Calculadora de IMC

The arithmetic behind a tip

A tip is a percentage of the bill, and the math is short: tip = bill × (percent ÷ 100), and total = bill + tip. This calculator does exactly that, then divides both numbers by how many people are splitting. So with a $50 bill, an 18% tip is 50 × 0.18 = $9, the total is $59, and split between two people each owes $29.50, of which $4.50 is their share of the tip. Every figure updates the instant you change the bill, the percentage, or the headcount, so you can see how each input moves the result. You can tap a preset (10%, 15%, 18%, 20%, or 25%) or type any custom percentage, and the people counter runs from 1 to 20.

A worked example with an awkward number

Real bills are rarely round. Say dinner comes to $73.40, you want to leave 20% for good service, and you are splitting three ways. The tip is 73.40 × 0.20 = $14.68, making the total $88.08. Divided by three, each person's total is $29.36 and each person's tip share is about $4.89. Because three doesn't divide $88.08 evenly to the cent, the displayed per-person figures are rounded to two decimals — so three people paying $29.36 each comes to $88.08, which happens to match here, but with other amounts the rounded shares can sum to a cent or two off the exact total. When that happens, one person rounds up by a penny. It is a real limitation of splitting any amount that isn't cleanly divisible.

How much to tip, and on what

Tipping norms are cultural, not mathematical, and they vary widely by country. In the United States, where tipping is deeply ingrained, common guidance for table service is 15% as a floor for adequate service, 18% as a typical default, 20% for good service, and more for exceptional. Counter service, coffee, and bars tend to see 10–15% or a flat amount. In much of Europe and Asia, service is often included or a small rounding-up is normal, and a US-style 20% would be unusual. A recurring question is whether to tip on the pre-tax or post-tax amount: tipping on the pre-tax subtotal is the more defensible choice, since a tip rewards service rather than the government's sales tax, though many people simply apply the percentage to the final total for convenience. This tool applies your percentage to whatever bill figure you enter, so you control which base you use.

Genuine use cases

• Group dinners. The split feature turns "who owes what" from a napkin-math argument into a single number per person.
• Quick sanity checks. Before signing a receipt, confirm the suggested tip line actually matches the percentage you intend to leave — printed suggestions are sometimes calculated on the post-tax total.
• Budgeting a night out. Work backward: if you can spend $40 total per person at 20% tip, the pre-tip bill per person is about $33.
• Services beyond restaurants. The same percentage math applies to taxis, haircuts, delivery, and tour guides.

Tips for getting it right

• Round up for simplicity. If the math gives $4.89 per person, agreeing to round each share to $5 makes collection painless and slightly over-tips, which servers appreciate.
• Decide the base before you start. Pick pre-tax or post-tax and enter that figure as the bill so everyone is calculating the same way.
• Watch for an auto-gratuity. Large parties are often charged a mandatory service fee already on the bill. Tipping again on top is double-tipping unless you intend extra.
• Carry the remainder fairly. When a split doesn't divide evenly, rotate who absorbs the extra penny rather than always sticking the same person with it.

Common mistakes

The most frequent error is tipping on a total that already includes a service charge, effectively paying the gratuity twice. The second is reading a payment terminal's suggested amounts without checking whether they were computed on the pre-tax or post-tax figure — a 20% suggestion on a tax-inflated total quietly costs you more than 20% of the food. The third is forgetting that a percentage of a larger bill is a larger tip in dollars, so the same 18% feels very different on a $20 lunch than a $200 dinner. This calculator keeps all three honest by showing the exact tip in dollars alongside the percentage, computed entirely in your browser with nothing sent to any server.