Storage Unit Sizes: Complete Dimensions Guide

Storage unit sizes range from small 5x5 units to large 10x20 and bigger. This guide compares standard dimensions, square footage, and capacity to help you choose the right size for your belongings.

Standard Storage Unit Sizes

Self storage units are measured by width and depth. Ceiling height is typically 8 feet.

Unit Size Dimensions (W x D x H ft) Square Feet Comparable To
5 x 5 5 x 5 x 8 / 1.5 x 1.5 x 2.4 m 25 sq ft Walk-in closet or small bedroom closet
5 x 10 5 x 10 x 8 / 1.5 x 3 x 2.4 m 50 sq ft Half of a standard garage
10 x 10 10 x 10 x 8 / 3 x 3 x 2.4 m 100 sq ft Standard one car garage
10 x 15 10 x 15 x 8 / 3 x 4.6 x 2.4 m 150 sq ft Large bedroom
10 x 20 10 x 20 x 8 / 3 x 6.1 x 2.4 m 200 sq ft One car garage plus extra space
10 x 25 10 x 25 x 8 / 3 x 7.6 x 2.4 m 250 sq ft Two car garage
10 x 30 10 x 30 x 8 / 3 x 9.1 x 2.4 m 300 sq ft Large two car garage

Storage Unit Capacity by Size

Typical items that fit in each storage unit size for reference.

Unit Size Fits Contents Of Example Items
5 x 5 Small closet Boxes, seasonal items, small furniture
5 x 10 One bedroom apartment Mattress set, dresser, boxes, small appliances
10 x 10 Two bedroom apartment Full apartment furniture, appliances, boxes
10 x 15 Three bedroom house House furniture, appliances, patio items
10 x 20 Four bedroom house Entire house contents plus vehicle
10 x 25 Five bedroom house Large house plus garage items
10 x 30 Large home or commercial Multiple vehicles, business inventory

Climate Controlled vs Standard Units

Unit types and their features affect pricing and suitability for different items.

Unit Type Temperature Range Best For
Standard Outdoor Outside temperature Tools, vehicles, non-sensitive items
Climate Controlled 55 to 85 F / 13 to 29 C Electronics, wood, fabric, documents
Indoor Drive-Up Partially controlled Easy access with some protection

Visual Size Comparison

Storage unit size comparison from small to large.

Storage unit size comparison 5x5 10x10 10x20

Storage Unit Size Calculator

Find the right storage unit size based on your needs.

How to size a storage unit

Cubic feet, not just floor area

Storage units are sized by floor area, but capacity is the cube. A 5″×10″×8″ unit holds 400 cubic feet — about a small bedroom. A 10″×10″ holds 800 cu ft (a one-bedroom). A 10″×20″ holds 1,600 cu ft (a 2–3 bedroom home). Climbing the stack uses overhead room that's otherwise wasted.

Match the size to the contents

5×5: closet contents, seasonal items. 5×10: studio apartment + small furniture. 10×10: 1-bedroom apartment with mid-size furniture. 10×15: 2-bedroom apartment. 10×20: 3–4 bedroom home. 10×30: full home + vehicles.

Access matters

A bigger size is only useful if you can reach what you put in it. Leave a centre aisle when packing the unit so you can reach the back wall. Label boxes on multiple sides. The back third of any unit you can't walk into becomes effectively inaccessible — whatever lives there gets forgotten.

Common mistakes

  • Picking by floor area when volume is the real constraint.
  • Stacking dense items at the back of a long unit and never being able to reach them again.
  • Forgetting overhead clearance — some boxes and bins are taller than they look stacked.