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What Fits in a 70L Dry Bag

What seventy litres means once the closure is rolled

Capacity printed on a hangtag describes the bag with the mouth fully open and the fabric standing straight. Nobody paddles with a bag in that state. Three folds of the closure remove between 5 and 8 litres from a 70L body depending on mouth diameter and how tightly you roll, so the planning figure is 62 litres, not 70. Four folds push the loss past 10 litres and add a hard crease that shortens film life by a season or two.

The second adjustment is shape loss. A bag that is only 70% full does not hold its cylinder, so the effective volume for a partial load is smaller than the geometric volume. Soft items such as a down bag or a fleece compress into corners; rigid items such as a pot set, a fuel bottle or a camera body leave voids you cannot use. On a mixed seven-day load, expect 8 to 12% of the remaining space to be unusable void, which lands the honest planning figure at 56 to 58 litres.

Work from 56 litres of real packing space and you will never be caught short at the put-in. Work from 70 litres and you will be re-packing in the rain. The rule that survives field use is simple: add 15% to your measured kit volume, then pick the size above the result, and check that the loaded bag still closes with three clean folds and a buckle that seats without force.

The 70L body in real dimensions

A 70L roll-top cylinder is typically 30 to 34 cm in diameter and 82 to 90 cm tall with the mouth rolled and the buckle closed. That height matters more than buyers expect: 88 cm will not lie flat across the floor of most estate cars, will not stand upright under a kayak deck, and will not pass through a narrow raft frame gap without being angled. A duffel-format 70L trades height for footprint at roughly 62 cm long, 30 cm wide and 34 cm deep, which fits a roof box and a canoe thwart far more easily.

Empty weight separates the formats as much as shape does. A plain cylinder with a 0.5 mm TPU film on a 500D face fabric and a single welded shoulder strap weighs 780 to 950 g. Add a padded harness, a compression system and four welded D-rings and the same volume reaches 1,300 to 1,550 g. That 600 g difference is real weight on a portage, and it is also the clearest signal of how much hardware the bag carries.

Where 70L sits in the size ladder

Between 60L and 80L there is one decision, and it is not about volume. A 60L pack covers four to five days for one person if you sleep light and resupply water. A 70L covers six to eight days, or a five-day trip with a camera kit, or a three-day trip for two people who share a shelter. An 80L is what you buy when the group carries one bag for a tent, one for food and one for clothing rather than when one person carries everything.

The jump from 50L to 70L is the one most paddlers get wrong in both directions. Buyers who camp in summer with a 0 °C bag and no stove often find 50L generous, then buy 70L for a colder trip and discover the winter bag plus a stove plus a fuel bottle fills it completely. Cold-weather kit volume grows faster than weight: a −5 °C synthetic bag takes 16 litres against 9 litres for a summer bag, and that single swap eats most of a 20L step.

There is a practical ceiling too. Above roughly 25 kg a single dry bag becomes unsafe to lift one-handed out of a hatch, and above 90 cm the bag will not sit inside most kayak compartments at all. If your load projects past 25 kg, split it into a 40L and a 30L rather than buying one 90L; two bags are easier to trim, easier to lash and give you redundancy if a closure is ever compromised. The volume comparison between dry bags and backpacks explains why the litre numbers are not interchangeable between the two categories.

Sleep systems that fit, and the ones that fight you

Sleep kit is the largest single block in a 70L bag and the block that decides whether the size works. A summer down bag packed in a compression sack takes 7 to 9 litres. A three-season synthetic bag takes 11 to 14 litres. A genuine −5 °C expedition bag takes 16 to 19 litres even compressed, and a −15 °C bag can reach 24 litres, which is a third of the usable space on its own.

Mattresses behave differently because they resist compression in one dimension. An inflatable pad packed tightly takes 3.5 to 5 litres; a self-inflating pad with open-cell foam inside takes 7 to 9 litres and never fully recovers its loft if stored compressed for months. A closed-cell foam pad is the awkward case: it takes 9 to 12 litres if packed inside, which is why almost every expedition paddler straps it to the outside of the bag instead and spends zero internal litres on it.

Treat the sleep block as fixed before you allocate anything else. Work out its litres first, subtract from 56 L of real packing space, and only then decide what is left for clothing, food and cooking. Buyers who shop in the other order — food first, shelter second, sleep last — are the ones who arrive with a bag that closes but bulges, which is exactly the condition that lets water into the fold.

Food, cooking and water for six to eight days

Food volume is the most predictable part of an expedition load and the easiest to plan with a table. A well-chosen ration of dehydrated meals, oats, nuts, dried fruit and chocolate delivers roughly 2,800 to 3,400 kcal per day in 1.3 to 1.7 litres and 0.7 to 0.9 kg. Multiply by seven days and you have 9 to 12 litres and 5 to 6.5 kg, before the stove, the fuel and the pot set that turn it into meals.

Water does not belong inside a dry bag. Two litres weighs 2 kg and occupies 2 litres of your most valuable space, and every hydration bladder ever packed into a dry bag has eventually leaked onto the food. Carry water in a rigid bottle lashed to the outside or in a dedicated liner, and spend the internal litres on calories instead. On a river trip where water is treated at camp, carry 1 L on the boat and filter 2 L at each stop.

A seven-day load, item by item

The load below is a real six-to-eight day paddle or raft trip for one person in cool, wet conditions: a three-season bag, a two-person tent shared with a partner who carries the poles and the fly, a stove, and no resupply. Volumes are packed as they actually sit, not compressed to a theoretical minimum, and weights include the stuff sacks that keep the load organised.

Notice that the sleep and shelter blocks consume 27 litres between them, which is about half the usable space, and that food is the second largest block at 12 litres. A camera kit, a dry suit or a second pair of shoes pushes the total past 62 litres and is the point at which most people either move to 80L or split the load. If your own list exceeds 60 litres, you are no longer shopping for a 70L bag.

That list totals 60 litres and 17.4 kg, which sits inside a 70L body with room for the void you will inevitably lose. Add a dry suit at 4 litres and 2.4 kg and you are at 64 litres, past the usable figure, and the correct answer is a second 20L bag lashed alongside rather than a bigger main bag. Splitting also lets you keep the suit, the towel and the wet shoes away from the sleep system.

Sharing one 70L bag between two people

Two paddlers sharing a 70L bag is the most common real-world use of the size, and it works well if the split is decided before packing. The usual arrangement is one person carrying the shelter and the cooking kit, the other carrying the sleep system and the clothing, with food divided by weight so both loads land within 2 kg of each other. A 70L bag holding both sleep systems at 30 litres plus shared clothing at 14 litres plus food at 12 litres comes to 56 litres and roughly 24 kg, which is a two-person lift.

The failure mode is the shared bag that nobody owns. If one person packs the bag and the other person assumes it is packed, items go missing and the closure gets rolled by whoever is closest, sometimes over a strap. Assign one bag owner per trip who rolls the closure, checks the buckle and confirms the lashing before launch, and the shared-bag system stops producing surprises on day four.

Colour coding earns its place here. Two people sharing one bag plus two personal 20L bags should run three different colourways so a bag can be identified at a glance in a wet camp, and the shared bag should carry a welded clear window or a reflective panel so it is visible on a dark raft frame. Our roll-top range uses one closure across every size, so a shared-bag system can be standardised without retraining anyone.

What a loaded 70L weighs and how far it can be carried

A full 70L bag weighs 17 to 22 kg on a summer expedition and 24 to 28 kg on a winter one. That range decides how you move it. At 18 kg a fit paddler can carry the bag 400 to 800 m on a flat portage with a shoulder strap before needing a rest. At 26 kg the same carry becomes a two-handed lift-and-shuffle of 150 to 250 m, and the limiting factor stops being fitness and starts being grip and the strain on the welded handle.

Weight also decides where the bag may travel on the water. A 22 kg bag in a sea kayak rear hatch is fine and helps trim. The same bag lashed to a front deck is not: it lifts the bow, makes the boat weathercock, and if it shifts in a wave it changes the handling of the boat at the worst possible moment. The working rule is 1.5 kg maximum forward of the cockpit, and everything else central or aft and tethered to a fixed point.

• Weigh the loaded bag on a luggage scale before a trip; if it exceeds 22 kg, split it into two bags.
• Carry a 70L by the welded side handle and a shoulder strap together, not by the closure buckle.
• Keep 1.5 kg or less forward of the cockpit and lash with two lines and one full turn.
• On a raft, place the bag against a frame crossbar so wave impact loads the frame, not the film.
• On a roof rack, lay the bag flat and strap over the body, never over the rolled closure.

Film, seam and hardware spec at this volume

Volume changes the specification, not just the size. A 70L bag carries two to three times the load of a 20L bag, so the film sees higher stress at the base seam and the welded handles work harder on every lift. The practical minimum is a 0.5 mm TPU film laminated to a 420D or 500D face fabric; a 0.3 mm film that is perfectly adequate on a 5L deck bag will creep and eventually tear at the base weld of a bag carrying 22 kg.

Seam construction matters more than film thickness at this size. The base seam on a cylinder takes the entire load when the bag is lifted by its shoulder strap, so it should be a continuous radio-frequency weld with no stitching and no seam tape. Ask for the peel strength figure in newtons per 25 mm and the hydrostatic head rating of the assembled bag, both of which are measured under published test methods maintained by the ISO.

Hardware is the third leg. At 22 kg a welded D-ring should be rated well above the load it sees; a lash point that pulls off a loaded bag on a portage is a genuine hazard, not a warranty claim. Look for welded D-rings on load-bearing points, a buckle with a rated breaking strength printed on the spec sheet, and a shoulder strap that is welded rather than sewn at both ends. The failure ranking is consistent across returned bags: lash points first, buckles second, film third.

Boat, rack and vehicle fit for a bag this tall

Before you buy, measure the space the bag has to occupy. An 88 cm cylinder will not lie across the boot floor of a compact car, will not stand under a sit-on-top deck, and needs to be angled through a 60 cm raft frame gap. A duffel-format 70L at 62 cm long solves all three and is the format to choose when the bag spends more time in vehicles and rafts than inside a kayak hatch.

On a kayak, the constraint is the hatch aperture rather than the volume. Most sea kayak day hatches accept a 30 cm diameter bag; many do not accept 34 cm. Measure the hatch opening, subtract 2 cm for the bag to slide, and buy to that number. If the bag has to deform to enter the hatch, it will also fight you when it is wet and heavy, which is when a torn seam usually happens.

On a roof rack or a raft frame, strap over the body of the bag and not over the rolled closure. Pressure on the closure compresses the fold and, on a long highway day at 100 km/h with a wet bag, will work water into the seam. Two cam straps at a third and two-thirds of the bag length, tightened until the bag cannot rotate, is the standard lashing and it takes about forty seconds.

Packing order that keeps a tall load stable

A 70L cylinder is tall and narrow, which means a badly packed one becomes top-heavy and tips over in camp. Heavy, dense items go at the bottom: food, cooking kit, fuel outside the bag, tools. Mid-weight soft items go in the middle: clothing, towel, sleeping bag. Light bulky items go on top: the inflatable pad, the dry suit, the pillow. Anything you need at lunch goes in the last 10 cm below the closure, not at the bottom.

Fill the corners before you fill the centre. A cylinder packs badly if you drop one large soft item into the middle and push everything around it; instead, place items around the wall of the bag first and work inward. Press each layer down before adding the next, and stop at roughly 85% of the geometric volume so the closure has fabric left to fold. An over-filled bag cannot make three clean folds, and two folds is not enough for anything more than spray.

Finish by purging air. Press the bag down with a knee, squeeze the air out through the mouth, then make the first fold. Trapped air makes the bag buoyant in a way that changes how it sits on a deck, and it pushes against the fold from inside as the bag warms in the sun. The physics of that pressure is set out in our guide to air traps inside dry bags, and the volume arithmetic of the fold itself is covered in the capacity loss guide.

When seventy litres is the wrong size

There are three cases where 70L is the wrong purchase. The first is the summer weekend paddler: a 40L bag holds a summer sleep system, two days of food and a change of clothes with room to spare, and a 70L bag in that use is 900 g of dead weight and a great deal of air to purge on every pack. The second is the kayak tourer with small hatches, where a 70L cylinder simply will not enter the boat and two 30L bags are faster to load.

The third case is the photographer or the expedition paddler carrying genuinely bulky kit. A camera body with two lenses, a dry suit and a seven-day food load exceeds 70 litres comfortably, and the correct answer is not a bigger single bag but a system: one 70L for the camp and one 25L for the fragile items. Splitting protects the camera from the fuel bottle and gives you a bag you can open on deck without unpacking the whole trip.

If you are deciding between 60L and 70L, weigh the winter question. If any trip on your calendar needs a −5 °C bag or a dry suit, buy the 70L and accept 400 g of extra empty weight. If every trip on your calendar is between May and September, buy the 60L, save the weight and spend the money on a better pad. The neighbouring sizes are compared in detail in the 60L guide and the 80L guide.

Spec checklist before you commit to 70L

• Measure your real kit volume and add 15%; buy the size above the result, not the size that matches it.
• Plan on 62 usable litres for a 70L bag and 56 litres once void loss is counted.
• Check the format against the space it must occupy: 88 cm tall or 62 cm long, measure first.
• Specify 0.5 mm TPU film on 420D or 500D face fabric; 0.3 mm is not enough at 22 kg.
• Require a continuous welded base seam with a peel strength figure in N per 25 mm.
• Insist on welded D-rings and a rated buckle; lash points fail before film does.
• Weigh the loaded bag; split the load at 22 kg rather than buying a bigger bag.
• Compare the shortlist against the full product line before ordering.

For a club fleet, a rental operation or a retail range, the same checklist becomes the purchasing brief, and the five lines that matter most are usable volume, film thickness, seam construction, hardware rating and the test standard behind the waterproof claim. Our production partner has built waterproof bags since 2014 in an SGS-verified 4,950 m2 facility with seven lines and a 200,000-piece monthly output, with a 500-piece minimum, sampling in 6 to 10 working days and bulk in 35 to 50 days from FOB Xiamen.

Two final checks are worth the time on any large bag. Confirm how the volume was measured, because a wet-fold method and a dry-fold method give different litre figures for the same body, and our capacity measurement guide sets out both. Then read the weather window for your trip window through NOAA if you paddle in US waters, because a seven-day plan built on 62 litres assumes you will not have to carry a wet tent for four of those days.