How To Check What Size My Laptop Is | Know Your Screen Size

Most laptops are sized by the diagonal screen in inches, measured corner-to-corner, not by the width of the keyboard or the outer shell.

You’ve got a laptop in front of you, and you just need the size. Maybe you’re buying a sleeve, replacing a screen, ordering a privacy filter, or listing it for sale. The annoying part is that “15-inch laptop” can mean two different things: the screen diagonal (what brands advertise) and the physical body (what actually needs to fit in your bag).

This walks you through both, step by step. You’ll end up with two numbers that settle the whole thing: your screen size in inches and your laptop’s outer dimensions in real units.

What “Laptop Size” Usually Means

When most people say “laptop size,” they mean the screen size: the diagonal measurement of the visible display area, given in inches. That’s the number you see in product names like 13.3, 14, 15.6, or 17.3.

There’s a second size that matters just as much: the chassis size. That’s the width, depth, and thickness of the laptop body. Two laptops with the same screen diagonal can have different body sizes because of bezels, hinge design, and the shape of the frame.

Two Numbers To Capture

• Screen diagonal (inches): Used for screens, privacy filters, replacement panels, and “fits a 15.6-inch laptop” products.
• Outer dimensions (mm or inches): Used for sleeves, backpacks, stands, docks, and shipping boxes.

What You’ll Need Before You Start

You can do this with almost nothing. A flexible tape measure is the easiest. If you don’t have one, a rigid ruler works, and a phone measuring app can still get you close when you’re careful.

Grab One Of These

• A tape measure with inches marked (best)
• A ruler (fine, just takes longer)
• Paper and pen (to write down your results)

Clean the screen first if it’s dusty. You’ll spot the true corners faster.

How To Measure Screen Size With A Tape Measure

This is the most direct method, and it works on any laptop brand. The trick is measuring only the visible display area, not the frame around it.

Step-By-Step: Diagonal Screen Measurement

1. Open the laptop so the screen is upright and easy to reach.
2. Find the visible screen corners. That’s the lit area, not the bezel.
3. Place the “0” end of the tape on the top-left visible corner.
4. Pull the tape to the bottom-right visible corner.
5. Read the diagonal measurement in inches.
6. Round to the nearest common size (13.3, 14, 15.6, 16, 17.3).

If your tape is in centimeters, measure the diagonal in cm, then divide by 2.54 to get inches. Don’t measure from the outer plastic edge. That’s how people end up “inventing” a bigger screen than they own.

Rounding Without Guesswork

Laptop screens often land on decimals. A 15.6-inch screen rarely measures exactly 15.60 on your tape because you’re measuring the visible area, and bezels can hide a sliver. If you measure around 15.4–15.6, it’s almost always sold as 15.6.

How To Check Screen Size In Settings Without Measuring

If you can’t measure right now, your device can still point you to the size. Settings usually won’t show the diagonal inches directly, but they can give you the model name, display resolution, and scale details that help you confirm what you have.

Windows: Find The Model And Specs Fast

On Windows, your goal is to grab the device model, then match it to the official spec sheet for your exact configuration.

1. Open Settings.
2. Go to System > About.
3. Copy the Device name, System model, and Device specifications.

Microsoft also outlines where to find these device details here: Find your device specifications in Windows.

macOS: Identify The Exact MacBook Model

For MacBooks, the model identification is clean and reliable.

1. Click the Apple menu.
2. Select About This Mac.
3. Note the model name and year.

Apple explains model identification steps here: Identify your MacBook model.

Chromebook: Confirm The Model Name

Chromebooks vary a lot by maker, so model name is your anchor.

1. Open Settings.
2. Go to About ChromeOS.
3. Look for device details and model information.

Linux: Pull Hardware Info From The System

On Linux, you can still get the model without hunting around stickers. If you’re comfortable in a terminal, you can check the system’s DMI data and match the model to the maker’s published specs.

How To Check What Size My Laptop Is With Confidence

If you want the answer you can trust, pair two checks: measure the diagonal screen, then confirm the model in settings. When both line up, you’re done. When they don’t, the mismatch usually comes from measuring the bezel or reading the model too broadly.

Use this table to pick the right method for your situation. It’s also handy when you’re buying something that demands the correct number the first time.

Method	What You’ll Learn	When It Fits Best
Tape measure, corner-to-corner	Screen diagonal in inches	Privacy filters, replacement screens, screen protectors
Ruler + diagonal math	Screen diagonal in inches	When you don’t have a flexible tape
Windows Settings > System > About	Model name and device specs	Confirming size before you order parts
About This Mac	MacBook model and year	Matching Apple size labels (13-inch, 14-inch, 16-inch)
Sticker on the bottom panel	Model code or SKU	When the system won’t boot
Manufacturer spec sheet by model code	Screen size plus chassis dimensions	Buying a sleeve or checking desk fit
Measure the laptop body (W × D × T)	Outer dimensions in inches or mm	Bags, stands, docking clearance, shipping boxes
Resolution + aspect ratio check	Clues that confirm size class	Spotting mismatched listings when buying used

How To Measure The Laptop Body For Sleeves And Bags

This is the number that saves you from a sleeve that “should fit” but doesn’t zip. Measure the body with the laptop closed, sitting on a flat surface.

Step-By-Step: Width, Depth, Thickness

1. Width: Measure left edge to right edge across the widest point.
2. Depth: Measure front edge to back edge.
3. Thickness: Measure bottom to top at the thickest point.

Write it down as W × D × T. If you’re shopping online, keep the units consistent. Many bag listings use millimeters, while many tape measures in the US show inches.

Small Fit Tricks That Save Returns

• If your laptop has rubber feet that stick out, include them in thickness.
• If the hinge bulges at the back, measure depth at the hinge point, not the palm rest.
• If you use a hard shell case, measure with it installed.

Screen size alone doesn’t guarantee a fit. A “15-inch” laptop can be compact, while a “14-inch” with thick bezels can take up more space than you’d expect.

How Aspect Ratio Changes What You See

Two laptops can share the same diagonal inches and still look different in shape. That’s aspect ratio: the relationship between width and height of the display. Common laptop ratios include 16:9 and 16:10. Some devices also use 3:2.

Why this matters: accessories that cover the screen, like privacy filters and some protectors, can be picky about aspect ratio. A 14-inch 16:9 panel and a 14-inch 16:10 panel don’t have the same height.

Fast Ways To Spot It

• Check your display resolution in settings.
• Look for patterns like 1920×1080 (often 16:9) or 1920×1200 (often 16:10).
• On a used listing, ask for a photo of the resolution screen if the seller can’t name it.

Common Laptop Screen Sizes And What They Usually Pair With

This table won’t identify your laptop by itself, but it helps you sanity-check what you measured. If your tape says 13.9 inches, you’re almost certainly in the 14-inch class. Then your model lookup should agree.

Screen Size (Inches)	Common Resolution Patterns	Typical Fit
11.6	1366×768	Small Chromebooks, compact travel machines
13.3	1920×1080, 2560×1600	Thin laptops, many older ultraportables
14	1920×1080, 1920×1200, 2880×1800	Balanced size for work and school
15.6	1920×1080, 1366×768	Mainstream laptops with roomier keyboards
16	2560×1600, 1920×1200	Roomy screens in slimmer bodies
17.3	1920×1080, 2560×1440	Large laptops, many gaming models
18	2560×1600, 3840×2400	Extra-large performance laptops

When The Sticker On The Bottom Beats Everything Else

If your laptop won’t turn on, the bottom label can still get you the answer. Look for a model number, product number, or SKU. It may be near the vents or under a small flap.

Once you have that code, search it with the brand name and “specs.” Match the screen size and the chassis dimensions from the published spec page. Watch for listings that group multiple screen options under one family name. You want the exact suffix or configuration code when it’s available.

What To Write Down From The Label

• Model name (often short and readable)
• Model number (often a longer code)
• Serial number (useful for maker lookup tools)

Don’t share your serial number publicly when you’re posting a listing. Keep that part private.

How To Avoid The Most Common Measuring Mistakes

Most wrong answers come from one of these slips. Fix them once, and you won’t need a second round of returns.

Measuring The Bezel Instead Of The Display

If you measure from the outer plastic corners, you’ll overshoot. Screen size is the lit rectangle only. Start and end at the visible corners.

Mixing Up Screen Size And Body Size

A sleeve that says “fits 15.6-inch laptops” is vague unless it lists internal dimensions. Always compare the bag’s internal W × D × T to your laptop’s outer W × D × T.

Rounding The Wrong Way

Rounding is normal, but keep it close to the common size classes. If you measure 15.5, it belongs in 15.6. If you measure 13.2, it belongs in 13.3. If you land between classes, do a second measurement to confirm your tape placement.

Buying The Right Accessory With Your Numbers

Once you have screen diagonal and outer dimensions, buying gets simpler. Use the right number for the right product.

For Sleeves, Bags, And Backpacks

• Match your laptop’s outer width and depth to the bag’s internal size.
• Give yourself a little breathing room for zippers and padding.
• If the bag lists only “13-inch” or “15-inch,” look for a spec chart or skip it.

For Privacy Filters And Screen Protectors

• Use the diagonal inches plus the aspect ratio.
• Confirm the resolution pattern in settings to avoid ordering the wrong shape.

For Replacement Screens

Screen replacement needs more than inches. You’ll also need panel type and connector details. Your model code is your starting point, and the display part number is the safest match when you can get it.

A Simple Checklist You Can Save

If you want a clean “done” moment, run this quick list and stash the results in your notes app.

• Screen diagonal (inches): ________
• Aspect ratio guess (16:9, 16:10, 3:2): ________
• Resolution shown in settings: ________
• Model name / model code: ________
• Outer width × depth × thickness: ________

That’s it. With those numbers, you can shop, replace parts, or list your laptop with zero confusion and fewer returns.