When people think about retirement planning, the first thing that often comes to mind is investment returns.

They discuss where to invest to earn a certain percentage, whether stocks are better, or if real estate is the way to go.

However, what truly changes the size of your retirement fund is not just investments—it's taxes.

Even with the same amount of money invested, how you manage taxes can significantly affect the outcome. That's why in the U.S., the term that often comes up before investments in retirement planning is tax savings.

The most basic method is to properly utilize tax-advantaged retirement accounts.

The most common example is the 401(k). If you work for a company, you've probably heard of it at least once. The key feature of this account is that you invest with pre-tax income. For instance, if your annual salary is $80,000 and you contribute $10,000 to your 401(k), your tax calculation is based on $70,000, not $80,000. This structure reduces the taxes you pay immediately.

There's an even more interesting aspect: company matching. Some companies will contribute money when employees put in a certain amount. For example, if you contribute 5% of your salary, the company will also contribute 5%. In simple terms, it's like getting free money. That's why in the U.S., people often say, "Never miss out on company matching."

But it's not just 401(k)s. Individuals can also use IRAs.

A Traditional IRA is structured so that you pay taxes later. You can receive a tax deduction when you contribute now, and you don't pay taxes on the interest or earnings while investing. Instead, you pay taxes when you withdraw the money after retirement. The longer the investment period, the more significant the tax deferral effect.

Another frequently mentioned account is the Roth IRA. This account is funded with money that has already been taxed. While there are no tax benefits now, there are no taxes when you withdraw the money later. You can withdraw both the principal and investment earnings tax-free. Starting young and investing for a long time often makes this structure quite advantageous.

Another account that is surprisingly often mentioned in retirement planning is the HSA.

Originally a medical expense account, it is utilized for retirement planning due to its excellent tax benefits. Contributions to an HSA are tax-deductible, there are no taxes on investment earnings within the account, and there are no taxes when you withdraw for medical expenses. That's why in the U.S., it's referred to as a "triple tax benefit" account.

Some people also consider taxes when making investments. For example, they might place high-dividend assets in tax-advantaged accounts and long-term growth assets in regular accounts. The tax outcomes can vary depending on which accounts hold which assets, even with the same portfolio.

Another point to remember is long-term capital gains tax. In the U.S., if you hold an investment asset for more than a year, the long-term capital gains tax rate applies. This rate is lower than the regular income tax rate. Therefore, a strategy of holding investments for a longer period is often more favorable from a tax perspective than short-term trading.

There is also a strategy used right before retirement called Roth conversion. Simply put, it involves moving part of a Traditional account to a Roth account. You pay taxes once during this process, but you can withdraw funds tax-free afterward. Some people use this strategy during the early retirement phase when their income decreases.

Ultimately, preparing for retirement funds is not just about how much you earn. How you reduce taxes is also a significant variable.

Even if investment returns are slightly lower, effective tax management can lead to better outcomes. That's why in the U.S., when discussing retirement preparation, it's often said that while investments are important, understanding the tax structure first is what allows people to endure in the long run. In the end, preparing for retirement funds might not just be an investment game but a tax game as well.