What size storage unit do I need? Pick your belongings from 120 typical household items — get an honest cubic-foot estimate with a 10–20% stacking buffer, the smallest standard unit that fits (5×5 to 10×30), a stacking plan, and climate-control advice. Independent tool: not owned by any storage company.
Volumes are honest typical estimates from standard dimensions (e.g. a 3-seat sofa ≈ 63 ft³). Measure your own big pieces if you want a tighter estimate.
Covers stacking gaps and a walkway aisle. Tight packers use 10%; loose stacking or odd shapes use 20%.
| Unit | Floor area | Usable volume* | Typical contents |
|---|---|---|---|
| 5 × 5 | 25 sq ft | 180 ft³ | Closet contents — dresser, twin mattress set, ~20 boxes |
| 5 × 10 | 50 sq ft | 360 ft³ | Studio overflow — queen mattress set, loveseat, ~30 boxes; or motorcycle + gear |
| 10 × 10 | 100 sq ft | 720 ft³ | Full 1-bedroom apartment |
| 10 × 15 | 150 sq ft | 1080 ft³ | 2-bedroom apartment |
| 10 × 20 | 200 sq ft | 1440 ft³ | 3-bedroom apartment, or a sedan |
| 10 × 30 | 300 sq ft | 2160 ft³ | 4–5 bedroom house |
* Usable = W × D × 8 ft ceiling × 0.90 (10% kept for the door swing, gaps and an access aisle). The method is fully transparent — nothing hidden.
Load heavy, sturdy items first against the back wall; fragile and light items ride on top. The plan below is generated from your inventory.
Tips: stand mattresses and sofas on end along the walls; fill hollow furniture (dressers, washers) with soft items; keep a center aisle so you can reach the back.
Climate-controlled units typically hold 55–85°F (13–29°C) and 30–50% relative humidity — the range that protects wood, electronics, leather, mattresses and paper from warping, mold and corrosion.
Storing a vehicle instead of (or as well as) household goods? Pick the type — boats and RVs need a length.
Vehicle storage is usually drive-up access; confirm door height/width with the facility (boats on trailers and tall RVs often need outdoor or covered RV parking instead).
Worked example from this calculator: a typical 1-bedroom inventory (queen bed set, 3-seat sofa, dining set, desk, TV, 25 moving boxes and small items) totals 514 ft³ of typical item volume. Add the default 15% stacking buffer → 591.1 ft³ adjusted. A 10×10 unit (8 ft ceiling, 90% usable) offers 720 ft³ — the smallest standard size that covers it, and the longest item (7 ft sofa) fits along the 10 ft wall. In general: 5×10 ≈ studio overflow, 10×10 ≈ 1 bedroom, 10×15 ≈ 2 bedrooms, 10×20 ≈ 3 bedrooms or a car, 10×30 ≈ a 4–5 bedroom house.
Fully transparent method: (1) total ft³ = sum of each item's typical volume × quantity (a 3-seat sofa ≈ 63 ft³, a king mattress ≈ 42.2 ft³, a dishes box ≈ 3.375 ft³); (2) adjusted = total × (1 + buffer%), with the buffer editable from 10–20% (default 15%); (3) usable unit volume = width × depth × 8 ft ceiling × 0.90 (10% reserved for the door swing, stacking gaps and an access aisle); (4) we recommend the smallest standard unit (5×5, 5×10, 10×10, 10×15, 10×20, 10×30) whose usable volume covers the adjusted total AND whose longest wall fits your longest item — e.g. a 87 ft³ studio (100.05 ft³ adjusted) fits a 5×5 by volume but the 7 ft sofa forces a bump up to 5×10.
Usable volumes (W × D × 8 ft × 0.90): 5×5 = 180 ft³ — closet contents (dresser, twin mattress set, ~20 boxes); 5×10 = 360 ft³ — studio overflow (queen mattress set, loveseat, ~30 boxes) or a motorcycle plus gear; 10×10 = 720 ft³ — a full 1-bedroom apartment; 10×15 = 1080 ft³ — a 2-bedroom; 10×20 = 1440 ft³ — a 3-bedroom or a sedan; 10×30 = 2160 ft³ — a 4–5 bedroom house. These are typical contents, not guarantees — run your own inventory above for the exact recommendation.
Box volumes never pack perfectly: furniture has hollow spaces, odd shapes leave gaps, and you need a walkway to reach the back. For the 1-bedroom example (514 ft³), a 10% buffer gives 565.4 ft³ while 20% gives 616.8 ft³ — a 51.4 ft³ swing that can change the recommended unit. Use 10% if you pack tightly with uniform boxes, 20% for bulky furniture and loose stacking. The buffer is editable in the calculator, never hidden.
Get climate control if you store any of these: electronics (TV, computers, monitors, printers), mattresses & upholstery (mold / mildew risk). Climate-controlled units typically hold 55–85°F (13–29°C) and 30–50% relative humidity — the range that prevents wood warping, mattress mildew, leather mold, electronic corrosion, and photo/document damage. If your inventory is only metal, plastic, and sealed boxes (like our no-climate test set: fridge + moving boxes), a standard drive-up unit is fine and cheaper.
Heavy and sturdy on the bottom, fragile and light on top — the calculator generates this plan from your inventory automatically. Rules: appliances, book boxes and dressers form the base layer; medium boxes and furniture fill the middle; dishes, mirrors, lamps and artwork ride on top. Stand mattresses and sofas on end along the walls, fill hollow furniture with soft items, and keep a center aisle. Never stack anything heavy on a mattress, TV, or glass-top table.
Motorcycle/scooter → 5×10 (most bikes are 7–8 ft long — too long for a 5×5). Sedan → 10×20 (~15 ft car with room to open doors); SUV/pickup → 10×20 as well (measure first if over 19 ft). Boat: we add 2 ft of walking room to the boat length — an 18 ft boat needs 20 ft of depth → 10×20. Boats over 28 ft (and RVs over 28 ft) don't fit standard units; most facilities only offer outdoor or covered RV parking for those. Use the Vehicle tab for the exact recommendation.
Different job, same move. This page answers 'what size rental unit do I need?' from an item inventory with cubic-foot math. Our moving cost calculator estimates what the move itself costs (distance, crew, truck), and the moving truck lab sizes the truck that carries the same inventory in one trip. Unlike the size widgets on storage-company sites — which exist to capture your contact details and nudge you toward their brand — this calculator is independent: the full method is disclosed above and no company is favored.
Total ft³ = Σ (typical item volume × quantity). Adjusted = total × (1 + buffer%), buffer 10–20% (default 15%). Unit usable volume = W × D × 8 ft × 0.90. Recommendation = smallest standard unit (5×5, 5×10, 10×10, 10×15, 10×20, 10×30) whose usable volume covers the adjusted total AND whose longest wall fits your longest item. Item dimensions are labeled "typical" estimates, not manufacturer specs.
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