💸 Build a Tip Calculator

What You'll Build

A function that takes a bill amount and a tip percentage and returns the tip and the total. Then we wrap it in an interactive prompt.

Step 1 — the Core Function

function calcTip(bill, percent) {
  const tip = bill * (percent / 100);
  const total = bill + tip;
  return { tip, total };
}

console.log(calcTip(50, 18));
// { tip: 9, total: 59 }

def calc_tip(bill, percent):
    tip = bill * (percent / 100)
    total = bill + tip
    return { "tip": tip, "total": total }

print(calc_tip(50, 18))

Step 2 — Round Nicely

Currency should usually be 2 decimal places.

function calcTip(bill, percent) {
  const tip = +(bill * percent / 100).toFixed(2);
  const total = +(bill + tip).toFixed(2);
  return { tip, total };
}

Step 3 — Split the Bill

function splitBill(bill, percent, people) {
  const { total } = calcTip(bill, percent);
  return +(total / people).toFixed(2);
}

splitBill(50, 18, 4); // 14.75

Stretch Goals

• Add a button on a webpage that runs the calculator on form input.
• Validate input — reject negative bills, zero people.
• Round up the per-person amount so the actual tip is at least the requested %.

Concepts You Just Used