The phrase "a percentage based on" is correct and usable in written English.
You can use it when discussing calculations or evaluations that rely on a specific reference point or data set.
Example: "The final score will be calculated as a percentage based on the total number of correct answers."
Alternatives: "a proportion derived from" or "a fraction calculated from".
That is in addition to eBay's commission, which is also a percentage based on the final selling price.
Instead of your tipping me based on what you think of my service, I will calculate a percentage based on how I think you did as customers.
It would be very good if the number of each delegate from the arab countries is calculated as a percentage based on the population of each country!
Spreads typically vary from 12.5 cents to 50 cents, an amount that adds up to a sizable profit for brokers, who take in a percentage based on the size of the spread.
The transportation bill changed the way the gas tax is assessed from a flat tax of 17.5 cents per wholesale gallon to a percentage based on the average price over a six-month period.
Mr. Janicke, Mr. Kearns's attorney, argued that Mr. Kearns should receive a substantial percentage of the selling price that Ford charged dealers for the wiper, a percentage based on historic profitability.
We suggest the enactment of an oil security tax, a fixed percentage based on the price of a barrel of oil and paid by oil companies for every barrel produced in or imported into the United States.
These maps show a turnout percentage based on two numbers for each county: ballots cast in the 2016 presidential race and the estimated population of voting-age citizens.
Each creditor is owed a different percentage based on the type of loan it gave and which division the creditor gave it to.
Under the proposal, the outside firm would pay Glendale Community College Associated Students a commission percentage based on net sales.
Every insurance company uses a different percentage based on their policies and procedures in assessing the damage of the salvaged car.
