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Storage Unit Size Guide
How Big Is a 15x20 Storage Unit? Dimensions, What Fits, and Who It's For
Three hundred square feet in a genuinely wide shape. Two vehicles side by side, a large household, or a working contractor bay, with the arithmetic behind each.
Compare Every Size
- 5x525 sq ft
- 5x1050 sq ft
- 5x1575 sq ft
- 10x10100 sq ft
- 10x15150 sq ft
- 10x20200 sq ft
- 15x20300 sq ft
- 10x30300 sq ft
- 20x20400 sq ft
- 10x40400 sq ft
- 15x30450 sq ft
- 20x25500 sq ft
- 20x40800 sq ft
Other Space Types
On This Page
- What a 15x20 Storage Unit Actually Is
- What Fits in a 15x20 Storage Unit
- What Does Not Fit in a 15x20 Storage Unit
- Who a 15x20 Storage Unit Is Right For
- How to Know If You Should Size Up or Down
- How to Pack a 15x20 Storage Unit Efficiently
- Climate-Controlled or Standard: Which 15x20 to Choose
- What a 15x20 Storage Unit Costs and How to Think About Value
- Frequently Asked Questions
- Reserve a 15x20 Storage Unit Near You
Section 01
What a 15x20 Storage Unit Actually Is
A 15x20 measures 15 feet wide by 20 feet deep: 300 square feet of floor, or a rectangle 180 inches by 240 inches. With 8-foot ceilings that gives you 2,400 cubic feet.
Here is the thing worth knowing before anything else. A 10x30 has exactly the same 300 square feet. They are not remotely the same unit.
A 10x30 is a corridor: ten feet across, with a back wall thirty feet from the door. A 15x20 is a room. Fifteen feet of width takes two vehicles side by side, or racking down both walls with a pallet jack able to turn between them. Identical square footage, and a completely different set of things you can do with it.
The Floor, Drawn to Scale
Looking straight down, here is the floor at true proportion with one layer of 18-inch medium cartons across it. Ten fit across the 180-inch width and thirteen run down the 240-inch depth, giving a hundred and thirty per layer.
240 in / 20 ft deep · door on left wall
A hundred and thirty medium boxes per layer. Five safe layers gives about 650 boxes, if the unit holds nothing else.
The Unit in Three Dimensions
Square footage undersells a unit this size, because what you are renting is volume. Both cutaways below show the same 15x20 at the same scale. The only difference between them is how the boxes are stacked.
Stacked five layers high
One layer on the floor
At this size the gap between those two drawings is enormous. Packing to head height rather than waist height is worth more square footage than most renters would ever pay for.
Same Square Footage, Different Unit
If a 10x30 and a 15x20 are both available near you at a similar price, take the 15x20 unless you specifically need thirty feet of length. Width is worth more than depth to almost every renter, because width is what lets you reach things without moving other things.
Section 02
What Fits in a 15x20 Storage Unit
Two Vehicles, Side by Side
This is the headline capability. At 180 inches of width, two vehicles at roughly 72 inches each occupy 144 inches, leaving about three feet to divide between the middle and the two sides. That is enough to open a door and walk through, which a 10-foot-wide unit never allows however long it is.
- Two sedans or compacts comfortably, at 20 feet of depth against vehicle lengths of 14 to 17 feet.
- One vehicle plus a boat or trailer under about 18 feet overall.
- One vehicle plus a full workshop down the opposite wall.
- Four to six motorcycles or ATVs with room to work on them.
Check the Door, Not Just the Floor
Interior dimensions are only half the question. The roll-up door opening is narrower and lower than the unit itself, and at this size it is what actually decides whether a tall vehicle, a van with roof equipment or a trailer will go in. Confirm the door opening at the specific facility before booking anything close to the limits, particularly on height.
Storing a vehicle also carries requirements that storing goods does not: proof of current registration and proof of insurance. Motorised vehicles must be operable and free of leaking fluids. Towable trailers, including travel trailers, fifth wheels, pop-ups and utility trailers, do not need to be operable. Our vehicle storage page has the detail.
A Five to Six Bedroom Household
As a domestic benchmark, a 15x20 takes a large family home complete: several bedroom sets, multiple living areas, a dining room, all major appliances, the garage contents, patio furniture and 200 to 250 cartons, with an aisle left to reach any of it. For most households this is more than they will ever need.
Shelving and Racking
A 15x20 has 70 linear feet of wall. Shelving along both 20-foot walls and the 15-foot back gives 55 linear feet of run, and at five shelves high that is about 275 linear feet of shelf with a full aisle and turning room. Our business storage page covers commercial use.
Section 03
What Does Not Fit in a 15x20 Storage Unit
Beyond This Size
- Anything longer than 20 feet. Extended-bed pickups, most motorhomes, larger boats and trailers over about 18 feet overall.
- Three vehicles. Two side by side is the limit at 15 feet of width, and 20 feet of depth will not take two nose to tail with access.
- Anything taller or wider than the door opening, which is lower and narrower than the unit itself.
- Palletised inventory beyond about 15 floor positions without racking.
- Two full households at once. One large one, comfortably. Two is a 20x40.
Vehicles and Prohibited Items
- Vehicles without documentation. Proof of current registration and proof of insurance are required, and motorised vehicles must be operable with no leaking fluids.
- Flammable, combustible or hazardous materials: gasoline, propane, paint, solvents, fireworks, ammunition. This catches out contractors and equipment owners more than anyone, so drain fuel before storing.
- Perishable goods, or anything that attracts pests.
- Living things, including plants and animals.
- Anything illegal or stolen.
- Occupied or operational use. A storage unit is not premises. No working from inside it, no customers, no utilities.
If You Only Need Length, You Are in the Wrong Unit
People arrive at a 15x20 wanting to store one long thing, usually a boat or an RV. If that is the whole job, a 10x40 gives you twice the length for similar square footage, and a dedicated parking space sized by length will usually cost less than either.
Rent a 15x20 when you need width: two vehicles, a workspace beside a vehicle, or racking you can turn between. See our RV storage and boat storage pages for the alternatives.
Our full storage FAQs cover prohibited items in detail, and your rental agreement is the controlling document. At this size, where a unit may hold an entire inventory or a vehicle, read the agreement rather than relying on a general guide, including this one.
Section 04
Who a 15x20 Storage Unit Is Right For
Households Storing a Large Home
Five or six bedrooms including the garage, the patio and the loft, in one unit with an aisle. Above a 10x30 this is the first size that stops requiring compromise.
Two-Vehicle Households
A classic car and a daily driver, two seasonal vehicles, or a vehicle plus a boat. Indoor storage protects paint and interiors in a way outdoor parking cannot, and 15 feet of width means you can actually get into both.
Contractors and Trades
A work vehicle down one side, racking and materials down the other, and room to load in between. With 24/7 gate access and month-to-month terms, this works as a yard and a stockroom without a commercial lease.
Businesses Outgrowing a Garage
Twelve to fifteen pallet positions, 275 linear feet of shelf and a floor plan you can lay out properly. For an e-commerce operation or a distributor this is frequently the step taken instead of a first warehouse.
Estate Clearances of Large Properties
When a large family home has to be emptied at once so it can be listed, a 15x20 takes the contents in a single move. Our storage scenarios pages cover these situations.
Section 05
How to Know If You Should Size Up or Down
Shape First, Then Size
At 300 square feet the question is not how much space you need but what shape it should be. A 15x20 and a 10x30 are the same area. Choose by what you are storing, not by the number.
A 15x20 Is Right If Any of These Are True
- Two vehicles are going in side by side
- You need to work beside what you store
- You want racking on both long walls with a path between
- You are storing a five to six bedroom household
- Nothing you own is longer than about 18 feet
Choose Something Else If Any of These Are True
- You are storing one long item and nothing else, which wants a 10x40 or a parking space
- You need three or more vehicles, which wants a 20x40
- You want doors fully open on both vehicles, which wants a 20x20
- A 10x30 is meaningfully cheaper and you will not open the unit
- Your household is four bedrooms or fewer, which fits a 10x20 or 10x30 for less
Before You Rent This Much Space
At 300 square feet the monthly cost is high enough that what goes in deserves a decision rather than a default. If a meaningful share would be furniture or equipment you already know you will not use again, storing it for a year will usually cost more than replacing it.
Sort before you load. It routinely moves people down a size, and occasionally out of storage altogether.
Our storage size calculator builds a recommendation from an item-by-item inventory, and the size guide shows every size side by side.
Section 06
How to Pack a 15x20 Storage Unit Efficiently
Three hundred square feet is enough space to waste badly, and the units that end up half usable are the ones loaded straight off the truck in whatever order it came.
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Plan the Layout Before Anything Arrives
At this size an unplanned load wastes more space than most people rent in total. Decide where vehicles, racking, heavy equipment and boxes go before the first item comes off the truck, and tell whoever is helping.
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Racking Beats Stacking, Decisively
Freestanding shelving or pallet racking along the walls turns floor area into usable volume and keeps everything individually reachable. Above about 300 square feet this is the single highest-return decision you will make.
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Keep a Full-Length Aisle, and a Turning Space
Run a clear path from the door to the back wall, and leave enough room near the door to turn with a hand truck or pallet jack. Losing roughly a third of the floor to access is the correct trade on a unit you will visit.
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Heaviest and Least Needed at the Back
Equipment, appliances and archive stock go furthest from the door. They are also the sturdiest platforms to stack against.
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Build Upward to About 80 Inches
Uniform cartons reach roughly 80 percent volume efficiency against 55 percent for mismatched sizes. On a unit this large that difference is measured in hundreds of cubic feet.
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Prepare Vehicles and Fuel-Powered Equipment First
Drain mowers, generators and power equipment, since fuel is not permitted inside. For a stored vehicle, clean it, inflate the tyres, and disconnect or tend the battery.
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Decide the Vehicle Bays Before Anything Else
If vehicles are going in, they claim two lanes of width and most of the depth. Mark out where they sit before the first pallet lands, because a car cannot be added to a full unit afterwards.
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Photograph Each Zone and Keep the Map
On a rental this size, running for a year or more, a few phone photos taken the day you load will save hours later. Label cartons on the face that points at the aisle.
Our full storage tips guide goes further on protecting furniture and preparing equipment for storage.
Section 07
Climate-Controlled or Standard: Which 15x20 to Choose
We offer 15x20 space in both standard and climate-controlled configurations, though availability varies by location and climate control is less common at this size.
Standard Unit
Enclosed and secure, keeping weather and direct sun off everything inside. Interior temperature tracks the outside temperature, which across much of our footprint means well over 100 degrees in summer and below freezing in winter.
Fine for:
- Vehicles, trailers and towable equipment
- Tools, machinery and contractor materials
- Plastic totes, metal shelving and durable goods
- Lumber, fixtures and non-perishable stock
Climate-Controlled Unit
Temperature-regulated, holding an interior range year round. That protects against the extreme heat and hard freezes that warp wood, crack vinyl, degrade adhesives and damage electronics.
Worth it for:
- Electronics, screens and anything with a battery
- Wood furniture, cabinetry and millwork
- Business records, artwork and instruments
- Products with a temperature-sensitive shelf life
An Honest Limitation Worth Knowing About
Climate control at our facilities means temperature regulation. It does not mean moisture management, and we do not want anyone assuming otherwise on the strength of the name.
Temperature and moisture are two different threats. If you are storing something genuinely moisture-sensitive, such as documents, leather, upholstery, electronics or finished millwork, a temperature-regulated unit addresses one of those and not the other. Handle the second yourself: seal items in airtight containers rather than cardboard, add desiccant inside them, and keep everything off the concrete on pallets or risers. Those steps cost very little and do more for moisture-sensitive goods than any unit type will.
At this size, where a single tenant may be storing an entire inventory, that distinction is worth acting on rather than noting.
More detail is on the climate-controlled storage page.
Section 08
What a 15x20 Storage Unit Costs and How to Think About Value
What a 15x20 costs depends on your market, the specific facility, whether the unit is climate-controlled and what is available when you book. Rather than publish a range that goes stale, we point you at live pricing for the locations near you.
The Cost Logic That Does Not Change
- Larger units cost less per square foot, but the curve flattens at the top of the range. The saving from stepping up is real between small units and much smaller between large ones.
- Availability is the real constraint at this size. There are far fewer of these than there are 10x10s, and they do not come free often. If one is available where you need it, that matters more than a small price difference.
- Compare against commercial rent, not against other units. For a business, the useful comparison is the price per square foot of warehouse or flex space in your market, plus its lease term, deposit and build-out. This is usually not close.
- Two units can beat one. Check a 15x20 against two 10x20 units at the locations near you. One is simpler; two are sometimes cheaper and let you separate what you need from what you do not.
What Is Included, and One Thing We Cannot Do
Every rental includes a free lock, month-to-month terms with no long-term contract, and 24/7 gate access at nearly all locations. A protection plan is required at checkout at all of our facilities. Check first whether your existing business or homeowner policy already extends to goods stored off premises, and read your rental agreement for what the plan does and does not cover.
Our facilities are fully automated and unstaffed. You rent online, your gate code arrives by email and text, and you go straight to the unit. Because nobody is on site, we cannot accept deliveries on your behalf. That matters more at this size than any other, because businesses renting 15x20 space often assume inventory can be shipped straight to the unit. It cannot. If your operation depends on that, this is not the right fit, and it is better to know now. More on how our facilities work is on the why choose 10 Federal Storage page.
How Big Is a 15x20 Storage Unit?, Frequently Asked Questions
A 15x20 is 15 feet wide by 20 feet deep, for 300 square feet of floor. With 8-foot ceilings that comes to 2,400 cubic feet, comparable to a wide two-car garage bay.
About 650 medium cartons wall to wall, five layers high, with nothing else inside. Leave a full-length aisle and the figure is 450 to 460. Alongside a large household's furniture, plan on 200 to 250.
Yes, side by side. At 180 inches of width two vehicles at roughly 72 inches each leave about three feet to divide between the middle and the sides, which is enough to open a door and walk through. Confirm the roll-up door opening before booking.
They are the same 300 square feet and nothing else about them is the same. A 10x30 is ten feet wide with a back wall thirty feet away. A 15x20 is wide enough for two vehicles or for racking on both walls with a path between. Take the 15x20 unless you specifically need the length.
A five to six bedroom home complete, including appliances, garage contents and patio furniture, with 200 to 250 cartons and an aisle left over.
Twelve to fifteen standard pallets on the floor with room to move between them, and considerably more if racked. A standard pallet is 48 by 40 inches.
Almost never. Twenty feet of depth rules out most motorhomes, and height is usually the harder constraint since the door opening is lower than the ceiling. For RVs, a dedicated space sized by length is the better product.
Figures on this page assume 8 feet, consistent with the rest of the range. Confirm the specific unit before booking if you are stacking or storing anything tall, since clear heights can vary in large-format buildings.
Shelving along both 20-foot walls and the 15-foot back gives 55 linear feet of run, and at five shelves high that is about 275 linear feet of shelf, with a full aisle and turning room left.
It depends what is going in. Choose temperature regulation for electronics, wood, documents, artwork and temperature-sensitive stock. A standard unit is fine for vehicles, tools, materials and durable goods. Our climate-controlled units regulate temperature only, so seal moisture-sensitive goods either way.
Reserve a 15x20 Storage Unit Near You
The 15x20 is the first size where width stops being the constraint. It takes two vehicles side by side, a five to six bedroom household, or a contractor operation with racking down both walls and room to turn a pallet jack. If you have the same 300 square feet available as a 10x30, take this shape instead unless you specifically need the length.
See available 15x20 units and pricing Compare all unit sizes
