How to calculate tips:

When calculating the tipping amount, you need to decide the percentage of your bill to tip based on the quality of the service. For example, you think the service you are having today is fabulous, you can think of 20% of your bill. Otherwise, if you think the service is normal, you can choose 10% or 5% but there is a rule of thumb to choose tipping percentage between 10%-20% so bear this in mind.

Shared Bill Tip Calculator 

The Shared Bill Tip Calculator considers the cost of the service, number of people, and chosen tip percentage to calculate the tip per person, as well as the total cost per person.

A tip or gratuity is an extra sum of money paid to certain service workers for a provided service. Tip amounts, as well as acceptance, vary in different parts of the world. In some countries in East Asia, such as Japan, tips are seen as insulting and can sometimes be interpreted as a bribe. In yet other countries, such as the United States, tipping is widely expected, and in many cases, is even factored into a service worker's compensation towards satisfying the minimum wage requirement. This is important to note, since although tipping is entirely voluntary, many servers depend on tips to make a living in countries like the United States. As such, as a tourist, it can be helpful to research the tipping customs in the countries being visited. In the U.S. or any other country where tipping is expected, depending on the restaurant or the number of patrons at a table, gratuity may be automatically applied to the bill amount. As previously mentioned, tipping can be offensive in some countries, so although a citizen of the United States that is visiting another country may want to express their appreciation of the service provided, the gesture may, in some cases, result in the opposite effect.

To save time, you could use conversion online tools:

https://www.calculatorful.com/tip