Michael Turner
Choose ~25 L for everyday school or city carry. Compact options at 15–18 L suit a tablet, wallet and light jacket; standard student designs around 25 L fit a 15″ laptop, two textbooks and a lunchbox; commuter models of 28–32 L hold a laptop, gym shoes and a water bottle; day-trip or carry-on choices of 40–50 L take extra clothing and toiletries.
Convert external dimensions to volume by multiplying length × width × depth in centimeters and dividing by 1,000. Example: 45 cm × 30 cm × 20 cm = 27,000 cm³ → 27 L. Measure the main compartment only; allow an extra 2–4 L for external pockets, a padded sleeve and internal organizers.
Selection guidance: 15–18 L for children and minimalists; 20–28 L for students and light commuters; 30–35 L for users who carry larger laptops plus gym gear; >40 L for short overnight trips. Check sleeve dimensions – a 15″ sleeve typically reduces usable capacity by ~3 L.
Packing tips: place heavy items low and close to the back panel for better balance, use compression straps to limit shifting and make room, and compare volume units carefully – divide cubic inches by 61 to get L (1,700 in³ ≈ 28 L).
Choose around 25–34 L for daily use; pick 35 L or more for overnight trips.
25 L models handle a 15″ laptop, one or two notebooks, a water bottle and lunch; 30–34 L units add room for extra textbooks, a light jacket and gym shoes; 35–50 L suits multi-day packing or carry-on with bulkier clothing.
Typical volumes (approx.)
- Small daypacks: 15–22 L (915–1,344 cu in / 4–5.8 gal)
- Everyday/school: 25 L (1,526 cu in / 6.6 gal) – common classic size
- Larger student/commuter: 30–34 L (1,831–2,075 cu in / 7.9–9.0 gal)
- Travel/overnight: 35–50 L (2,136–3,051 cu in / 9.2–13.2 gal)
Capacity guide & sample loads
- 15–20 L: phone, slim tablet, wallet, keys, light jacket – best for quick outings.
- 25 L: 15″ laptop in padded sleeve, 1–2 notebooks, lunchbox, 1L water bottle, small umbrella.
- 30–34 L: 15″ laptop, 3 textbooks, folder, lunch, sneakers, toiletry kit – good for full school days.
- 35–50 L: 2–3 days of clothing, toiletries, shoes and a compact packing cube – suitable for short trips.
If you need a single recommended number for daily carry, target 30 L; increase to 40+ L when packing clothes or gear for overnight use.
Typical capacities for SuperBreak, Right Pack, Big Student
Recommendation: SuperBreak – ~25 L for light daily carry and a slim profile; Right Pack – ~31 L for schoolbooks plus a 15″ laptop; Big Student – ~34 L for heavy school loads, sports kit, or short overnight packing.
Model breakdown
SuperBreak – Capacity: ≈25 L. Dimensions: ~42 x 33 x 22 cm (16.5″ x 13″ x 8.5″). Weight: ~0.3–0.5 kg. Features: single main compartment, front utility pocket, minimal internal organization. Best for: commuting with a tablet, lunch, and light extras; fits a compact 13″ device in sleeve or sleeve sleeve add-on.
Right Pack – Capacity: ≈31 L. Dimensions: ~43 x 33 x 24 cm (17″ x 13″ x 9.5″). Weight: ~0.6–0.8 kg. Features: padded laptop sleeve (fits up to 15″), suede-leather bottom, larger front organizer pocket. Best for: students carrying textbooks, a 15″ laptop, binder, water bottle and lunch.
Big Student – Capacity: ≈34 L. Dimensions: ~48 x 33 x 23 cm (19″ x 13″ x 9″). Weight: ~0.7–0.9 kg. Features: oversized main compartment, dedicated padded laptop sleeve (up to 15–17″), two large front pockets, reinforced straps. Best for: heavier loads, gym gear plus school supplies, or short overnight use.
Quick selection tips
Pick ~25 L for light everyday carry, ~31 L for full school load with a 15″ device, ~34 L when needing extra room for sports gear or multi-day essentials. If you carry a larger laptop or multiple textbooks, choose the larger model; if commuting light, choose the smaller model for lower weight and slimmer fit.
Measure pack capacity at home and convert to L
Recommendation: use geometric measurement for structured models and volume-displacement with dry grains for soft, collapsible ones; convert cubic centimetres to L by dividing by 1,000 (1 L = 1,000 cm³).
Geometric method: open the main compartment, measure internal height (H), maximum internal width (W) and maximum internal depth (D) in centimetres. Calculate Volume (cm³) = H × W × D. Example: H 40 cm × W 30 cm × D 15 cm = 18,000 cm³ → 18 L. Measure secondary pockets separately and add results.
Tapered or irregular shapes: take three width measurements (top, middle, bottom) and three depth measurements, average them (Wavg = (W1+W2+W3)/3, Davg likewise) and use H × Wavg × Davg. For a conical taper, multiply the product by ~0.7 to approximate the tapering effect.
Displacement method for soft fabric: place the empty pouch inside a large, leakproof bag; fill the pouch with dry rice or small beads until fully shaped; pour contents into a graduated measuring jug to read cm³ or mL (mL ≈ cm³). Use a scale if no jug: weigh rice (density varies) and convert using package density label; prefer direct volume measurement for accuracy.
Precision tips: measure internal space without compression; ignore foam padding thickness unless it limits usable volume; include hip-belt pockets and external sacks as separate additions. Expect geometric arithmetic to be accurate within ±5–10%; displacement with rice typically within ±2–5%.
Conversion quick-reference: cm³ ÷ 1,000 = L; round to the nearest whole number for casual use, or to one decimal for gear comparisons (e.g., 18,300 cm³ → 18.3 L).
If you want an unrelated appliance measurement example or a household reference, see are samsung american style fridge freezer any goodr.
Converting cubic inches to L: quick formulas
Exact formulas
Use the exact conversion factor 1 in³ = 0.016387064 L. Multiply the cubic-inch value by 0.016387064 to get volume in L.
V (L) = V (in³) × 0.016387064
Inverse: V (in³) = V (L) × 61.0237441
Quick estimates and examples
Fast approximations: multiply by 0.0164 for a near-exact result (error ≈ +0.8%), or divide cubic inches by 61 for a simple mental estimate.
Examples: 1,000 in³ → 16.387 L (≈16.4 L); 1,250 in³ → 20.484 L (≈20.5 L); 1,500 in³ → 24.581 L (≈24.6 L); 2,000 in³ → 32.774 L (≈32.8 L).
Rounding guidance: use one decimal for consumer comparisons (e.g., 24.6 L), two decimals for specification sheets, and whole numbers only for very large volumes or casual mentions. For soft-sided items expect ±5–10% variance between measured external volume and usable internal capacity; apply the same conversion factor to either figure.
Choose a 25–30 L model for secondary school/campus; 15–20 L for elementary; 20–28 L for daily commuting with a laptop; 30–40 L for full-day hikes with extra layers and food.
Match capacity to load rather than style: laptop + textbooks = 25–30 L; laptop only + lunch = 18–22 L; water, snacks, jacket, camera = 28–35 L. For child users keep packed weight below 10–12% of body mass; for adults aim under 15% for all-day comfort.
Capacity guidance table
| Use case | Recommended capacity (L) | Typical contents | Key selection note |
|---|---|---|---|
| Elementary school | 15–18 L | Small lunchbox, pencil case, light jacket, folder | Smaller torso fit, padded straps, no heavy laptop |
| Middle / high school | 22–30 L | Several textbooks, binder, 13–15″ laptop, water bottle | Look for internal organizer and reinforced base |
| College / daily commuter | 20–28 L | 15″ laptop, charger, notebook, gym clothes, lunch | Dedicated laptop sleeve, quick-access pocket for transit items |
| Cycling / multi-modal commuter | 18–26 L | Compact rain shell, tools, lock, 13–15″ laptop | Reflective details, sternum strap, hip-belt optional |
| Short day hike (4–6 hrs) | 28–35 L | 2 L water bladder, lunch, warm layer, first-aid, camera | Hydration-compatible sleeve and external lash points |
| Long day hike (all day) | 35–40 L | Extra insulation, larger food supply, rain shell, stove basics | Padded hip belt and load lifters recommended |
Features and packing strategy
Prioritize these attributes: a padded laptop sleeve sized for a 15″ device (approx. 38×26 cm), a hydration sleeve that accepts a 2 L reservoir, dual water bottle pockets, compression straps to reduce swing, and a reinforced base for durability. For loads above ~28 L choose a model with a padded hip belt and adjustable sternum strap to transfer weight away from shoulders.
Packing order: heavy items close to the back and centered, medium items below, soft items or jacket at top or in external pocket for quick access. Use small internal organizers or packing cubes for chargers, pens, and masks to avoid rummaging during class or transit.
For wet climates include a rain cover or choose water-resistant fabric; pair the pack with a compact umbrella such as the best umbrella in germany for added protection on rainy commutes.
Understanding labeled capacity vs usable L: pockets, laptop sleeves and shape
Quick rule: subtract 10–25% from the stamped capacity to estimate actual packable volume in L; use 20–25% for laptop-carrying commuter rigs and 10–15% for minimalist, single-compartment designs.
Manufacturers usually state total internal volume including sleeves, pockets and small zippered compartments. That figure overstates flexible packing room because padded laptop sleeves and fixed organizers remove compressible space and limit how items nest. Typical volume draws:
Common internal volumetric draws (approximate): laptop sleeve = 1–3 L (13″ ≈ 1 L, 15″ ≈ 2 L, 17″ ≈ 3 L); front/quick-access pockets = 0.5–2 L; pen/phone organizers and mesh dividers = 0.2–0.8 L; rigid tablet bay or frame = 0.5–2 L.
Shape inefficiency: round, tapered or curved silhouettes create voids and dead corners. Expect an additional 5–15% usable loss for cylindrical or teardrop shapes vs rectangular boxes. Padding and internal structure commonly account for another 2–6 L on mid-size packs.
Use this calculation to convert label → realistic packing space:
Usable_L = Labeled_L − Sleeve_L − Pocket_L − Shape_Loss
Example: labeled 25 L commuter with a 15″ sleeve (2 L) and front pockets (1.5 L) and 10% shape loss → usable = 25 − 2 − 1.5 − 2.5 = 19 L of flexible packing room.
Packing recommendations by use case:
School / Campus: choose a rectangular main compartment and an external sleeve; subtract ~15% and plan for 2–3 L taken by organizers. Prefer models with full-width zip for easy access to textbooks.
Commute with laptop: expect 20–25% reduction; pick a removable or external sleeve if you need the full internal volume for non-electronics days.
Day hikes / travel: if clothing compression matters, favor boxy profiles and minimal internal dividers; compression straps can regain 1–3 L by reducing air gaps.
Practical checks before purchase: unzip and physically test fit a folded set of items you normally carry (laptop, water bottle, jacket, notebook). If you cannot fit that test load with a small margin, the labeled L overpromises for your use. For travel-oriented comparisons see best luggage to take to bali.
FAQ:
How many liters does a JanSport SuperBreak backpack hold?
The JanSport SuperBreak is commonly listed at about 25 liters. That capacity is enough for a few textbooks, a light sweater, a small tablet or a 13″ laptop (depending on sleeve), and a water bottle in the side pocket. Keep in mind capacity figures refer to internal volume; external pockets add some carrying room but do not greatly change the stated liter value.
How can I measure my JanSport backpack’s capacity in liters if the model doesn’t show it?
Measure the main compartment’s maximum internal length, width and depth in centimeters (ignore external straps and flat pockets). Multiply those three numbers to get cubic centimeters, then divide by 1000 to convert to liters (example: 45 cm × 30 cm × 20 cm = 27,000 cm³ → 27 L). Because backpacks are rarely perfect boxes, reduce that result by about 10–25% to estimate usable space for rounded shapes and seams. Add separately the approximate volume of large external pockets (measure each pocket the same way) and combine totals for an overall estimate. If you prefer not to measure, check the product page or tag, or compare visually to a model with a known liter rating (for example, JanSport Right Pack models are commonly around 30–32 L and SuperBreak about 25 L).
