/

True division: 7 / 2 is 3.5, and even 8 / 2 is 4.0 — floats, always.

Arithmetic operatorPython 3.0+Live demo
Common call
7 / 2
Returns
float, even for evenly-dividing ints
Replaces
integer division is // — a different operator
Watch out
division by zero raises ZeroDivisionError
aa — Dividend.type: number · required / bb — Divisor — zero raises.type: number · required
→ float

Demo

Live evaluation
Try:
Inputs
afloatdividend
bfloatdivisor
Output
7 / 2
3.5

The result is a true quotient — 7 / 2 gives 3.5, no truncation. (Python would print the evenly-divided case as 4.0 to mark it as a float; the demo shows the numeric value.) Dividing by zero raises Python’s exact error.

Operands

NameTypeRequiredDescription
anumberyesDividend.
bnumberyesDivisor — zero raises.

Return value

float — The quotient as a float — ALWAYS, even when both operands are ints and divide evenly.

Common patterns

Averages
The float result is what you want for means.
mean = sum(xs) / len(xs)
Guarded division
Handle the zero case explicitly when the divisor is data.
rate = hits / total if total else 0.0

Examples

1. True quotient
7 / 2
Returns
3.5
2. Even division is still float
8 / 2
Returns
4.0
3. Ints promote
1 / 3
Returns
0.3333333333333333

Pitfalls

1. Expecting an int result
Python 3 / never truncates — that is //.
Float where int expected
index = total / 2
items[index]
TypeError: list indices must be integers
Fix
index = total // 2
int index
2. Division by zero raises
Not infinity, not NaN — an exception.
Raises
1 / 0
ZeroDivisionError: division by zero
Guard
x / y if y else float("inf")
explicit choice

When to use

Use it
  • Any division where the fractional part matters
  • Averages, rates, ratios
Reach for something else
  • Whole-number division → //
  • Quotient AND remainder → divmod()
  • Exact decimal division → decimal.Decimal

Notes

Complexity
O(1)
Return
float (int/int included)
CPython impl
Objects/abstract.c :: PyNumber_TrueDivide → __truediv__
Memory
No allocation beyond the result
Thread-safe
Yes — pure computation

FAQ

Python 3 made / always produce a float so the result type never depends on the values. Truncating division is a separate operator, //.

History

3.0
int / int now returns float — the true-division switch (PEP 238).