How do you calculate a 20% tip?

Multiply the bill by 0.20, or equivalently divide by 5. For a £75 bill: £75 × 0.20 = £15 tip, making the total £90. The mental shortcut is to find 10% (move the decimal left one place: £7.50) and double it.

Should you tip on the pre-tax or post-tax amount?

Convention in the US is to tip on the pre-tax amount, since the tip is a reward for service rather than for the government's tax. In practice the difference is small — typically £1–2 on an average restaurant bill — so many people simply tip on the total shown. Outside the US, where prices are tax-inclusive, this question does not apply.

How do you split a bill when people ordered different things?

The fairest approach is to add up each person's items individually and divide the tip proportionally. For simplicity, many groups use an equal split and make manual adjustments for large outliers — for example, the person who ordered the expensive wine covers the tip. Payment apps make item-level splitting much easier than doing it in your head.

What is the standard tip percentage in the US?

15–20% is standard for sit-down restaurant service in the US. 20% has become increasingly common as a baseline for good service. Below 15% is generally considered a poor tip; above 25% signals exceptional service. For other service types — bartenders, hotel housekeeping, taxi drivers — 15–20% is also the norm.

How to Calculate a Tip and Split a Bill Between Any Number of People

How to Calculate a Tip and Split a Bill: The Quick Answer#

To calculate a tip: multiply the bill by the tip percentage, then divide by 100. Tip amount = bill × tip% ÷ 100. To split the total (bill + tip) between a group: divide by the number of people. Example — a £90 bill with a 15% tip:

Tip: £90 × 15 ÷ 100 = £13.50
Total: £90 + £13.50 = £103.50
Per person (6 people): £103.50 ÷ 6 = £17.25

That's all there is to it. The free tip calculator at allio.tools handles this in seconds, including custom split counts and rounding options.

Standard Tip Percentages by Country and Context#

Tipping norms vary significantly around the world, and getting this wrong can cause embarrassment in either direction — over-tipping where it's unexpected, or under-tipping where it's relied on as income:

United States — 15–18% is standard for sit-down restaurants; 20% is generous; 25%+ for exceptional service. Tipping is near-mandatory as servers' base wages are often below minimum wage.
United Kingdom — 10–12.5% is typical; many restaurants automatically add a service charge. Check the bill before adding more.
Europe (broadly) — rounding up the bill or leaving 5–10% is appreciated but not expected. In some countries tipping is rare.
Japan and South Korea — tipping is uncommon and can be considered rude in some contexts.
Australia and New Zealand — tipping is optional; 10% for excellent service is appreciated but not standard.

How to Calculate a Tip Without a Calculator#

The easiest mental arithmetic method for calculating tips uses 10% as a base:

Find 10% of the bill by moving the decimal point one place left. £74 → £7.40
For a 20% tip, double that figure: £7.40 × 2 = £14.80
For a 15% tip, add half of the 10% figure: £7.40 + £3.70 = £11.10
For a 12.5% tip, add a quarter: £7.40 + £1.85 = £9.25

This method gets you within rounding accuracy for any tip percentage that is a multiple or fraction of 10. It's fast enough to calculate at the table without reaching for your phone.

Pre-Tax vs Post-Tax: Which Amount Should You Tip On?#

In countries where sales tax is added at the point of sale rather than included in the displayed price (notably the US), there is an ongoing debate about whether to tip on the pre-tax or post-tax total. The difference is small in practice — on a £60 pre-tax bill with 10% tax, a 20% tip differs by just £1.20 between the two approaches.

The most common practice in the US is to tip on the pre-tax amount, since the server did not provide the tax — they provided the service. However, many people find it simpler to tip on the total shown on the bill, and the financial difference is minor. Outside the US, where prices are typically displayed inclusive of tax, the question doesn't arise.

Splitting a Bill When People Ordered Different Amounts#

Equal splitting is simple but can cause friction when one person had a starter, main, and dessert with wine while another had a salad and water. A few approaches:

Item-by-item — each person pays for exactly what they ordered plus a proportional share of any shared items. Most accurate but requires itemising the bill, which takes time.
Proportional split — calculate each person's subtotal, then divide the total bill in the same proportions. Fairer than equal splitting for big spending differences.
Equal split with adjustments — start from an equal share, then adjust up or down for obvious outliers (e.g. the one person who had an expensive bottle of wine).
Whoever ordered more picks up the tip — a social convention in some groups where the bigger spender covers the tip as a trade-off for the simplicity of an even split on food.

Rounding Up vs Exact Splits: What's Simpler?#

Per-person amounts rarely divide to a round number. A total of £103.50 between 6 people is £17.25 each — fine for card payments but awkward in cash. Two common approaches:

Round up to the nearest £1 or £5 — each person pays £18, and the £4.50 surplus goes to the server as additional tip. Quick, generous, and eliminates change-making.
Exact split — each person pays precisely their share. Best handled digitally via card payments or a payment app rather than cash.

For cash situations, rounding up is almost always the easier option. For card splits at the table, most payment terminals in the UK and Europe now support split payment natively, making exact splits much simpler than they used to be.

Using the Free Tip Calculator#

The tip calculator at allio.tools takes three inputs: the total bill amount, the tip percentage you want to leave, and the number of people splitting the bill. It immediately shows you:

The tip amount in currency
The grand total (bill + tip)
The per-person share of the total

You can adjust the tip percentage with preset buttons (10%, 15%, 18%, 20%, 25%) or type a custom percentage. There is no sign-up or installation required — it works in any browser on any device. Useful for restaurants, taxis, hotel services, delivery orders, and any other tipping situation where you want to check the maths quickly and fairly.