You are trying to picture 20 centimeters, but the number alone does not tell you much. You know it is a fairly small measurement, but how long is it actually?
20 centimeters equals 7.87 inches, which is just under 8 inches. That makes it easy to picture once you connect it to familiar objects such as a pencil, small ruler, kitchen knife, or the width of a hand.
This guide breaks down what 20 cm looks like, how to convert it to inches, and several everyday comparisons that make the measurement easier to visualize.
Quick Conversion: 20 Centimeters
Before getting into real-world comparisons, here is how 20 cm translates into other common units.
| Unit | Equivalent |
|---|---|
| Millimeters | 200 mm |
| Inches | 7.87 in |
| Feet | 0.656 ft |
| Meters | 0.20 m |
| Yards | 0.219 yd |
Quick mental anchor
Think of 20 cm as slightly shorter than 8 inches.
If you have an object that is exactly 8 inches long, 20 cm would be about 0.13 inch shorter. That small difference is difficult to notice without a ruler, which makes 8 inches an excellent mental reference.
Read more: How Many Inches in a Foot? (Complete Guide with Real Examples & Visuals)
What Does 20 Centimeters Actually Look Like?
On a metric ruler, 20 cm reaches exactly two-thirds of the way across a standard 30 cm ruler.
Another easy way to visualize it is to imagine two 10 cm sections placed end to end.
For a body-based comparison, the distance across many adult hands or the length from the wrist toward the base of the fingers can come close to 20 cm, although hand sizes vary considerably.
The important thing to remember is this:
20 cm = 200 mm = 7.87 inches.
It is long enough to be noticeable but still small enough to fit comfortably in one hand.
How to Convert 20 cm to Inches
The standard conversion is straightforward:
1 centimeter = 0.3937008 inches
So:
20 × 0.3937008 = 7.874016 inches
Rounded to two decimal places:
20 cm = 7.87 inches
For everyday measurements, 7.87 inches is precise enough. If you need a fraction, 20 cm is approximately 7 7/8 inches.
Simple conversion formula
Centimeters × 0.3937 = Inches
Therefore:
20 × 0.3937 = 7.874 inches
So the answer is approximately 7.87 inches.
10 Common Things That Are About 20 Centimeters Long
The easiest way to understand 20 cm is to compare it with things you already know.
1. A 20 cm School Ruler
A 20 cm ruler is the most direct comparison because it measures the exact length you’re trying to visualize.
Many small rulers are 15 or 20 cm long. If you have one nearby, place it on a table and look at the full length.
A 20 cm ruler is exactly 7.87 inches long, making it an almost perfect physical reference.
If your ruler is 30 cm long, 20 cm is exactly two-thirds of its total length.
2. A Standard Pencil
A typical unsharpened wooden pencil is around 17–19 cm long, depending on the design and whether it has an eraser.
That means a new pencil is often close to 20 cm, although not exactly.
Imagine a pencil measuring about 18 cm and add another 2 cm. You have a good approximation of the full 20 cm length.
This makes a pencil a useful everyday reference because most people have handled one.
3. A Medium Kitchen Knife Blade
Many kitchen knives have blades in the neighborhood of 18–20 cm.
For example, a medium chef’s knife may have a blade around 20 cm long, although knife dimensions vary by style and manufacturer.
If you picture a kitchen knife blade stretching from its handle to its tip, 20 cm is roughly the length of many medium-sized blades.
For safety, use this only as a visual comparison rather than as a measuring method.
4. The Width of a Small Tablet
Some compact tablets and similar electronic devices have widths approaching 20 cm, particularly when measured across the longer side of a smaller device in a particular orientation.
However, tablet dimensions vary substantially, so this is better treated as an approximate comparison rather than an exact 20 cm reference.
A useful mental image is a compact screen that is about 20 cm across.
5. A Small Hardcover Book
Many books have a height or width somewhere around 20 cm.
A typical trade-sized paperback is often smaller, while many hardcover books can be close to or greater than 20 cm on their longer side.
Place a book next to a ruler and you will quickly see that 20 cm is roughly the height of many compact books.
This is a convenient comparison when you are shopping online and trying to understand listed product dimensions.
6. A Large Adult Hand Span
Your hand can provide a useful approximate reference for 20 cm.
For some adults, the distance from the tip of the thumb to the tip of the little finger when the hand is fully stretched can approach 20 cm.
But hand spans vary significantly from person to person.
If your own hand span is close to 20 cm, it becomes a convenient personal measuring tool. Measure it once with a ruler and remember the result.
7. Two 10 cm Ruler Sections
This may sound obvious, but it is one of the easiest mental tricks.
Imagine two separate 10 cm lengths placed end to end.
10 cm is:
3.94 inches
Double that:
20 cm = 7.87 inches
So if you can comfortably picture 10 cm, simply double that mental length to estimate 20 cm.
8. A Large Dinner Plate Radius — Approximately
A dinner plate is usually much larger than 20 cm across. Many standard dinner plates have diameters around 25–30 cm or more.
However, 20 cm can represent a substantial portion of a plate’s diameter, depending on its size.
For example, on a 28 cm plate, 20 cm would cover about 71% of the diameter.
This is useful when you are trying to understand the dimensions of circular objects, but it should not be treated as a standard plate measurement.
9. A Compact Laptop or Keyboard Section
A section of a laptop keyboard or a compact laptop’s width can approach 20 cm.
For instance, 20 cm is roughly the distance you might see across several rows or a substantial section of a compact keyboard.
Because laptops come in many sizes, this is an approximate comparison rather than a standardized one.
Still, it can help when interpreting product specifications.
10. A Short Adult Forearm Section
The forearm is another useful body-based reference.
Depending on the person’s height and body proportions, a 20 cm section of the forearm can be easy to visualize. You can imagine measuring from the wrist toward the elbow.
Unlike a standardized object, however, human body measurements vary.
For the most accurate personal reference, measure your own forearm with a ruler and see how closely it matches 20 cm.
20 cm vs Other Common Measurements
Comparing 20 cm with nearby measurements can make the number easier to understand.
Smaller than 20 cm
- 5 cm = 1.97 inches
- 10 cm = 3.94 inches
- 15 cm = 5.91 inches
- 18 cm = 7.09 inches
- 19 cm = 7.48 inches
Larger than 20 cm
- 25 cm = 9.84 inches
- 30 cm = 11.81 inches
- 40 cm = 15.75 inches
- 50 cm = 19.69 inches
- 1 meter = 39.37 inches
The jump from 20 cm to 30 cm is especially easy to remember because 30 cm is the length of a common school ruler.
How Big Is 20 cm Compared With 8 Inches?
This is one of the easiest comparisons to remember.
8 inches = 20.32 cm
Meanwhile:
20 cm = 7.87 inches
That means 20 cm is only 0.32 cm shorter than 8 inches, or about 3.2 millimeters shorter.
So if someone tells you an object is 20 cm long, you can mentally picture something almost exactly 8 inches long.
For everyday visualization, saying “just under 8 inches” is usually the easiest way to understand it.
How Much Is 20 cm in Feet?
To convert centimeters to feet, divide the centimeter measurement by 30.48.
20 ÷ 30.48 = 0.656 feet
Therefore:
20 cm = 0.656 feet
That is less than one foot and is approximately 7.87 inches.
In feet-and-inches format, it is:
0 feet 7.87 inches
This is another reason inches are more useful than feet for describing a measurement as small as 20 cm.
What Is 20 cm in Inches as a Fraction?
If you need a fractional-inch estimate instead of a decimal, 20 cm is approximately:
7 7/8 inches
The exact conversion is approximately 7.874 inches.
Since 7/8 inch equals 0.875 inch, 7 7/8 inches is an extremely close practical approximation.
This can be useful for woodworking, crafts, sewing, and other situations where fractional inches are more familiar than decimals.
Where Does 20 Centimeters Come Up in Real Life?
Knowing what 20 cm looks like is useful beyond simple math.
Shopping
Online product descriptions often list dimensions in centimeters. Converting 20 cm to inches helps you judge whether a bag, gadget, container, decoration, or other item will fit your available space.
DIY and Crafts
Craft projects frequently involve centimeter measurements for spacing, cutting, templates, and material sizes.
Cooking
Some recipes and food-preparation instructions use centimeters when describing the size of cuts, dough shapes, pans, or other ingredients.
Education
Students regularly encounter centimeters when studying geometry, measurement, science, and unit conversions.
Home Organization
Shelf depth, storage containers, decorative objects, and small pieces of furniture can all have dimensions around 20 cm.
Clothing and Accessories
Small dimensions such as strap widths, accessory sizes, and bag measurements may be listed in centimeters, especially on international websites.
Quick Quiz: How Well Do You Know 20 Centimeters?
Test yourself before checking the answers.
Q1. How many millimeters are in 20 centimeters?
A) 20 mm
B) 100 mm
C) 200 mm
D) 2,000 mm
Q2. What is 20 cm in inches?
A) 5.87 inches
B) 7.87 inches
C) 8.87 inches
D) 10 inches
Q3. Which measurement is closest to 20 cm?
A) 2 inches
B) 5 inches
C) 8 inches
D) 12 inches
Q4. How many meters are in 20 cm?
A) 0.02 m
B) 0.20 m
C) 2 m
D) 20 m
Q5. A 30 cm ruler is how much longer than 20 cm?
A) 5 cm
B) 10 cm
C) 15 cm
D) 20 cm
Answers
- C — 200 mm
- B — 7.87 inches
- C — 8 inches
- B — 0.20 m
- B — 10 cm
Frequently Asked Questions About 20 cm in Inches
What is 20 cm in inches exactly?
20 centimeters equals 7.874016 inches. Rounded to two decimal places, it is 7.87 inches.
Is 20 cm the same as 8 inches?
Not exactly. 8 inches equals 20.32 cm, so 20 cm is about 0.32 cm shorter than 8 inches.
Is 20 cm a big measurement?
20 cm is a relatively small length. It is about 7.87 inches, making it easy to hold in one hand and common in small household objects, tools, books, and electronics.
What is 20 cm in feet?
20 cm equals approximately 0.656 feet.
What is 20 cm in inches as a fraction?
20 cm is approximately 7 7/8 inches.
How many millimeters are in 20 cm?
There are 200 millimeters in 20 centimeters because 1 centimeter contains 10 millimeters.
Can I estimate 20 cm without a ruler?
Yes. The easiest mental reference is just under 8 inches. You can also use a 20 cm ruler, a nearby pencil, or a measured section of your own hand as a rough reference.
Is 20 cm longer than a 15 cm ruler?
Yes. 20 cm is 5 cm longer than 15 cm.
In inches, 15 cm is about 5.91 inches, while 20 cm is about 7.87 inches.
How many inches are 20 cm and 30 cm together?
Together, 20 cm + 30 cm equals 50 cm.
50 cm = 19.69 inches.
What everyday objects are about 20 cm long?
Depending on the specific size, examples can include a 20 cm ruler, a typical pencil, some kitchen knife blades, compact books, and certain electronic devices.
Because manufactured objects vary, these should be treated as visual comparisons rather than exact measurements.
Conclusion
20 cm is equal to 7.87 inches, or approximately 7 7/8 inches.
The easiest way to remember it is to think “20 centimeters is just under 8 inches.” From there, objects such as a 20 cm ruler, pencil, small book, kitchen knife blade, or a measured section of your hand can make the length much easier to visualize.
Once you have one reliable mental reference for 20 cm, you can estimate the size of objects much faster without reaching for a calculator every time.
If you regularly work with metric measurements, remember these three conversions:
20 cm = 200 mm = 7.87 inches = 0.20 meters.
Read more: What Is 70 Inches in Feet? 18 Everyday Comparisons Explained
