By now, you know that it will probably cost you to check a bag on a flight. But travelers are really getting nailed with oversized luggage.

An easy way for airlines to earn revenue is to charge for overweight and oversized bags.

If your luggage is overweight, it may be possible to redistribute items between checked and carry-on.

But if you’re caught with an oversized bag, expect to pay between $50 and $150.

All airlines have luggage limits, but it varies between airline, your class of ticket and frequent-flier status, and whether you’re flying domestically or internationally.

Bags are measured by linear inches, which is the total length plus width plus height.

On domestic coach seats, it’s generally 62 linear inches for checked, and 45 linear inches for carry-on. But watch out.

Rules can change and if you’re not paying attention you could get caught.

Last year, Continental and US Airways reduced their carry-on size required from 51 linear inches to 45.

Your best bet is to check with the airline to find out the latest information.

Another great resource is LuggageLimits.com, which lists the baggage restrictions for each airline based on your route.

Or, you can do what Peter does on domestic flights. Send luggage ahead of time with a shipping service like UPS or FedEx, and save yourself a lot of hassle.

Learn more in our Luggage & Packing section.

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