Measure length, width, and depth with a tape measure or ruler

To measure luggage, you need the three dimensions: length (the longest side from top to bottom), width (side to side), and depth (front to back). Use a soft tape measure or a rigid ruler, and measure the outside of the bag at its widest points. Write down all three numbers in inches or centimeters — whichever your airline or venue requires.

The tricky part is knowing where to measure. For a rolling suitcase, measure from the top handle down to the bottom wheel, then across the widest part of the bag, then from the front to the back. For a duffel or soft-sided bag, lay it flat on the ground and measure each dimension at the bulkiest point, not where the fabric sags.

If your bag has wheels, handles, or pockets that stick out, measure around them — include those in your width and depth measurements. Airlines measure the outside of the bag as it sits, not the interior space.

Key Takeaways

  • Measure the outside of your bag at its widest points in all three directions: length, width, and depth.
  • For rolling luggage, measure from the top of the handle to the bottom of the wheel, and include wheels and handles in your measurements.
  • Soft-sided bags should be measured at their fullest point when laid flat, not when they sag or compress.
  • Add all three dimensions together to get your total linear inches (or centimeters), which is what most airlines use for size limits.
  • Measure your bag before you pack it, then measure again when it is full to see if it exceeds the airline's maximum.

Add the three dimensions to find your linear measurement

Most airlines do not care about the individual measurements — they care about the linear measurement, which is length plus width plus depth. If your suitcase is 22 inches long, 14 inches wide, and 9 inches deep, your linear measurement is 22 + 14 + 9 = 45 inches.

This number is what you will see in airline baggage policies. A typical carry-on limit is 22 × 14 × 9 inches (45 inches linear), and a typical checked bag limit is 29 × 20 × 11 inches (60 inches linear). If your bag adds up to more than the limit, it will not fit in the overhead bin or may be rejected at check-in.

Keep your measurements written down or take a photo of them. You will need them when you book your flight or when you are packing to make sure you stay under the limit.

Measure soft-sided bags when they are fully packed

Soft duffels, backpacks, and expandable suitcases change size depending on how full they are. If you measure an empty soft bag, you might think it fits the size limit, but once you pack it, it could bulge over the edge. Measure your soft-sided bag after you have packed it the way you plan to travel.

If your bag has an expandable section or zipper that adds depth, measure it in the expanded position if you plan to use that expansion. Some airlines allow a small amount of expansion (usually up to 2 inches), but others do not — check your airline's policy before you rely on that extra space.

For backpacks and hiking bags, measure at the widest point of the packed bag, including any straps or pockets that stick out. Compression straps do not count — measure the bag as it naturally sits when full.

Know the difference between airline and venue size limits

Airlines measure luggage one way, but hotels, cruise ships, and event venues may measure differently. Airlines use linear inches (the sum of all three dimensions). Some venues specify each dimension separately — for example, "no larger than 22 × 14 × 9 inches." Others give a weight limit instead of a size limit.

Before you travel, check the specific rules for your airline, hotel, or venue. The airline's website will list carry-on and checked bag dimensions. Cruise lines often have stricter limits than airlines. Hotels rarely restrict luggage size, but some do. Event venues (like conferences or festivals) sometimes limit bag size for security reasons.

If you are traveling with multiple bags, measure each one separately. Some airlines allow one carry-on plus one personal item (like a purse or small backpack), and each has its own size limit.

Use a luggage scale to check weight at the same time

Size is only half the story — weight matters too. Most airlines allow 50 pounds for a checked bag and 25 pounds for a carry-on, though these limits vary. A luggage scale is a small digital scale you can buy for $15 to $30 that hangs from your bag's handle and shows the weight when ready.

Weigh your packed bag before you leave home. If it is over the limit, you can remove items and repack before you get to the airport. This saves you from paying overweight fees or having to leave items behind at the counter.

If you do not have a luggage scale, you can weigh yourself on a bathroom scale, then weigh yourself holding the bag and subtract the difference. It is not as precise, but it gives you a rough idea.

Check your airline's specific rules before you pack

Every airline has different size and weight limits, and they change. Some airlines are strict about carry-on dimensions and will gate-check bags that are even slightly over. Others are more lenient. Budget airlines often have smaller limits than full-service carriers.

Look up your specific airline on their website and find the baggage policy page. Write down the exact dimensions and weight limits for both carry-on and checked bags. If you are flying with a connecting flight on a different airline, check both airlines' policies — you have to meet the strictest limit.

If your bag is borderline, consider packing lighter or choosing a smaller bag. It is cheaper and less stressful than dealing with overweight or oversized bag fees at the airport.

Frequently Asked Questions

Do I measure the inside or outside of my luggage?

Measure the outside. Airlines measure the exterior dimensions of the bag as it sits, including any wheels, handles, or pockets that stick out. The interior space does not matter for size limits.

What if my bag is slightly over the size limit?

If it is only an inch or two over, it might still fit in the overhead bin or pass inspection at check-in, depending on the airline and how full the bin is. But there is no may provide. If you know it is over, contact the airline before you travel or choose a smaller bag to avoid fees or delays.

Can I measure my luggage in centimeters instead of inches?

Yes. Most airlines accept measurements in either unit. Just make sure you convert correctly: 1 inch equals 2.54 centimeters. If the airline lists a limit in inches, convert your centimeter measurement to inches before you compare.

Do wheels and handles count toward the size limit?

Yes. Measure around them. The airline measures the bag as it actually sits, not a theoretical bag without wheels or handles. Include any protruding parts in your length, width, and depth measurements.

How do I measure a bag with an irregular shape?

Measure at the widest point in each direction. For a bag that tapers or has curved sides, find where it bulges the most and measure there. This gives you the true size the bag will take up in the overhead bin or cargo hold.