Dict Mini Project — Tip Calculator

What you're building

A tip calculator. The user enters the bill amount and rates the service. The program looks up the tip percentage from a dict and calculates how much to leave.

What you need to know first

• Dicts — creating and reading
• Square bracket lookup and get()
• in to check if a key exists
• input() and float()
• if / elif / else

The brief

Build a program that:

• Stores tip percentages in a dict: "poor" → 10%, "good" → 15%, "excellent" → 20%
• Asks the user for the bill amount
• Asks the user to rate the service: poor, good, or excellent
• Looks up the percentage in the dict
• Calculates and prints the tip amount and the total bill
• Handles an invalid rating gracefully

Think before you code

• What type should the bill amount be?
• How do you look up the rating in the dict safely?
• What do you do if the user types something that isn't a valid rating?
• How do you calculate the tip and the total from a percentage stored as a decimal?

Your starting point

tips = {
    "poor":      0.10,
    "good":      0.15,
    "excellent": 0.20
}

bill = float(input("Bill amount: $"))
rating = input("Service (poor / good / excellent): ").lower()

# your code here

Expected output

Bill amount: $85
Service (poor / good / excellent): good

Tip (15%):   $12.75
Total:       $97.75

Bill amount: $85
Service (poor / good / excellent): amazing

Invalid rating. Choose: poor, good, or excellent.

Heads up!

• Use .lower() on the input so "Good" and "GOOD" both work
• The percentage is stored as a decimal — 0.15 means 15%
• Use in to check if the rating is valid before looking it up
• Format the output with :.2f for two decimal places

The solution

tips = {
    "poor":      0.10,
    "good":      0.15,
    "excellent": 0.20
}

bill = float(input("Bill amount: $"))
rating = input("Service (poor / good / excellent): ").lower()

if rating in tips:
    percentage = tips[rating]
    tip = bill * percentage
    total = bill + tip
    print(f"\nTip ({int(percentage * 100)}%):   ${tip:.2f}")
    print(f"Total:       ${total:.2f}")
else:
    print("Invalid rating. Choose: poor, good, or excellent.")