NZ's most common birthday revealed

Those who were born on September 30 may or may not be happy to know they share their 'special' day with about 14,000 other Kiwis. Photo / iStock

Kiwis wallets are in for a "hammering" this month, with Statistics New Zealand warning that 180,000 New Zealanders will celebrate - or not celebrate - their day of birth.

And those who were born on September 30 may or may not be happy to know they share their 'special' day with about 14,000 other Kiwis.

"Peak birthday" period begins on Saturday and in the 13 days between September 19 and October 1 the 10 most popular birthdays will occur, Statistics New Zealand senior demographer Kim Dunstan said.

At the other end of the spectrum, the least common birthdays tend to be around fixed public holidays like Christmas Day, she said.

After February 29, the least common birthdays in New Zealand are between December 24 and 27, January 1 and 2, Waitangi Day and Anzac Day.

Peak birthday period in New Zealand is similar to that in the US but the pattern is less extreme in Australia and the UK, Mr Dunstan said.

Each year, New Zealanders spend more than $322 million on games, toys and hobbies.

To help Kiwis manage their gift-giving budget, Statistics NZ has released Rank your birthday, a tool to show birthdate rank, how common it is, and how many people potentially share the big day.

The calculator is based on births from 1980 to 2014.

Days are ranked one to 366 by number of births - one is the most common birthday and 366 the least common.

Some days are tied for ranking because they have the same number of births.

But there is some good news for New Zealanders' bank balances when looking for a potential gift, according to Statistics NZ.

"While prices this year are up 1.7 percent from last year, they're still down 13 percent from five years ago. So a toy or game that cost $30 in 2010 is now only $26."