Chapter 3 of 9 · 4 min read

An Intuitive Way of Looking at Volatility

How to translate a statistical volatility percentage into a practical, everyday expectation of how much an investment's returns can swing year over year.

By Ashish Gupta, PhD · Visuals powered by the EasyCompare Go Engine

We have spent a fair bit of time looking at Volatility because it underlies so much of our understanding of Risk. It is a foundational measure of risk on Wall Street, yet in the mainstream investment world, it is often completely missed.

One major reason for this gap is that volatility is not readily computed by most investors in their heads. Which is a shame, because computers can calculate it effortlessly in milliseconds. This chapter gives you an intuitive mental model so that volatility never feels arcane, and instead becomes a standard part of your investing toolkit and everyday vocabulary.

Fluctuation Around the Average Return

Suppose an investment returns 5% on average per year. Does that mean it always returns exactly 5% every single year? Not necessarily. Some years it may return 3%, other years 7%, and so on, such that its average over time turns out to be 5%. This fluctuation around the average is Volatility.

As a rough mental model, if an investment returns 5% in a typical year, a 40% relative variation around that average means that in one year it may return 3% (2 percentage points below 5%) and in another year 7% (2 percentage points above 5%). Note that this is an approximate guide: in reality, returns in any single year can go beyond this typical band in either direction.

Diagram illustrating how volatility represents the likely year-to-year swing around an investment's average annual return — **Figure 3.1: Volatility as the Year-to-Year Return Swing Around the Average.** Left: A steady investment averaging +5% per year with a modest ±2% variation band (40% of its 5% average) typically lands between +3% and +7%. Right: An asset with ~80% annual volatility (such as Bitcoin) can swing by ±80% year over year. Remember that this is a highly likely range, and actual returns in extreme years can vary even further.

What "X% Volatility" Means in Practice

So when we say an investment's annualized volatility is X%, an intuitive way of taking that information is that its return per year can vary by roughly X% from its normal or average return year over year.

For example, Bitcoin has shown a long-term annualized volatility of around 70% to 80% when measured over 5-year windows (77.0% in our 2018 edition and 69.4% in the 2020 to 2025 snapshot). This means its year-to-year returns can easily swing by 70% to 80%! That statistical reality was borne out directly in real market history: in late 2018, and again in 2022, Bitcoin's market value literally crashed by roughly 75% to 80% from its highs.

Using Volatility to Make Better Allocation Decisions

Volatility is most useful when comparing different investments against each other. It helps you decide whether to allocate less capital to a more volatile asset depending on how wide the risk gap is. A Risk-Balanced Approach (one that is governed by balanced returns rather than greed) calls for sizing your positions based on their measured risk. Volatility is not a perfect measure of every risk (as we will see in Part B when we examine Crash and Tail Risk), but it is an essential first metric to check on every investment. It can help you discover lower-volatility investments, or size your money more responsibly when you have already decided what you want to own.