Linear Inches Calculator for Luggage
Enter your bag's three dimensions and this calculator adds them into a single linear-inch total, then tells you which airline size tiers your bag qualifies for: personal item, standard carry-on, standard checked, or oversized. Switch between inches and centimetres at any time. The result updates as you type.
Formula
Worked example
A checked suitcase measuring 27 in x 20 in x 12 in: 27 + 20 + 12 = 59 linear inches (149.9 cm), which is 3 inches under the standard 62 in airline limit.
What are linear inches?
Linear inches is a single number that summarises the overall size of a three-dimensional object by adding together its length, width, and height. Airlines use this total rather than any one dimension because it captures how much space a bag occupies in the hold. The formula is simply: linear inches = length + width + height, all measured in inches. The equivalent metric measure is linear centimetres, calculated the same way but in centimetres (62 in = approximately 157-158 cm). Most major airlines set 62 linear inches as the standard maximum for a checked bag and 45 linear inches for a carry-on.
How to measure your luggage correctly
Measure the bag when fully packed and closed. Include any wheels, feet, or handles that protrude beyond the main shell: these add to the true linear-inch total even if the manufacturer's size label ignores them. Use a soft measuring tape or a ruler on a flat surface. Measure the longest side (length), then the front-to-back depth (width), then the side-to-side height. Add all three numbers and compare to your airline's limit. A bag that is right on the edge may still pass at check-in, because real enforcement tolerates a small amount of flex in soft-sided cases, but hard-shell bags get less benefit of the doubt.
Carry-on vs. checked bag limits explained
Most US carriers allow carry-on bags up to 45 linear inches (approximately 22 x 14 x 9 inches or 56 x 36 x 23 cm). The standard checked-bag limit is 62 linear inches (typically about 27 x 21 x 14 inches or 69 x 53 x 36 cm). Bags measuring 63 to 80 linear inches are classed as oversize and attract an oversize fee, which on major US airlines runs from about USD 100 to USD 200 per bag each way as of 2026. Bags above 80 linear inches may be refused entirely or require advance cargo booking. International carriers and budget airlines often apply different or tighter thresholds, so always check before you fly.
Tips to avoid oversize fees
If your bag is just over the standard limit, try packing a little lighter so soft-sided walls compress slightly. Choosing a bag with a larger frame but soft sides gives you more real packing volume for the same linear-inch footprint. Wheels and telescoping handles are the most common culprits for pushing a bag over the limit: look for bags marketed as "62 linear inch" to be sure the manufacturer has already accounted for these protrusions. Shipping your bags with a luggage-forwarding service can sometimes be cheaper than paying oversize fees, especially for longer trips where you check the bag both ways.
Airline luggage size limits (2026)
| Bag type | Max linear inches | Max linear cm | Typical oversize fee (USD) |
|---|---|---|---|
| Personal item (under seat) | 36 in | 91 cm | None (free) |
| Carry-on (overhead bin) | 45 in | 114 cm | None if within limit |
| Standard checked bag | 62 in | 158 cm | None if within limit |
| Oversize checked bag | 63-80 in | 160-203 cm | $100 - $200 per bag |
| Refused / cargo only | Above 80 in | Above 203 cm | Varies / may be refused |
Standard limits used by most major airlines. Always verify your specific carrier's current policy before travel, as limits and fees change.
Frequently asked questions
What does "linear inches" mean for luggage?
Linear inches is the sum of a bag's three outer dimensions: length + width + height, all in inches. Airlines use this single number to enforce consistent size limits across bags of different shapes. A standard checked bag must not exceed 62 linear inches on most major carriers, and a standard carry-on must not exceed 45 linear inches.
How do I convert linear inches to centimetres?
Multiply linear inches by 2.54. For example, 62 linear inches equals 62 x 2.54 = 157.48 cm, which airlines round to 158 cm. You can also measure each dimension in centimetres and add them directly for the linear-centimetre total, then divide by 2.54 to get linear inches.
Do airlines measure bags at the airport?
Airlines can and sometimes do measure bags at check-in, but enforcement is inconsistent. Carry-on limits are checked more rigorously on flights where overhead space is tight, especially on regional jets. Checked bags that are clearly oversized (large sports equipment, bulky suitcases) are measured before tags are attached. When in doubt, measure before you leave home.
What is the standard checked-bag limit in linear inches?
The industry standard for checked bags on most North American carriers is 62 linear inches (approximately 158 cm). This applies to United, Delta, American, Southwest, and most other major US airlines. Budget carriers and international airlines may set different limits, so check your specific airline's baggage policy page before you travel.
Does 62 linear inches include wheels and handles?
Yes. Airlines measure the outside of the bag as it sits in the belt or on the scale, including protruding wheels, feet, and handles. Always measure your bag in its travel-ready state with all external protrusions included. A bag labelled "62 linear inch" by the manufacturer should already account for these, but verify by measuring yourself.
What happens if my bag is over 62 linear inches?
A bag measuring 63 to 80 linear inches is classified as oversize and typically incurs a surcharge on top of the standard checked-bag fee. US carrier rates in 2026 run from about USD 100 to USD 200 per bag per direction. Bags above 80 linear inches may be refused at check-in or require advance special-handling booking as cargo.
Can I carry a 62 linear inch bag as a carry-on?
No. The carry-on limit on most airlines is 45 linear inches. A 62 linear inch bag is far too large for an overhead bin or under-seat storage and must be checked. Even some hard-sided carry-on bags marketed as "maximum size" measure right at 45 linear inches, so check the dimensions before buying.