Planning a wedding? It could cost you $1.3 million.

The average wedding in Australia costs $35,000. This may seem like a lot of money to spend on one day, which it is, but the potential cost over the long term is so much more.

In fact, your wedding day could actually see you retire $1.3 million poorer. And that's just with an average wedding.

So, how can your wedding possibly cost this much money? The answer is simple: by missing the opportunity to invest while you're young.

An average $35,000 wedding could cost you more than $1 million by retirement.

By the time you add up the dresses and suits, the photographer, celebrant or church fees, the band, the venue and catering as well as incidental costs like travelling and accommodation, it's easy to see how an average wedding can add up to $35,000.

But what would that $35,000 add up to later on if you invested it in the share market or your super fund? Quite a lot, according to Stockspot's head of advice Sarah King.

"That $35,000 invested into an Australian share index fund, would grow to around $779,800 in 30 years and $2,194,000 in 40 years. This is based on the historical average return from the Australian share market of 10.9% p.a."

"Personally, I think it's a really wise choice," said King.

"Rather than using the majority of your savings, or even getting into debt, to fund a bigger wedding, a smaller, intimate wedding helps keep costs down and allows you to balance both short-term and long-term goals. Short term, being a beautiful intimate wedding (that's over in 24 hours), with long term, an investment portfolio that's growing and can be used to fund a future goal for you both, like a home deposit.

"That's exactly what my husband and I did. After the first major COVID lockdown, we canned our Bali wedding, opting for a super intimate Sydney wedding with just 8 of us. By keeping it small, we continued investing to save for our home deposit and didn't have to dip too much into our savings. In hindsight, it was the best decision for us as a couple, with house prices soaring ahead here in Sydney. And our wedding was still amazing!"

Laura and Sarah recently opted for a backyard wedding at Sarah's parents' house in Adelaide with 34 of their closest family and friends. The entire wedding cost $10,393.

Sarah said avoiding traditional wedding vendors as much as possible helped them drastically cut down on the cost.

"The cake was through a friend of a friend and was $150 for ingredients. I found my dress on Facebook for $99, and Laura found hers for $300. Instead of going for a normal wedding caterer, we found a husband and wife team from Kuala Lumpur and they put on a Malaysian feast for us. The photographer was the only thing we didn't cut back on. Out of everything on the day, we thought it'd be nice to capture it in a great way.

"The day was perfect. it was everything I wanted it to be. Having a small number of people meant we could spend time with everyone. We didn't feel like we were rushing and we also got to spend time together. It was just a really relaxing day."

Sarah and Laura's main motivation for having a small wedding was their goal of retiring early. Thanks to their frugal lifestyle and regular investments from an early age, the pair are on their way to being able to retire within the next 5 years.

"We are very much focused on saving and are currently on the path to FIRE (financial independence retire early). So we really wanted to put as much money as possible into shares so we could start generating that passive income and building that up as early as possible. We mainly invested the money saved from having a small wedding in a mix of Vanguard index funds," said Sarah.

"We have friends who have spent $80,000 or $100,000 as they decided they wanted a wedding instead of a house deposit, or they wanted a wedding instead of starting a share portfolio. For me, I can't understand that. It's just way too much money down the drain."

James and Erin were married in London in 2019 surrounded by 30 of their closest family and friends. The ceremony was held at a beautiful, old town hall in the city and the reception was dinner and drinks at a Scandinavian pub nearby. The entire ceremony and reception cost just £3,500, which is around AUD$7,000 – significantly less than the $35,000 average cost.

"We hired a wedding photographer who was in the early stages of his career and looking to build up his portfolio. He was fantastic, and the cost was significantly less than if we'd gone for a wedding photographer with many years of experience."

James said he and Erin chose to have a more intimate wedding for financial reasons and doing so allowed them to achieve some pretty big goals.

"If we'd spent more money on the wedding, it would have been much harder to buy our home and taken a lot longer. And there could have been an expensive knock-on effect. Realistically, we would have needed to keep saving throughout 2021, while watching house prices skyrocket across NSW. We count ourselves very fortunate to have found a place in the last few months of 2020."

While James said they wouldn't change anything about their wedding day, he did acknowledge that a smaller wedding does come with some sacrifices too.

"Being of Irish heritage, having to keep the guest list small was not easy. We didn't invite any of my Ireland or UK-based cousins. My wife only invited her immediate family over to London from Sydney. I also had a few close friends who unfortunately didn't make the cut! This was the hardest part of our decision to scale back on the size of our wedding."

"The share market gets bumpy, so having defensive investments in the mix helps to smooth that out and cushion you on the downside, which you're always really thankful for when a share market dip comes."

If you're thinking of adding the money to your super fund, most Balanced, Growth and High-Growth super portfolios will automatically invest in a mix of different asset classes on your behalf to ensure your super is well diversified.

"I'd typically suggest drip-feeding smaller amounts, regularly into the market (known as dollar-cost averaging) over a few weeks or months because it removes the need to try and time the market, which we know is very difficult to get right. Instead, you average your way in gradually and get your money starting to work for you. Also if you're new to investing, it makes you feel that bit more comfortable getting started."

If you're investing in the share market, you can set up a regular transfer each month. Or if you're adding the savings into your super, you can achieve this easily by setting up a salary sacrifice arrangement where a small part of your pay is transferred to your super each payday.

But one of the biggest tips is to simply get started – don't delay.

"Starting to invest in your 20s compared to your 30s or 40s, will have a material impact on your investment balance in future years. If you're thinking about investing, start now. Time is of the essence with investing. Remember that money kept in savings over the long term is going backwards."