Kate does some simple maths before she spends $20 on the cheap and nasty ready-to-drink alcohol that gets her drunk fast.
It's a Thursday night and central Hamilton is fast filling with revellers spilling out of taxi vans into the bars and clubs that were near-empty just an hour earlier.
The tipsy 19-year-old's hair is unkempt and she's barefoot with a jersey pulled over what looks like a pair of leotards.
She's on the lash with a couple of mates having just broken up with her boyfriend and by her own accounts has downed about 10 "Volts" and "Tattoos" - RTDs that cost less than $20 for a dozen.
The McDonald's worker says she carefully measures the alcohol percentage of her drinks before she makes her buy for the night.
"No one buys 5 per cent or under any more because it doesn't get you f****d up," she says.
"You can pay $22 and get 12 of 5 per cent or $20 and get 12 of 8 per cent. They're easy to drink because you can't taste the alcohol and they get you drunk."
Kate and her friends, one a 20-year-old mother, and another who runs at the sight of the Herald photographer, have been "on the piss" for the past six hours.
The group are among a growing number of young women identified in a recent survey by Massey University's Social and Health Outcomes Research and Evaluation (Shore) public health unit that has found the numbers of girls having at least eight drinks at a sitting almost doubled since a previous survey in 2004 in the 16-17 and 18-19 age groups.
Shore director Professor Sally Casswell said the increase up to 2004 followed the arrival of ready-to-drink (RTD) "alcopops" in 1995 and the lowering of the drinking age from 20 to 18 in 1999.
When told their efforts probably qualify them as binge-drinkers Kate lets out a celebratory "f*****g woop!"
"If you buy a box you're going to drink the whole thing, aren't you ? It'd be pretty stupid if you didn't."
Not long after, the Herald bumps into two more young women, Mia and Chanelle, both beautiful, well made-up, fragrant and armed with their passports to get into the clubs for Chanelle's 18th birthday.
The pair talk excitedly and bat their eyelids furiously having spent the past five hours drinking a $35 one-litre bottle of vodka that contains 40 per cent alcohol.
"A higher percentage gets you drunker faster, I'll admit that," says 19-year-old Mia.
Both began drinking alcohol at a young age, Chanelle was 14 and Mia 15, when they got their booze from their mates.
They've had more than the ALAC definition of binge-drinking - seven standard drinks in an evening - high-fiving each other when they hear this before quickly denying they have a drinking problem.
"It's just to have fun, I like to drink but I hate it when you lose control and I hate spewing, I stop when I feel sick," says Chanelle.
When asked why they drink so hard, Mia replies: "I'm not going to lie but this generation is disgusting."
"I reckon it's because of things like Geordie Shore, you know they're crazy and you think 'oh my god, I want to be crazy like them'."
Hamilton doorman Josh Wirepa-Kio has been bouncing outside of pubs for the past six years including a stint in Australia at bars in Brisbane and on the Gold Coast, where he says binge-drinking among young women is "much worse".
"People earn more ... the booze is cheaper and they spend more when they go into town. But things are getting pretty bad here too."
Mr Wirepa-Kio says there has been a noticeable change with younger women pre-loading before they come into town for their night out.
He thinks the cost of alcohol at bars could be a factor making people drink more at home.
"I remember when people used to come into town a few years back semi-sober but now they arrive completely chopped."
"Give them half an hour and they're finished, they usually end up arguing or fighting, I saw three girls fight over one guy once, that was funny."