ZeroDivisionError: division by zero

You’re dividing a number by zero, which is mathematically undefined.

Fix 1: Check before dividing

# ❌ Crashes if total is 0
average = sum_values / total

# ✅ Check first
if total != 0:
    average = sum_values / total
else:
    average = 0

Fix 2: Use a default with try/except

try:
    result = a / b
except ZeroDivisionError:
    result = 0  # or float('inf'), or None

Fix 3: Common scenarios that cause it

Empty list average:

numbers = []

# ❌ len([]) is 0
average = sum(numbers) / len(numbers)

# ✅ Check for empty
average = sum(numbers) / len(numbers) if numbers else 0

Percentage calculation:

# ❌ total_users could be 0
percentage = (active_users / total_users) * 100

# ✅ Guard against zero
percentage = (active_users / total_users) * 100 if total_users else 0

Modulo operator too:

# ❌ Also raises ZeroDivisionError
result = 10 % 0

# ✅ Check first
result = 10 % divisor if divisor != 0 else 0

Related resources

• Python cheat sheet
• Python complete guide