To calculate linear inches for luggage, add together its length, width, and height measured in inches.
Airlines talk about linear inches a lot, yet many travelers measure a suitcase once, shrug, and hope for the best at the check-in desk. A few minutes with a tape measure before you leave home can spare you fees, repacking stress, and last minute drama at the counter.
This guide walks through what linear inches mean for luggage, how to measure a bag correctly, and how airline limits usually work. By the end, you will know exactly how to check any suitcase against common rules at home.
What Does Linear Inches Mean For Luggage?
Linear inches describe the total outside size of your luggage. Instead of asking you to remember three separate dimensions, airlines often care about their sum. That one number lets them judge whether a bag is within size limits for overhead bins or the cargo hold.
The formula is simple:
- Measure the length of the bag in inches.
- Measure the width in inches.
- Measure the height or depth in inches.
- Add the three numbers together.
So if a suitcase is 28 inches long, 18 inches wide, and 12 inches deep, the linear measurement is 58 inches. The same idea applies to smaller carry-on bags or bulky checked luggage.
| Bag Type | Example Size (L × W × H) | Linear Inches Total |
|---|---|---|
| Small Personal Item | 16 × 12 × 6 in | 34 in |
| Compact Carry-On | 20 × 13 × 9 in | 42 in |
| Standard Carry-On | 22 × 14 × 9 in | 45 in |
| Medium Checked Suitcase | 26 × 18 × 10 in | 54 in |
| Large Checked Suitcase | 28 × 18 × 12 in | 58 in |
| Typical 62″ Checked Bag | 30 × 20 × 12 in | 62 in |
| Oversize Duffel | 34 × 18 × 14 in | 66 in |
How Do You Calculate Linear Inches For Luggage?
When you hear travelers ask, “how do you calculate linear inches for luggage?”, they are usually trying to avoid surprise fees on a trip they have already booked. The good news is that the process is quick, and you do not need anything more than a flexible tape measure and a flat surface.
Step 1: Place The Bag On A Flat Surface
Set your suitcase on the floor or a table, wheels down. Make sure handles, straps, and pockets sit the way they would during check-in. Airline staff measure bags as they come, so your numbers should match that real world shape.
Step 2: Measure Length, Width, And Height
Start with the longest side, usually the height from wheels to the top handle. Then measure the width across the front, followed by the depth from the front panel to the back. Include handles, wheels, and any rigid external pockets, since many airlines count those in the total size.
Step 3: Add The Three Measurements
Write the three numbers down, then add them together. Length plus width plus height equals the linear inches for that piece of luggage. You can do this on paper, with a phone calculator, or with an online linear inches calculator if you prefer digital tools.
Extra Measuring Tips
- If your tape shows centimeters, divide each dimension by 2.54 to convert to inches before you add them.
- Round up to the nearest whole inch so you stay on the safe side of airline rules.
- Measure each suitcase separately. Airlines usually apply size limits per bag, not across your whole set.
Linear Inches For Luggage Measurement Rules
Once you know how to calculate linear inches for luggage, the next step is matching your numbers to airline limits. While each carrier sets its own rules, many follow a pattern for standard economy tickets.
Typical Checked Bag Limits
For checked bags on many major airlines, the common size limit is 62 linear inches. That means the sum of length, width, and height must be 62 inches or less. One common case is a 30 × 20 × 12 inch suitcase, which adds up exactly to 62 linear inches.
On some routes or fare types, the allowance may differ, and oversized bags often bring extra charges. Carriers such as Delta spell out these rules clearly. The Delta baggage policy states that standard checked luggage may not exceed 62 inches when you total length, width, and height.
United publishes a similar limit. On the airline’s checked baggage page, the example maximum size is 30 × 20 × 12 inches, again equal to 62 total inches when you add the three sides together. You can read the current details under the United checked baggage size rules.
Carry-On And Personal Item Limits
Carry-on bags are often measured with fixed dimensions instead of a linear inches sum, such as 22 × 14 × 9 inches. That still adds up to a linear total, though, which usually sits between 45 and 50 inches. Personal items like small backpacks or under-seat bags come in under that range.
Even if your airline lists a three number size box instead of a linear inches limit, you can still use the same formula. Add length, width, and height, then compare that number with the checked bag rules to see whether a bag needs to be checked or can stay with you in the cabin.
Common Airline Linear Inch Limits
To put the formula into context, it helps to see how several airlines phrase their rules. These numbers can shift over time, so always compare your ticket with the carrier’s current baggage page before you fly. Still, a pattern shows up when you scan the policies for checked luggage.
| Airline | Max Checked Bag Linear Inches | Notes |
|---|---|---|
| Delta Air Lines | 62 in | Standard economy checked bag limit. |
| United Airlines | 62 in | Example bag size 30 × 20 × 12 in. |
| American Airlines | 62 in | Common limit on many routes. |
| Air Canada | 62 in | Listed as 158 cm linear dimensions. |
| Lufthansa | 62 in | Width + height + depth up to 158 cm. |
| Budget Carriers | Often 62 in | May apply stricter weight rules. |
The table does not replace your airline’s own baggage page, yet it shows why travelers hear the number 62 so often. The same linear inches threshold appears with many full service carriers around the world, even though weight limits and fees can differ.
Frequent Mistakes With Linear Inches
Knowing how to calculate linear inches for luggage is half the story. The other half is avoiding small measuring habits that push a bag over the limit without you realising it. A few details come up again and again when airport staff measure bags at the counter.
Ignoring Handles And Wheels
Many travelers measure just the hard shell of a suitcase and forget handles, corner reinforcements, or oversized wheels. Ground staff often include those parts when they place a bag against a measuring frame or tape. If your bag already sits near the limit, those extra inches can move it into oversize territory.
Using Old Size Tags
Suitcases sometimes ship with dimension tags on the handle. Those numbers may exclude wheels or only list interior space. They can also round down the size to look more travel friendly. Always trust your own tape measure more than a marketing tag on the bag.
Measuring Only One Direction
Some travelers read the largest dimension on their suitcase and assume that number alone tells them whether a bag fits the rules. Linear inches combine all three sides, so a slightly taller but slim bag can pass while a shorter, bulky duffel fails. Only the sum gives you a clear answer.
Checking Luggage Size At Home Without Stress
Once you understand linear inches for luggage, you can build a simple home routine before each trip. This habit works well if you share luggage between family members or switch airlines often.
Create A Quick Reference Card
Write down the standard checked bag limit of 62 linear inches, along with typical carry-on dimensions for the airlines you use most. Keep that card in a drawer near your bags, or save it as a note on your phone. When you buy new luggage, compare the numbers on the spot.
Measure Packed Bags, Not Empty Shells
Soft suitcases can bulge outward once they are packed to the limit. Zip every compartment, expand any extension zippers you plan to use, and then measure. This gives you a realistic view of the size airlines will see when the bag rolls across the check-in scale.
Combine Size Checks With Weight Checks
Most checked bag policies tie linear inches limits together with weight caps. Weigh each suitcase after you measure the size. A basic home scale, plus one more quick measurement session, can spare you overweight and oversize fees on the same trip.
Quick Linear Inches Tips For Upcoming Trips
Linear inches for luggage do not need to feel mysterious. Once you measure a few bags, the math becomes second nature.
You can note the linear inches for each suitcase on a small tag, so you never repeat the same measurement work.
- Measure length, width, and height in inches, including wheels and handles.
- Add the three numbers to get linear inches for each piece of luggage.
- Compare that total with your airline’s checked and carry-on limits, aiming to stay a little below the maximum.
- Recheck dimensions whenever you pack a suitcase to the brim or use expansion zippers.
With that simple habit, you can answer the question “how do you calculate linear inches for luggage?” for any bag in your closet, long before a gate agent reaches for a tape measure.