Skip to content

Lottery odds calculator

Math & numbers

How likely is it to win the lottery?

The number of possible rows in a lottery draw and the chance that one row hits the jackpot.

Jackpot chance per row

1 in 18,643,560

A draw of 7 numbers out of 40 has 18,643,560 possible rows, and only one of them hits the jackpot.

More about the count

Formula
C(40, 7) = 40! ÷ (7! × 33!)
Possible rows
18,643,560

Sponsored Links

The number of possible rows in a lottery draw and the chance that one row hits the jackpot.

How to use

  1. Enter how many numbers are in the draw and how many you pick on one row, such as 7 out of 40.
  2. Read the chance that one row hits the jackpot, with the number of possible rows.
  3. For a game with two drums, count each drum on its own and multiply the rows.

Sponsored Links

How it works

A lottery row wins the jackpot only if it matches every drawn number. The order of the draw does not matter and a ball never comes back, so the number of possible rows is the number of combinations: C(n, k) = n! ÷ (k! × (n − k)!), with n the numbers in the draw and k the numbers on a row.

Drawing 7 numbers out of 40 gives 40! ÷ (7! × 33!) = 18,643,560 rows, so one row has a 1 in 18,643,560 chance. Ten rows have ten times the chance, still 1 in 1,864,356.

The odds hold for a fair draw, where every row is equally likely. Smaller prizes for fewer correct numbers have their own, better odds, and a shared jackpot is split between the winners.

Worked example

How many pairs can you choose from 5 distinct items without repeats?

  1. There are 20 ordered picks, but each pair appears in 2 orders.

Ignoring order gives 20 ÷ 2 = 10 pairs.

Frequently asked questions

What are the odds of a lottery that draws 7 numbers out of 40?

There are C(40, 7) = 18,643,560 possible rows, so one row has a 1 in 18,643,560 chance of hitting all seven.

How do I work out the odds of a game with two drums?

Count each drum on its own and multiply. Picking 5 of 50 and then 2 of 12 gives 2,118,760 × 66 = 139,838,160 possible rows.

Do some numbers win more often?

No. In a fair draw every row is equally likely, so no pattern or past result changes the odds.

Sponsored Links

Sponsored Links