Compression bags and suitcases are made for each other in one obvious way: a suitcase is a box, and a compressed bag is a flat slab that stacks neatly inside a box. In practice, though, most people buy a set of compression bags without looking at the suitcase they will go into. The large bag turns out to be too long for the carry-on, the slabs wobble on the bumps of the handle channel, and the case that now closes easily weighs 27 kg at check-in.
This guide works the other way round, starting from the suitcase. It explains how to match bag sizes to carry-on, medium and large cases, how hard-shell and soft-sided luggage change the packing, where in the case the compressed bags should go, and how to keep a fuller suitcase inside the airline's weight limit. It is written for travellers and for luggage and travel brands, and draws on over 20 years, since 2001, of making welded travel compression bags and waterproof travel bags at our factories in Dongguan, China and Ho Chi Minh City, Vietnam.
Start With the Inside of the Suitcase
The size printed on a suitcase is the outside size, including wheels and handle. The space you can actually fill is smaller, and a compressed bag needs to lie in that space without bending. A bent compressed bag puts strain on its seams and valve, and on a suitcase it also pushes against the lid and the zipper. Before buying compression bags, open your suitcase and measure the floor of the packing space, from the wheel end to the handle end and from side to side, and note how deep each half is.
Look at the floor while you are there. Most wheeled suitcases have two raised channels where the trolley handle runs underneath. A compressed bag laid straight onto those ridges rocks and leaves gaps either side. Fill the low areas between the channels with socks, a belt or a charger pouch first, so the compression bags sit on a level base.
Carry-On, Medium or Large: Which Bag Sizes Fit
A typical carry-on suitcase is around 22 × 14 × 9 inches (about 56 × 36 × 23 cm) on the outside. Inside, the packing floor is usually somewhere near 48 to 50 cm long and 32 to 34 cm wide. Bags up to about 48 × 31 cm lie flat in it: in our range that means the small and medium roll-up bags (38 × 27 cm and 46.5 × 31.5 cm), the hand-pump bag (48 × 29 cm) and the built-in-pump bag (42 × 29 cm). Two or three of these, stacked, usually fill one half of a carry-on.
Medium checked cases, around 24 to 26 inches tall, have a packing floor of roughly 58 to 63 cm by 38 to 42 cm. Here a large bag of 53.5 × 38.5 cm lies flat with room around it, and two medium bags fit side by side across the width in some cases. Large checked cases of 28 to 30 inches take the large bag easily and can hold two large bags end to end in a deep half. As a rule of thumb, small and medium bags are for carry-ons, large bags are for checked cases, and a mixed set covers both. If your main bag is a duffel rather than a suitcase, the approach is different, and our guide to compression bags for duffel bags explains it.
| Suitcase | Typical outside size | Compression bag sizes that lie flat | Typical set |
|---|---|---|---|
| Carry-on | 20–22 in (51–56 cm) | Up to about 48 × 31 cm | 1 small + 2 medium, or 2 pump bags |
| Medium checked | 24–26 in (61–66 cm) | Up to about 55 × 40 cm | 1 large + 2 medium |
| Large checked | 28–30 in (71–76 cm) | Large bags, two end to end | 2 large + 1–2 medium |
Inside dimensions vary by brand and by shell shape, so measure your own case before choosing.
Hard-Shell or Soft-Sided: How the Case Changes the Packing
Most hard-shell suitcases open like a clamshell into two halves of similar depth, each closed by a zip-up panel or straps. Compression bags suit this layout well. Put the compressed bags in one half, where they stack into a flat, even block, and use the other half for things that should not be compressed: shirts and trousers that must not crease, shoes, a toiletry bag. Because a hard shell cannot bulge, the slabs also keep their shape and do not shift in transit. The thing to watch is the hinge: keep the edge of a compressed bag a finger's width away from it, so closing the case does not crush the bag's corner.
A soft-sided suitcase usually opens from the top into one deep compartment, often with an expansion zipper that adds a few centimetres of depth. Here compression bags do a different job. Packed flat in layers at the bottom, they give the case a firm floor and stop the sides from sagging, which helps the case stand up and keeps tailored clothes on top flatter. The main benefit is often that you never need to open the expansion zipper at all. An expanded case is heavier, can push you over size limits and puts more strain on the main zip, so packing the same clothes into a closed case is a gain in itself.
Where the Compressed Bags Go
A compressed bag of clothes is also the densest thing in most suitcases, so where it sits affects how the case rolls and stands. Put the heaviest compression bags at the wheel end of the case, so the weight sits low when the suitcase is upright. A case with its weight near the handle end tips forward when you let go of it, and pulls on your wrist when you wheel it. In a clamshell case, put the compressed half on the side that lies against your legs when you wheel it, which is usually the back half.
Keep the valve side of each bag facing up, towards the lid, so you can see whether a bag has softened and re-tighten it without unpacking; our guide on how to use vacuum bags explains how to seal each type so it stays flat. Keep shoes, belts with metal buckles and anything with a hook away from the bags, or wrapped, because a sharp edge pressed against a compressed bag for a whole flight is a common cause of punctures. If you are flying with hand luggage only, the liquids bag needs to stay at the top where you can lift it out at security; our guide to building a travel packing system shows how the toiletry bag and small pouches sit around the compression bags, and our guide to business travel packing covers a carry-on with a suit in it.
The Overweight Checked Bag Problem
Compression bags save space, not weight, and a suitcase is where that matters most. On most US airlines the standard economy checked bag limit is 50 lb (23 kg) and 62 linear inches (158 cm), the length, width and height added together. Some low-cost carriers set a lower limit of 40 lb (18 kg). A large 28- or 30-inch case packed solid with compressed clothes can pass 23 kg easily, because it now holds far more than it was designed for. Overweight fees are often higher than the cost of a second checked bag.
Carry-ons have the same problem on a smaller scale. Many airlines outside the US set a cabin weight limit of 7 to 10 kg, and a hard-shell carry-on can weigh 2.5 to 4 kg empty. Weigh the packed case at home with a luggage scale. If it is over, take clothes out rather than compressing harder. Our guide on whether vacuum bags are allowed on planes covers security checks and the battery rules for pump bags.
What About Suitcases With Built-In Vacuum Compression?
A few luggage brands now sell suitcases and travel backpacks with a vacuum chamber built into the case. They are a neat idea, but they come with trade-offs that separate compression bags do not have. The chamber is part of one bag, so the compression goes only where that suitcase goes. The case itself is heavier: reviewers of one such carry-on weighed it at over 10 lb (about 4.6 kg) empty, close to half of a 10 kg cabin allowance. The pump is usually a separate unit that has to be carried and charged. And a single chamber holds everything together, so clean clothes, dirty laundry and wet swimwear cannot be kept apart.
Separate compression bags move between a carry-on, a checked case and a duffel, can be split by clothing type or by clean and dirty, and are replaced cheaply if one is damaged. For a brand, they also sell at a lower price point than a new suitcase and work with any luggage the customer already owns. To choose between rolling, a hand pump and a built-in pump, see our comparison of travel vacuum bags with pump; if you are still deciding between compression bags and packing cubes for a suitcase, our comparison of vacuum bags vs packing cubes may help.
Compression Bags for Suitcases in Our Range
| Image | Model | Capacity | Dimensions (H × W × D) | Weight | Construction | Use |
|---|---|---|---|---|---|---|
|
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SL-P1082 Vacuum Compression Bag for Travel |
S about 14 L M about 20 L L about 33 L |
S 38 × 27 × 14 cm (15.0 × 10.6 × 5.5 in) M 46.5 × 31.5 × 14 cm (18.3 × 12.4 × 5.5 in) L 53.5 × 38.5 × 16 cm (21.1 × 15.2 × 6.3 in) |
0.15 kg (0.33 lb) | TPU laminate, high-frequency welded, sealed zipper, one-way valve; IPX6 | S and M for carry-ons, L for medium and large checked cases; nested retail sets |
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|
SL-P1133 Vacuum Compression Bag With Hand Pump | About 13.9 L | 48 × 29 × 10 cm (18.9 × 11.4 × 3.9 in) | 0.18 kg + 0.05 kg pump (0.51 lb) | TPU laminate, high-frequency welded, sealed zipper, screw-seal valve with silicone gasket, clear window | Lies flat in a carry-on; compresses to about 3–5 cm thick |
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SL-P1083 Vacuum Compression Bag With Built-In Pump | About 13.4 L | 42 × 29 × 11 cm (16.5 × 11.4 × 4.3 in) | 0.2 kg (0.44 lb) | TPU laminate, high-frequency welded, sealed zipper, USB-C pump with screw-down cap, auto stop | Carry-on; one-button recompression on the return leg |
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SL-P255 Waterproof Toiletry Bag With Window | About 5.2 L | 25 × 15.5 × 13.5 cm (9.8 × 6.1 × 5.3 in) | 0.15 kg (0.33 lb) | TPU laminate, high-frequency welded, sealed zipper, clear window; IPX6 | Add-on: sits in the uncompressed half, keeps leaks off clothes |
MOQ is 300 pieces for the hand-pump and built-in-pump bags and 500 for the roll-up set and toiletry bag, with samples in about 7–15 days and bulk production in about 30–45 days. For luggage brands, bag sizes can be developed to fit the inside of your own suitcase models exactly, with matching colours, printed size labels and a set packed in the suitcase at the factory. We make the compression bags on our high-frequency welding lines and sew travel bags on our own sewing lines, so a brand can develop luggage accessories and travel bags with one supplier. For what to check in any compression bag, see our guide to the best travel vacuum bags; for MOQ and production options, our OEM vacuum compression bag supplier guide.
How We Test Compression Bags for Luggage
Every order passes through IQC on incoming TPU laminate, zippers, valves and pump parts, IPQC during welding and assembly, and OQC on finished bags, with SGS or QIMA third-party inspection available on request. Welded seams are tested for tensile and bonding strength, especially at the corners, valve mounts and zipper ends that take the pressure of a closed suitcase lid. Finished bags go through a load test of 1,500+ cycles and a tensile and burst test for the tension an over-packed bag creates, and sealed zippers are opened and closed 3,000 times. Hardware is tested in salt spray, fabric for abrasion, and colour fastness and colour difference are checked across every size in a set. The roll-up bag and toiletry bag are verified with a heavy rain and water-jet test. Every compression bag then goes through our customer inspection procedure: unboxing, vacuum extraction, a 24-hour static rest and air-leak determination.
Frequently Asked Questions
How many compression bags do I need for a suitcase?
For a carry-on, two or three small or medium bags. For a medium checked case, one large and two medium bags. For a large checked case, two large bags and one or two medium bags. Leave some space for clothes that should not be compressed.
What size compression bag fits a carry-on suitcase?
Bags up to about 48 × 31 cm (19 × 12 in) lie flat in most carry-ons. Larger bags have to bend, which strains the bag and the suitcase lid.
Do compression bags make a suitcase heavier?
The bags themselves weigh only about 0.15 to 0.2 kg each, but they let you pack more, so the full case is heavier. Weigh it before you go; most US airlines allow 50 lb (23 kg) for a checked bag.
Can compression bags damage my suitcase?
No, if the case closes without force. They often reduce strain on a suitcase zipper, because the clothes no longer have to be pressed in. Do not use the space saved to over-fill the case.
What is the MOQ for custom compression bags for luggage?
300 pieces per style for the hand-pump and built-in-pump bags and 500 for the roll-up set. Custom sizes to fit your suitcases are available.
How much do custom compression bags cost?
It depends on the compression method, sizes, the number of bags per set, logo method, packaging and order quantity. Send us your suitcase dimensions and target quantity for a quotation.
Can you put our luggage brand's logo on the bags?
Yes, by silk screen, heat transfer, welded logo patch or custom zipper pull, with colours matched to your luggage and size labels printed on each bag.
Develop Compression Bags for Your Luggage
Send us the inside dimensions of your suitcases, or a sample case, and tell us which compression method you prefer. We will propose bag sizes that fit, make samples and plan production in China or Vietnam. Contact us at info@sealock.com.hk or call +86-769-82009361.