Backpack size guide: what fits in 20L, 25L, 30L and 40L.
Choose the size by your longest regular trip, not your average day. 20 litres carries a laptop and a day's essentials. 25 litres adds a layer and a water bottle. 30 litres covers a gym kit or a two-night trip. 40 litres is for longer trips with one carry-on bag. Black Ember makes a pack at each size: the CITADEL R3 20, CITADEL R3 25, FORGE 30 and FORGE 40.
What size backpack do you need?
Twenty-five litres fits a 16-inch laptop and a 13-inch tablet in separate sleeves, with room for a layer and a water bottle. Load lifters and an air-channel back panel carry it all day.
What fits in a 20L, 25L, 30L and 40L backpack?
Not a backpack person? At 20 litres the FORGE SB ($245) carries a 16-inch laptop as a soft brief and shoulder bag, and the WPT SHLDR TOTE ($245) carries one as a tote or crossbody.
Between two sizes? Choose a pack that expands.
A 20-litre daily pack that opens to 30 for a gym kit or a two-night work trip. Carries three ways: backpack, soft brief and shoulder bag.
A 30-litre travel pack that opens to 40 for longer trips, with a top pocket made for the BOARDING KIT and an optional hip belt ($25).
Both are sized for carry-on and fit the overhead bin of major airlines; a few budget European airlines with unique size limits are the exception.
How big is each backpack, in inches?
Figures from blackember.com product pages. List prices checked November 12, 2026. All packs: EmberTex™ PFAS-free shell, YKK® AquaGuard® zippers, lifetime guarantee. One litre is about a 4-inch cube.
What size backpack do I need?
Choose by your longest regular trip. 20 litres for a workday with a laptop, 25 litres for a full day with a 16-inch laptop, a layer and a water bottle, 30 litres for a gym kit or a two-night trip, and 40 litres for longer trips with one bag.
How big is a 20L backpack?
The CITADEL R3 20 measures 17 × 12 × 6.7 in (44 × 30 × 17 cm) and weighs 2.75 lb. It holds a 14-inch laptop in a suspended sleeve, a 13-inch tablet, a charger, a notebook and lunch.
Is a 25L backpack big enough for every day?
Yes, for most commutes. The CITADEL R3 25 (20 × 12 × 7 in) fits a 16-inch laptop and a 13-inch tablet in separate sleeves, with room for a layer and a water bottle.
What size backpack do I need for a two-night trip?
About 30 litres. The FORGE 30 expands from 20 to 30 litres, carries a 16-inch laptop, and is sized for carry-on. For longer trips, step up to the FORGE 40.
Is a 30L backpack carry-on size?
It depends on the dimensions, not the litres. The FORGE 30 measures 18 × 12 × 8 in compressed and 18 × 12 × 10 in expanded, is sized for carry-on, and fits the overhead bin of major airlines; a few budget European airlines with unique size limits are the exception.
Is a 40L backpack carry-on size?
Not every 40-litre pack is; the dimensions decide. The FORGE 40 measures 20 × 12 × 8 in compressed and 20 × 12 × 10 in expanded, is sized for carry-on, and fits the overhead bin of major airlines; a few budget European airlines with unique size limits are the exception.
Which backpack size fits a 16-inch laptop?
The CITADEL R3 25, FORGE 30 and FORGE 40 all carry a 16-inch laptop and a 13-inch tablet. The 20-litre CITADEL R3 20 fits a 14-inch laptop.
Are Black Ember backpacks waterproof?
No. They are weatherproof: waterproof performance textiles (EmberTex™) and YKK® AquaGuard® reverse coil zippers make a build that is highly water resistant, designed to keep your gear dry during a typical commute in bad weather. They are not waterproof, watertight, or dry bags.
