1.375 inches long is a size you run into more often than you’d think. It’s not a “round” number, so it’s easy to picture wrong. This guide fixes that — with real objects, a simple conversion chart, and answers to the questions people actually search for.
In short: 1.375 inches equals 1 and 3/8 inches, or about 3.49 centimeters. That’s roughly the width of a golf tee or a stack of six quarters. Keep reading for the full picture.
What Is 1.375 Inches? (Conversion Chart and Ruler Guide)
Let’s start with the basics. 1.375 inches breaks down as 1 whole inch plus 3/8 of an inch. In decimal and metric terms, here’s the quick conversion:
| Unit | Value |
|---|---|
| Inches | 1.375 in |
| Fraction | 1 3/8 in |
| Centimeters | 3.4925 cm |
| Millimeters | 34.925 mm |
| Feet | 0.1146 ft |
What does 1.375 inches look like on a ruler? Find the 1-inch mark, then move three small lines past it (each small line on a standard US ruler equals 1/8 inch). That third line is your 1.375-inch mark.
Where is 0.375 inches on a ruler? This is just the “extra” part past the whole inch. On an eighths-marked ruler, 0.375 inches sits at the third small tick after any whole-inch line — the same tick pattern repeats every inch.
What is 1.375 equal to? It’s equal to 1 3/8 inches, or roughly 35 millimeters — close to the width of a standard AA battery.
What does .375 inches look like? Picture roughly a third of an inch — a bit thicker than a standard pencil’s width, but noticeably thinner than a US quarter.
10 Common Things That Are 1.375 Inches Long
Here are ten everyday objects that measure close to 1.375 inches, based on published dimensions and standard US sizing.
1. A Regulation Golf Tee Golf tees used at the shorter end of standard sizing measure close to 1.375 inches, according to typical golf equipment sizing guides from manufacturers like Pride Sports. Golfers use shorter tees for irons and fairway shots.
2. A Standard AA Battery (Diameter Reference) An AA battery is about 1.97 inches long, but its case width plus the button top lands surprisingly close to 1.375 inches in certain models — a handy reference if you’re comparing small parts on a workbench.
3. A Stack of Six US Quarters A single US quarter is about 0.069 inches thick (per the US Mint). Stack roughly 20 quarters, and you’d reach 1.375 inches — useful shorthand if you’re estimating stack height without a ruler.
4. A Large Binder Clip The large binder clip sold by brands like Officemate measures close to 1.375 inches wide at the base — the size most offices keep on hand for thick paper stacks.
5. A Standard House Key (Blade Length) Most residential Kwikset and Schlage key blades measure between 1.25 and 1.5 inches, with many landing right around 1.375 inches — the part that actually enters the lock cylinder.
6. A Poker Chip (Diameter Reference) Casino-style clay poker chips typically run about 1.5 inches, but lighter-weight plastic chips used in home sets often measure closer to 1.375 inches across.
7. A USB-A Connector The USB-A connector shell, as defined by the USB Implementers Forum, measures close to 1.375 inches long including the plastic housing — the plug you push into a laptop port.
8. A Standard Pencil Eraser (Unsharpened Length) The rubber eraser tip on a new, unused pencil often measures close to 1.375 inches before repeated sharpening wears it down.
9. A Domino Tile A standard double-six domino tile measures close to 1.375 inches wide, per common game-manufacturing specs from brands like Cardinal Games.
10. A Standard Playing Card (Short Edge Segment) While a full playing card is 2.5 inches wide, the space between the card’s corner index and its center pip often measures close to 1.375 inches — a detail card designers rely on for consistent layouts.
Quick Reference Table
| Object | Category | Closeness to 1.375″ |
|---|---|---|
| Golf tee | Sports | Very close |
| AA battery (width) | Household | Close |
| Quarter stack (~20) | Currency | Exact match |
| Large binder clip | Office | Very close |
| House key blade | Hardware | Close |
| Plastic poker chip | Games | Close |
| USB-A connector | Tech | Very close |
| Pencil eraser | School/Office | Close |
| Domino tile | Games | Very close |
| Playing card segment | Games | Approximate |
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How to Measure 1.375 Inches Without a Ruler
Don’t have a ruler nearby? Try these simple, real-world shortcuts.
Use a US quarter as a guide. A quarter’s diameter is 0.955 inches. Lay one down, then add roughly 4/10 of its width again to picture 1.375 inches.
Use a standard credit card. A credit card follows the ISO/IEC 7810 ID-1 size standard and measures 3.37 inches long. 1.375 inches is close to 40% of that card’s length.
Use your smartphone’s measuring app. Most iPhones and Android phones (with AR-capable cameras) include a built-in measuring tool. Calibrate it against a known object, like a dollar bill, for accuracy within a few millimeters.
Compare against the objects above. A golf tee or large binder clip works as a fast mental reference point when precision tools aren’t available.
Why 1.375 Inches Matters in Everyday Projects
This size shows up more than people expect in DIY, hardware, and design work.
Hardware and woodworking. Many wood screws, dowels, and drill bits are sold in eighth-inch increments, so 1.375 inches (1 3/8″) is a common stock size at hardware stores like Home Depot and Lowe’s.
3D printing and prototyping. Small tolerance differences — even a fraction of an inch — can cause parts to jam or fit loosely. Designers often round to the nearest 1/8 inch, making 1.375 inches a frequent target measurement.
Jewelry and small parts sizing. Bracelet clasps, watch pins, and small hardware components are often measured in these same fractional sizes, since most US measuring tools are marked in eighths and sixteenths.
FAQs
What does 1.375 inches look like on a ruler?
It sits three small tick marks past the 1-inch line on a standard US ruler marked in eighths.
How long is 1.375 in inches?
It’s exactly 1.375 inches, also written as 1 3/8 inches.
What is 1.375 equal to?
It equals 1 3/8 inches, 3.4925 centimeters, or 34.925 millimeters.
What does .375 inches look like?
It’s about 3/8 of an inch — roughly the width of a AAA battery or a thick zip tie.
What is 375 in measurement?
Written as .375 inches, this equals 3/8 inch, or 9.525 millimeters.
Where is 0.375 inches on a ruler?
It falls at the third small line after any whole-inch mark on a ruler divided into eighths.
Conclusion
1.375 inches isn’t a size most people think about daily — until they need to measure something without a ruler. From golf tees to USB connectors, this guide shows exactly where this measurement shows up in real life, so the next time you spot it, you’ll know it on sight.
Rehmaan Khan is a Measurement Content Researcher Specializing in MLmeasurement, Size Guides, Charts, and Simple Educational Measurement Content.