Figuring out how much to gift a newlywed couple can be a hard decision. Photo / Getty Images

I stood at the 7 Eleven ATM in a pair of chunky white high heels and a flowing white bridesmaids dress in a cold sweat.

It was Aisha and John's wedding day — and I had absolutely no idea how much money to put in their wishing well.

I thought my biggest concern of the day was the Fanta orange spray tan that had been applied to me by the trigger-happy beautician the day before.

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Calculating how much to spend on a wedding gift takes the brain of Stephen Hawking, the heart of Oprah and the strategy of whoever won Donald Trump the election.

Too much and you can't afford life's essentials (like Tinder Premium). Too little and you risk being a social pariah and dying alone.

I asked the question of how much to spend on a wishing well gift to the Facebook community 'Bad Dates of Melbourne' and it seems everyone has a different opinion.

"Apparently you are supposed to do it according to how much they paid by head and divide it by two," said one person.

"So, if they paid $10 per head. You get a $5 gift? Two meat pies it is!", someone replied.

Clearly there is no consensus on this controversial topic or on how much weddings cost.

(Note: there is consensus however on how delicious meat pies are. They are very delicious.)

So, let me get down on one knee and make a proposal to you. A simple universal formula to ascertain once and for all how much you should spend on a wishing well gift at a wedding.

The Formula

Step 1. Take your salary before the last comma: e.g. if you earn $50,000 — your starting number is 50.

Step 2. Add $5 for every year you have known the couple. Hopefully this has been a short friendship.

Step 3. Minus $20 if they didn't write on your Facebook wall for your birthday.

Step 4. Is it a destination wedding? Uh oh. Minus the cost of a new bikini.

Step 5. Are you planning on making an embarrassing wedding speech? Humiliation can be absolved with a cool pineapple ($50 note).

Step 6. Is it a sit down meal or finger food? A well planned wedding gift budget will allow for the Quarter Pounder you will inevitably consume on the way home from the reception.

Step 8. Did the bride and groom attend your wedding? Try and remember what amount they gave you so you can beat it by a few dollars.

Step 9. Are you single and alone? Luckily, people have low expectations of you and the contribution you make to society, which is fantastic as you can take off $20.

Step 10. Is the family member a relative? This doesn't affect your calculation but you should remember your grandma will be there. Keep it together for your Nanna.

Congratulations! Now you know how much to give to a wedding wishing well.

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As for me, I don't remember how much money I gave Aisha and John. They are happily married now with two beautiful children and a lifetime of love and joy ahead of them.

But really ... how much to give at a wedding? Give what you can afford. The real gift lies in everyday moments like picking up the phone to say hello, doing last minute babysitting or having a quick latte.

Just don't forget the card, have fun and remember — you look great without the spray tan.