixed add-on is not simply 2.9% on a 100 gross amount. The variable fee is 2.90, the fixed add-on is 0.30, the total fee is 3.20, and the effective fee rate is 3.20%. Showing the variable and fixed pieces separately makes it easier to explain why small orders can feel more expensive than the advertised rate suggests.
Used when a marketplace, broker, payment processor, or platform combines a percentage commission with a fixed transaction fee.
Net proceeds = Gross amount − Total fee
Shows what remains after the combined fee is deducted.
What the outputs tell you
The headline figure is the total fee amount. Net amount shows what remains after the fee is deducted from the gross amount. Effective rate, basis points, and per mille show how heavy the fee is relative to the full transaction value.
Variable fee and fixed add-on split the total fee into the part that scales with the gross amount and the part that stays fixed. That split is useful when comparing two offers where one provider advertises a lower percentage but adds a larger fixed charge.
If you enter units in flat-fee or rate mode, the calculator also shows the equivalent fee per unit. That is helpful when you want to compare a flat platform charge with another provider that prices each item or transaction separately.
Frequently asked questions
What is the difference between percentage points and basis points for fees?
Basis points are just a smaller scale for the same fee rate. One percentage point equals 100 basis points, so a 0.75% fee is 75 basis points.
When is a flat fee better than a percentage fee?
A flat fee is often better for larger transactions because the charge does not rise with the gross amount. A percentage fee can be cheaper on smaller transactions. This calculator helps you compare those structures on the same transaction size.
Why does the effective rate change when I use a flat fee?
Because the flat fee stays constant while the gross amount changes. A £20 fee is 20% of £100, but only 2% of £1,000.
Does the calculator include taxes or extra platform charges?
No. It only converts the fee structure you enter. If a service also charges taxes, handling fees, or payment-processing costs, those should be added separately in your comparison.
How do I calculate a percentage fee plus a fixed transaction fee?
Choose rate mode, enter the gross amount, enter the commission or platform fee rate, and add the fixed add-on. The calculator separates the variable fee from the fixed add-on and then shows the combined total fee, net proceeds, and effective rate.
Why is the effective fee rate higher than the advertised percentage?
A fixed add-on increases the total fee without increasing the gross amount. On smaller transactions, that fixed charge can add a noticeable amount to the effective rate, even if the headline percentage is low.
