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.

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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 math behind investing? ›

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 formula 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 mathematical approach to investing? ›

Quantitative investing uses mathematical models and algorithms to determine investment opportunities. Quantitative investment strategies include statistical arbitrage, factor investing, risk parity, machine learning techniques, and artificial intelligence approaches.

Am I on track for retirement for my age? ›

By age 50, you would be considered on track if you have three-and-a-half to six times your preretirement gross income saved. And by age 60, you should have six to 11 times your salary saved in order to be considered on track for retirement.

What is the 4 rule in investing? ›

The 4% rule entails withdrawing up to 4% of your retirement in the first year, and subsequently withdrawing based on inflation. Some risks of the 4% rule include whims of the market, life expectancy, and changing tax rates. The rule may not hold up today, and other withdrawal strategies may work better for your needs.

What is the rule #1 of value investing? ›

The Rule One view of value investing dictates that the best way to make large returns on your investments is to find a few intrinsically wonderful companies run by good people and priced much lower than their actual value.

What is the formula for financial success? ›

Knowledge + Time + Behavior = Financial Success*

However, we believe following this formula tends to have a profoundly positive impact on your financial outcome.

What formulas do financial advisors use? ›

Here are some common formulas professionals in the finance industry use:
  • Compound interest. ...
  • Post-tax return. ...
  • Inflation. ...
  • Liquidity ratio. ...
  • Risk premium. ...
  • Working capital. ...
  • Return on Assets (ROA) ...
  • Marginal cost.
Dec 22, 2022

Is there an algorithm for investing? ›

Algorithmic Trading Types

They range from simple single-stock to more complex black-box algorithms that analyze market conditions, price moves, and other financial data to execute trades at optimal times for the least cost-to-maximum profit ratio.

Do I need to know math to invest? ›

Do I need to be good at math to invest in the stock markets? It is not necessary to be good at math to invest in the stock markets, however, basic math can help an investor identify good stocks and know how much returns they can expect from the same.

What are the mathematical methods to predict stock prices? ›

The P/E multiple or price/earnings ratio compares the closing price of the stock with the earnings of the last 12 months. A high value is often a reflection of lofty expectations of stock price and may indicate that the stock is overpriced.

What is the $1000 a month rule for retirement? ›

One example is the $1,000/month rule. Created by Wes Moss, a Certified Financial Planner, this strategy helps individuals visualize how much savings they should have in retirement. According to Moss, you should plan to have $240,000 saved for every $1,000 of disposable income in retirement.

Can I retire at 60 with 300k? ›

£300k in a pension isn't a huge amount to retire on at the fairly young age of 60, but it's possible for certain lifestyles depending on how your pension fund performs while you're retired and how much you need to live on.

What is the mathematical modeling approach? ›

Mathematical modeling approaches can be categorized into four broad approaches: Empirical models, simulation models, deterministic models, and stochastic models. The first three models can very much be integrated in teaching high school mathematics. The last will need a little stretching.

Which mathematical concept is used in stock market? ›

Probabilities are a very helpful concept in math for stock market. Probabilities can help an investor can get an idea of what the odds are of an investment performing well.

What is the definition of mathematical approach? ›

A mathematical approach refers to the use of mathematical principles and calculations to understand and explain natural phenomena, including in the field of astronomy. It involves applying quantitative methods to gather data, make predictions, and test hypotheses.

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