The "magic math" behind consistent investing (2024)

Investing consistently is a key building block of wealth building, but many people don’t understand why it is so powerful. Well, today we’re going to explain it to you! And once you understand it, you’ll be even more motivated to keep your investing consistent.

The "magic math" behind consistent investing (1)

First, make sure you have your emergency fund in place, and focus on becoming debt-free. Because hey, knocking out a 10% interest rate is similar to gaining 10% on an investment – so do this first. Then take a look at your household budget to see how much monthly cash you can allocate toward investing.

Whatever this amount is, lock it in, put it on the budget, and invest that exact amount every single month. Do this regardless of what the market is doing or what the talking heads on TV are saying. Be like Nike and Just Do It.

Here’s how much do YOU need to invest, from any age, to become a millionaire. Even if you don’t have the exact amount you need monthly right now, get started. Start where you can right now and increase it over time. That’s absolutely fine and a great way to start your millionaire plan!

Again, set an amount and stick with it. Invest when the market is going strong, and when the market is tanking. Invest consistently.

Not familiar with how to invest? Reach out to an unbiased financial life planner who can help you understand how investing might fit into a plan for achieving your goals.

By the way, this principle has a name:

Dollar-Cost Averaging

Dollar-cost averaging, or DCA, is the practice of investing a fixed dollar amount on consistent intervals (typically this ismonthly) in spiteof what is going on with the stock market.

While this is “simple”, it isn’t quite easy to implement in practice.

The reason is that investing, like most financial matters, is just as much about emotion and behavior as it is about math. Sending a check to your investment company when the market is in a free-fall is emotionally challenging. Our emotions tell us to hold back and wait until the “right time” to make the investment. Of course, study after study has confirmed that most people, including investment advisors, are horrible at timing the market and this costs investors millions of dollars in missed gains.

The trouble with trying to “time the market”

I talk to many people who think it just isn’t the right time to make an investment deposit right now – for any one of dozens of reasons. Oil prices, the value of the US dollar, the economy in China, wage levels, etc, etc. Since drama draws viewers, the people reporting the news are likely to focus on whichever unpredictable variable is most popular at the moment.

So what many people end up doing is holding on to the cash that should be invested (or worse-case they spend it instead of holding it) and they wait for the perfect opportunity to invest.

The problem is: when is that perfect opportunity?

If the market is in a downtrend right now, do you wait for it to start going back up again? If so, how much? Maybe wait for it to rise 5% before putting in your money, but who is to say it won’t trend back down again even further than the recent rise? Or what if it doesn’t trend back down, but since you waited you missed out on a 5% gain in this example.

RELATED BOOK: The Automatic Millionaire

The point is there is no perfect time

Have you heard of Warren Buffett? I’m guessing you have. He made a $1 million dollar bet that a buy-and-hold strategy in an S&P 500 index fund would beat the returns on five actively managed funds (aka market timed and industry-shifted investments) over a ten year period. Eight years into the bet Buffett’s S&P fund had about three times the returns of the actively managed funds.

Market timing isn’t working out very well even for these top-notch investment managers who do this every day for a living. So then why do so many people think they can do better? Maybe because they don’t understand the magic math of consistent investing.

Consistent investing – dollar cost average investing – is exactly how slow and steady got me to a half-million in my retirement account in my early 40s. Together with my wife’s retirement account, we’ve passed the million-dollar mark. This really works.

TheMagic

Let’s look at a fictional stock – we’ll call it MYM – as a way to illustrate the power and magic of dollar-cost average investing. In this example, we have $500 per month budgeted for investing and we will follow the DCA principles and invest that amount on the 15th of each month, regardless of what the stock price is doing.

So here is how the investing looks over a fictional six month period:

MonthAmount InvestedMYM Share PriceShares Purchased
Month 1$500$756.67
Month 2$500$1005
Month 3$500$5010
Month 4$500$806.25
Month 5$500$1254
Month 6$500$1005
Total InvestedAverage PriceTotal Shares
$3,000$88.3336.93

This is fairly straight-forward but I’ll make sure one point is clear: Since we are investing the exact same dollar amount each month, the number of shares purchased changes each month due tothe stock price changes. What that means is when the price is lower, you purchase more shares and when the price is higher, you purchasefewershares.

So when the stock is discounted, you buy more; when it is priced at a premium you buy less – all without any thought or work required of the investor. It just happens automatically.

RELATED BOOK: The Behavior Gap: Simple Ways To Stop Doing Dumb Things With Money

That is pretty powerful when you think about it. Here is something else to think about: your average purchase price is lower than the stock’s average price.

Yeah, really. You can see that the average stock price over the three months is $88.33 above, but since you bought more at a discount and fewer shares at a premium, your personal average cost per share is only $81.23($3,000 invested into 36.93 shares).

That sounds to me a lot like “beating the market”, but without even trying.

Side note: If you had invested $500/month into the S&P 500 index over the past 30 years, you’d have about half a million today.

Market fluctuations – volatility – is your DCA friend

Whenyou are still in the wealth-building phase of life, and following the dollar-cost averaging principle, then market fluctuations are a very good thing!

Market fluctuations – aka “volatility” – are a normal part of market cycles. Stocks go up, and they go down, then up, then down. In fact, there tends to be a market correction (a drop of at least 10%) every few years – even though the long-term average is around a positive 10% annual gain. These fluctuations are normal and an expected part of investing, and when you practiceDCA investing, that’s good for you!

If the market happens to be down 10%, 20%, or even more – that means you are buying your stocks at discount fire-sale prices!

Far too many people see this and panic then stop their investing, but that is absolutely the wrong way to look at this. You need to look at it as part of your overall long-term strategy and understand that price fluctuations, and even corrections and “bear markets” (declines of 20% or more) are normal and okay.

RELATED POST:Understanding Investing Risk and Your Risk Tolerance

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The amount doesn’t matter as much as just doing it

Of course the more you can invest, the faster you will be able to grow your wealth through investing. But understand that something is better than nothing. Even if you can only afford $50/month this year – do it, then workto increase the amountover time.

Time is your friend when investing. It is a marathon and not a sprint. So the sooner you start investing and the longer your time horizon, the more growth potential your investment account will have.

In Closing

Hopefully, this helped clarify the power of consistent monthly investing for you. If you haven’t already, it’s time to develop a personal investment plan that uses dollar-cost averaging to maximize your returns; and to avoid the many challenges of trying to time the market.

As a fee-only financial advisor, I can help you clarify your dreams and priorities, then develop an actionable plan to achieve your goals. Having a financial plan for your life includes much more than just investing, but intelligent investing is definitely part of the solution. Just select Start Here and let’s talk about how I can help you maximize your money to achieve the life of your dreams.

Do you use dollar cost averaging already? If not, do you have any questions about it? Let us know in the comments below.

The "magic math" behind consistent investing (2024)

FAQs

What is the Magic Formula of investing? ›

Magic formula investing uses a set of quantitative screens to eliminate certain companies, and ranks the remainder in order of highest yield and returns. By slowly building and rebalancing the portfolio every year, it is possible to achieve reasonably high returns.

What is the math behind investing? ›

If you want to know what percentage return you've made on your investment, divide your profit by the price you paid for the stock and multiply by 100. That's division and multiplication. Arithmetic is the foundation of all the calculations you'll do as an investor.

What is the math behind DCA? ›

The calculation for dollar-cost averaging works the same as calculating the average or mean for a set of numbers. In the case of DCA, the investor adds investment purchase prices, then divides the sum by the amount of purchases made.

What is the math equation for investment? ›

The amount of interest earned on an investment or due on a loan is calculated using I = Prt. This formula can also be used to determine: the amount of principal (P) that needs to be invested in order to earn a certain amount of interest over a certain period of time.

What is the 70% rule investing? ›

Basically, the rule says real estate investors should pay no more than 70% of a property's after-repair value (ARV) minus the cost of the repairs necessary to renovate the home. The ARV of a property is the amount a home could sell for after flippers renovate it.

What is the 5% rule in investing? ›

The 5% rule says as an investor, you should not invest more than 5% of your total portfolio in any one option alone. This simple technique will ensure you have a balanced portfolio.

What is the rule #1 of value investing? ›

Value investors often make decisions similar to what Ben Graham did, based on the business looking cheap, but Rule One investors know that it is better to buy a wonderful business at a fair price than a fair business at a wonderful price.

What is the 1 rule of investing? ›

Warren Buffett once said, “The first rule of an investment is don't lose [money].

What is the 4 rule in investing? ›

The 4% rule limits annual withdrawals from your retirement accounts to 4% of the total balance in your first year of retirement. That means if you retire with $1 million saved, you'd take out $40,000. According to the rule, this amount is safe enough that you won't risk running out of money during a 30-year retirement.

Does DCA actually work? ›

Dollar-Cost Averaging

DCA is a good strategy for investors with lower risk tolerance. Investors who put a lump sum of money into the market at once, run the risk of buying at a peak, which can be unsettling if prices fall. The potential for this price drop is called a timing risk.

How to DCA correctly? ›

When dollar-cost averaging, you invest the same amount at regular intervals and by doing so, hopefully lower your average purchase price. You will already be in the market when prices drop and when they rise. For instance, you'll have exposure to dips when they happen and don't have to try to time them.

What is the DCA strategy? ›

How Does Dollar Cost Averaging Work? The dollar cost averaging (DCA) strategy is when investors invest their funds in set increments, as opposed to putting all the capital on hand to use immediately.

What is the math behind investments? ›

To calculate the annual rate of return for an investment, you need to know the income created, the gain (loss) in value, and the original value at the beginning of the year. The percentage return is calculated as: Return = 100 x (Income + Current Value – Original Value)/Original Value.

What is the math behind the stock market? ›

Assessment and management of risks are key parts of the basic math involved in the stock market. Their formulas include standard deviation (SD), value at risk (VaR), R-squared, Sharpe ratio, and conditional value at risk (CVaR). Before investing, investors should also calculate the risk-to-return ratio.

What is the real investment equation? ›

For an investment, a real interest rate is calculated as the difference between the nominal interest rate and the inflation rate: Real interest rate = nominal interest rate - rate of inflation (expected or actual).

What is the famous investment formula? ›

To calculate the number of years required to double the investment at a given rate of return, you need to divide 72 by the rate of return. So, if an investment offers a 9% return, you need to invest for 72/9 = 8 years to see your money double.

What is the rule number 1 in investing? ›

Warren Buffett once said, “The first rule of an investment is don't lose [money]. And the second rule of an investment is don't forget the first rule.

What is the magic formula investing ratio? ›

This is how the two Magic Formula investing ratios are calculated: Return on invested capital (ROIC) = EBIT / (net working capital + net fixed assets). Earnings yield = EBIT / Enterprise value.

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