How to split a restaurant tip and read profit margin vs markup
Tip on the bill you mean, then stop mixing margin with markup when you price a product.
Tip is a percent of whatever you typed
Toolora’s Tip Calculator takes bill × (percent / 100) as the tip, adds it for a grand total, then divides by the number of people. Example: bill 64.50, 18%, two people → tip 11.61, total 76.11, 38.06 each (two-decimal money). If Bill is the pre-tax subtotal, the tip is pre-tax. If you paste a taxed total, the tip is on the taxed total. The page does not add sales tax. Shares are not rounded to coins so you can round at the table. One person is allowed. Uneven splits (one guest had drinks) are manual: compute the even share, then settle extras.
Margin is not markup
Profit Margin Calculator reports three numbers from cost and selling price. Profit is revenue − cost. Margin is profit / revenue. Markup is profit / cost. Cost 40 and revenue 65 is profit 25, margin 38.46%, markup 62.50%. Pricing by “add 50% to cost” is markup, not a 50% margin (that would require doubling cost). Revenue cannot be zero for margin; cost cannot be zero for markup. A loss still computes — percentages go negative.
When to use Discount instead
Discount Calculator starts from a list price and a percent off. That is the customer-facing inverse of a markup, not a cost-based margin. Percentage Calculator is the generic percent-of / increase / decrease toolbox. Keep restaurant bills and wholesale costs on the matching page so the formula matches the story.
Privacy
Bills and costs never leave the browser. Related: Loan Calculator when the percent is an APR rather than a tip. This is not accounting or tax advice.