Here's a small moment most of us have had. Someone says a friend is 6 feet tall, you picture it, and then you meet them and they look nothing like what you imagined. Numbers are a poor way to feel height. A height comparison chart fixes that by putting two or more people side by side, drawn to the exact same scale, so the difference is something you can see instead of something you have to calculate.
I built HeightComparison because I kept doing this math in my head. Everything below is what I wish someone had told me before I started.
What Is a Height Comparison Chart?
A height comparison chart is a picture where every figure is drawn at a size that matches its real height. If one person is 180 cm (5 ft 11 in) and another is 150 cm (4 ft 11 in), the first figure is drawn exactly 1.2 times taller. That ratio is the whole point. Photos lie about height all the time because of camera angle, shoes and posture. A chart drawn to scale cannot.
Let me explain the one rule that makes it work: everyone stands on the same floor line. Once the feet are level, any difference has to show at the top of the head. That is exactly what happens when two people stand back to back, only here you do not need them in the same room.
Why Compare Heights Visually Instead of Just Subtracting?
Subtracting works, but it gives you a number, not a feeling. A 10 cm (4 in) gap sounds small on paper. Seen on the chart, it is roughly a forehead's worth of difference, and most people are surprised by how clear it looks.
There is some science behind that surprise. Stanislas Dehaene, a cognitive neuroscientist at the Collège de France, has shown that we map numbers onto a fuzzy mental number line that gets compressed for values we rarely use. Height in inches or centimeters is one of those values. Drawing it makes the comparison concrete.
How to Compare Two Heights Step by Step
Here's the good news: this takes under a minute.
- Type a name and choose a male or female figure.
- Enter the height in feet and inches, or switch to centimeters.
- Pick a color and add the person.
- Repeat for anyone else, then read the difference card. It states who is taller and by how much, in both units.
Average Heights Around the World
It helps to know where a height sits. According to the CDC's anthropometric reference data for 2015 to 2018, the average adult man in the United States is about 5 ft 9 in (175 cm) and the average adult woman is about 5 ft 3.5 in (161 cm).
Globally, the range is wider than most people think. A 2016 study by the NCD Risk Factor Collaboration, published in the journal eLife, tracked adult height in 200 countries over a century. Dutch men came out tallest at around 182.5 cm (6 ft 0 in), and Guatemalan women shortest at around 149 cm (4 ft 11 in). Try adding those two to the chart. The gap is dramatic.
Things That Change a Height Reading
Based on what I've seen, most "he's not really 6 foot" arguments come down to measurement, not honesty. A few things move the number more than people expect:
- Time of day. A 1985 study in the journal Spine (Tyrrell, Reilly and Troup) measured people losing about 19 mm (0.75 in) between morning and evening as the discs in the spine compress. Measure in the morning if you want your tallest number.
- Shoes. Most sneakers add roughly 2 to 3 cm (about 1 in). Dress shoes and boots add more.
- Posture. Standing against a wall with heels, back and head touching it is the standard clinical method, and it usually gives a slightly taller reading than a casual stance.
- Rounding. 5 ft 11.5 in becomes 6 ft in conversation. The tool keeps the decimal.
Comparing Celebrities, Characters and Objects
The tool is not just for people you know. Two heights that make the scale click for most visitors: Shaquille O'Neal is listed at 7 ft 1 in (216 cm), and Danny DeVito at 4 ft 10 in (147 cm). Put them together and Shaq's figure is nearly 1.5 times DeVito's.
You can also add animals or objects by entering a height directly. A standard interior door is about 203 cm (6 ft 8 in), which is a handy reference when you want to see how someone measures against everyday things.
Is Height Mostly Genetic?
This is where it gets interesting. Twin studies, including a 2003 analysis by Karri Silventoinen and colleagues covering twin cohorts in eight countries, estimate that around 80% of the variation in adult height in well-nourished populations comes from genes. The rest comes from nutrition, childhood health and sleep.
That is also why average heights climbed through the twentieth century as diets improved, a trend the NCD-RisC study documents country by country.
What This Means for You
If you just want to settle a friendly argument, add both people and look at the difference card. If you are a writer or designer, use the chart to check that your characters' heights feel right next to each other. If you are tracking a child's growth, compare this year's height with last year's on one scale.
In every case the chart is a measurement, not an illustration. The ratio you see is the ratio that exists.
My honest take: height is one of those numbers people remember badly and argue about often. A height comparison chart does not change anyone's height, but it does end the debate quickly, and it is oddly fun to play with. Add a couple of people above and see for yourself. If something is unclear, the FAQ covers accuracy, units and sharing in more detail.