Storage Unit Sizes Explained: 5ft, 10ft, 20ft and 40ft Self Storage Units Compared

Working out what size storage unit you need is the biggest source of confusion before you book. Get it wrong and you pay for space you never fill, or run out of room and end up booking a second unit halfway through.

Aveley Self Storage offers four container sizes: 5ft, 10ft, 20ft and 40ft. This guide translates each into real household items rather than vague square footage, then builds a situation by situation matrix to match your move, stock or spare furniture to the right size first time.

Key takeaways

• A 10ft unit (roughly 75 sq ft) comfortably holds a one bedroom flat: bed, sofa, wardrobe and around 25 to 30 boxes.
• A 20ft unit (roughly 150 sq ft) is the standard choice for a two or three bedroom house move.
• A 40ft unit (roughly 300 sq ft) holds a full four bedroom house, including white goods and garden equipment.
• The average UK household has 2.35 people, according to the Office for National Statistics, which is why most one and two person households fit comfortably into a 10ft unit.
• Ordering too small is the costliest mistake: it usually means a second unit on top of the first, not a straightforward upgrade.

What Storage Unit Sizes Does Aveley Self Storage Offer?

Aveley Self Storage offers four sizes: 5ft, 10ft, 20ft and 40ft. Each is a steel container on site at Bretts Farm, Romford Road, South Ockendon, with drive up access, so you pull a car, van or trailer to the door rather than carrying boxes down an indoor corridor.

Four sizes is fewer than some national chains list, which run to six or seven bands within a few square feet of each other. It is easier to choose between four clearly different sizes than seven that barely differ.

This guide works through each size, then builds a matrix mapping real situations, a studio flat, a three bed house, a single sofa, business pallets, a car, renovation materials, moving boxes and document archives, to the size that fits.

How Big Is Each Storage Unit Size? Dimensions and Floor Area Explained

Based on Aveley Self Storage’s published dimensions, the four sizes break down as follows. The 5ft figures are estimated from the same width and height as the 10ft unit and should be confirmed on a quote, since an exact published spec for it was not available at the time of writing.

A standard UK single garage measures around 2.55m by 5.2m, about 143 sq ft, according to garage specialist Chart Garages. A 10ft unit at 75 sq ft is a little over half that. A recommended double garage interior runs to around 5.5m by 5m, close to 300 sq ft, matching the 40ft unit almost exactly.

A standard UK car parking bay is 2.4m by 4.8m, about 124 sq ft, per the Institution of Structural Engineers, cited by the RAC. Picture the 20ft unit as that bay with a bit of extra width down each side.

What Fits in a 5ft Storage Unit?

A 5ft unit is Aveley Self Storage’s smallest size, at roughly 35 to 40 sq ft. Think large walk in wardrobe or generous boxroom.

In real items, a 5ft unit typically holds one of these:

• A single or small double bed frame and mattress, a chest of drawers, and 10 to 15 boxes.
• A three seater sofa or a couple of armchairs plus several boxes stacked around it.
• 20 to 30 standard moving boxes stacked to shoulder height, with a narrow aisle to the back.

At roughly 295 cu ft, a 5ft unit holds a bit less than half a Transit van’s load area (a medium wheelbase, standard roof Transit carries around 400 cu ft, based on Ford’s published L3H2 load volume). If your items fill a Transit van and then some, the 5ft is already too tight and you should look at a 10ft.

What Fits in a 10ft Storage Unit?

A 10ft unit is Aveley Self Storage’s most booked size, and at 75 sq ft it is the natural fit for a one bedroom flat, a house share clear out, or a fuller business stock delivery.

In real terms, a 10ft unit typically holds:

• The full contents of a one bedroom flat: double bed, wardrobe, sofa, dining table and two chairs, a washing machine, and around 25 to 30 boxes.
• A three piece suite plus a dining set and white goods, if you are storing furniture rather than a whole flat.
• Roughly 40 to 50 standard moving boxes, stacked with a small aisle kept clear.

At roughly 580 cu ft, a 10ft unit holds about one and a half Transit van loads, matching how most one bedroom flat moves actually run. If torn between the 5ft and the 10ft, remember most people underestimate how many boxes a kitchen alone produces. Unless you have already decluttered hard, go with the 10ft.

What Fits in a 20ft Storage Unit?

A 20ft unit, at around 150 sq ft, is the size most two and three bedroom house moves land on. It is double the floor area of the 10ft, at the same 7ft 9in height.

What a 20ft unit typically holds:

• The full contents of a two bedroom house: two bedrooms of furniture, a living room suite, dining furniture, white goods, and 50 or more boxes.
• A three bedroom house already partly decluttered, or one storing a room or two short term during a renovation.
• A small car or a motorbike plus a reasonable amount of other household storage around it.

At roughly 1,160 cu ft, a 20ft unit is close to two Luton van loads (a Luton’s load area holds around 530 to 710 cu ft, generally quoted as enough for a two to three bedroom house in one run). If a Luton struggles to take everything from a three bedroom house in one trip, common once the loft and shed are included, a 20ft is built to absorb the overflow.

What Fits in a 40ft Storage Unit?

A 40ft unit is Aveley Self Storage’s largest size, at around 300 sq ft and 8ft 6in high, the extra height adding useful stacking room for tall or bulky items.

In real terms, a 40ft unit typically holds:

• The complete contents of a four bedroom house: every room of furniture, all white goods, garden furniture and equipment, and well over 100 boxes.
• A house move combined with a business’s worth of stock or tools, consolidating two smaller moves into one unit.
• A car and a substantial amount of household or business storage alongside it, with room to walk round the vehicle.

At roughly 2,550 cu ft, a 40ft unit holds around six Transit loads or four to five Luton loads. Few single house moves need all of that at once. The 40ft suits combined situations, a house move plus a garage clearance, or a landlord consolidating two flats between tenancies, rather than one average household.

Storage Unit Size Guide: Which Size Fits Your Situation?

Match your situation on the left to the recommended size, with the reasoning rather than just the answer.

What Size Storage Unit for a Studio or One Bedroom Flat Move?

A studio or one bedroom flat move is the classic case where people underestimate what they own. On paper it sounds like “not much.” In practice it is a bed, a sofa, a wardrobe and every drawer’s worth of items.

A 10ft unit suits most one bedroom flat moves: a double bed, wardrobe, sofa, small dining set, a washing machine, and around 25 to 30 boxes, the typical yield once the kitchen, bathroom and wardrobe are all packed.

A couple in a one bedroom flat in South Ockendon relocating for a few months while renovating would typically fill a 10ft to about three quarters capacity, leaving room to reach the back without unpacking. If most furniture has already gone and only boxes remain, a 5ft may be enough, but check the matrix above first.

For household moves specifically, see the moving home storage page for how Aveley Self Storage supports people relocating around Thurrock.

What Size Storage Unit for a Two or Three Bedroom House Move?

A two or three bedroom house move is where the 20ft unit earns its size. Two or three bedrooms of furniture, a full living room, a dining suite, white goods, garden equipment and often 50 or more boxes once the loft and shed are cleared needs the extra floor area a 10ft simply does not have.

A family of four moving from a three bedroom semi in Aveley into a rental while waiting to complete on a new build would typically need a 20ft, sometimes stretching to a 40ft if garden furniture, tools and a loft clearance are all being stored rather than sold or skipped.

A useful rule of thumb: count the bedrooms, then add one size band per extra bedroom beyond the first. One bedroom is a 10ft. Two to three bedrooms is a 20ft. A full four bedroom household, or two households combined, moves into 40ft territory.

For furniture specifically, rather than a whole house, see the furniture storage page.

What Size Storage Unit for Business Stock, Pallets and Equipment?

Business storage sizing is driven by pallets rather than rooms. A standard UK pallet footprint is around 1.2m by 1m, roughly 13 sq ft, before any stacking.

A 10ft unit takes 5 to 6 pallets at floor level with an aisle to access them, or more stacked safely to shoulder height. A 20ft takes 10 or more pallets, suiting a small ecommerce operation holding a season’s stock, or a tradesperson storing materials and tools.

A sole trader running an online shop from home, with stock spiking around Christmas, typically starts in a 10ft and moves to a 20ft once order volume grows past a few hundred units a month. Document heavy businesses, accountants, solicitors, or anyone keeping years of paper records, need far less floor space and are often better suited to a 5ft or 10ft archive setup.

See the warehouse storage page for stock heavy business storage, and the document archive storage page for paper records.

What Size Storage Unit for a Car or Motorbike?

Storing a car needs more length and access room than most people assume. A small hatchback is around 4.2m long and a family car closer to 4.6m, so once you add room to open doors and walk round the vehicle, a 20ft container is the realistic minimum, matching the parking bay footprint described earlier.

A motorbike is different. Even a large touring bike is under 2.5m long and under a metre wide, so a 10ft unit comfortably takes a motorbike plus a reasonable amount of other storage, tools, a cover, spare parts, without needing the larger size.

Before storing any vehicle, drain excess fuel where practical and check current terms for what is permitted. See the vehicle storage page for storing a car, motorbike or trailer at Aveley Self Storage.

What Size Storage Unit for Renovation and Building Materials?

Renovation storage is easy to underestimate because people picture the materials rather than the furniture displaced at the same time. A kitchen refit alone, cabinets, worktops, appliances and the existing furniture pulled from the room, can fill a 10ft before a single tile or bag of plaster is added.

For a single room renovation, a 10ft is usually enough: displaced furniture, boxed belongings, and a modest stock of flooring and paint. For a whole house renovation, where several rooms are stripped out at once, a 20ft is the safer choice, and larger projects sometimes justify a 40ft, particularly where plasterboard sheets, timber lengths and a full kitchen’s worth of units need storing flat rather than stacked on end.

One practical point: plasterboard and timber need to be stored flat or upright and supported, not leant loosely against a wall, or they warp. That uses more floor space than the same weight of boxed items.

Who Shouldn’t Use Each Storage Unit Size (And Who Should Look Elsewhere)

Getting the size wrong in either direction wastes money, and sometimes a container is not the right answer at all.

Skip storage altogether if you only need somewhere for a handful of boxes for a week or two, say while a single room is painted. Setting up even a 5ft unit for that short a period usually costs more in time and admin than it saves. A loft, a garage, or a favour from family covers that gap better.

The 5ft is not right if you are moving a full flat rather than storing a single item or a run of boxes. The 40ft is not right for anyone storing less than a full house’s worth of belongings. It is the largest and most expensive unit, and renting one for a single room’s furniture means paying for floor space that sits empty.

If you need to access stock several times a day with staff picking constantly, a drive up container site is workable but was not built around that workflow the way a staffed warehouse is. For occasional access or seasonal overflow, container storage suits business use well.

How Much Does Each Storage Unit Size Cost? A Real Cost Per Size Sanity Check

Storage pricing depends on size, rental length and demand at the time, so the only accurate figure is a live quote from Aveley Self Storage’s quote page. What you can do yourself is a cost per cubic foot check, the fastest way to spot whether you are paying for space you will not use.

Here is the method, using illustrative figures only, not Aveley’s actual prices, to show the working. Say a 5ft is quoted at a certain weekly rate, and a 10ft comes back at roughly one and a half times that rate. On paper the 10ft looks pricier. But it holds around double the cubic footage of the 5ft, so the true cost per cubic foot is lower on the bigger unit, not higher. That pattern holds across storage generally: the smallest sizes tend to cost more per square foot, because there is a fixed cost to renting any unit, however small.

With two real quotes in hand, divide the weekly price by the approximate cubic footage from the table earlier in this guide. Whichever size gives the lower cost per cubic foot, while still fitting everything with room to spare, is usually the better value choice, not necessarily the cheapest number on the page.

The Biggest Storage Unit Size Mistakes People Make

Ordering too small. The costliest mistake by far. Running out of room mid load means leaving items behind, cramming a unit so nothing at the back is reachable, or booking a second unit on top of the first, which usually costs more overall than booking the right size from the start.

Ordering too big out of caution. The quieter but still expensive mistake. Booking a 20ft “just in case” when a 10ft would do means paying the larger rate every week for space that never fills.

Not leaving a walkway. Filling a unit wall to wall without a route to the back means every visit involves unpacking the front to reach anything behind it. Keep roughly a fifth of the floor area clear as an aisle if you expect more than one visit.

Forgetting how irregular items behave. Bikes, mattresses on their side and garden tools do not stack as efficiently as boxes. If a lot of what you are storing is awkward rather than boxable, size up a band from what the matrix suggests.

Storage Unit Sizes vs the Alternatives: Garage, Loft, Attic and Van Storage

A container is not the only option, and it is worth being honest about when alternatives make more sense.

A garage at home. If you already have an empty one, it is free and exactly what a 10ft or 20ft unit is trying to replicate. The downside is access and security are rarely to the same standard, and a garage full of belongings usually means the car ends up back on the drive.

Loft or attic space. Genuinely useful for lightweight items, seasonal decorations, suitcases, out of season clothing, but loft floors have real weight limits and are rarely boarded across their full area, so heavy furniture and boxes of books are a poor fit.

Renting a van and doing it yourself in stages. Works for a slow, staged declutter spread over weeks, but is inefficient for anything you need to move once and store for months, since you pay for van hire repeatedly rather than once for a unit.

Indoor personal storage from a national provider. Companies such as Safestore or Big Yellow offer indoor, corridor style units, generally trolley access rather than drive up. That suits city centre customers without a car, or anyone visiting items very frequently on foot. For anyone with a car or van who wants to drive straight up to their unit, container storage like Aveley Self Storage’s is usually faster and more practical, and typically cheaper per square foot than city centre indoor storage.

Storage Unit Size Myths: What People Get Wrong

Myth: bigger is always safer, so size up “just in case.” As the cost check above shows, oversizing carries a real ongoing cost. Sizing accurately, with a small buffer rather than a large one, is nearly always better value.

Myth: square footage tells you everything. It ignores height and how irregularly shaped your items are. Two units of the same square footage can hold very different amounts depending on ceiling height and how boxable the contents are.

Myth: a unit needs to hold everything from every room at once. Many people storing during a move or renovation only need to store what will not fit in the new space temporarily, not every possession. Working out what is actually being stored often drops the required size by a full band.

Myth: you have to commit to one size for the whole rental. If you start in a 10ft and outgrow it, moving up a size is normally straightforward with reasonable notice, so it is not a one time, irreversible decision.

What Size Storage Unit Should You Choose? Our Verdict

Moving a one bedroom flat: choose the 10ft. It is built around exactly that job, and the 5ft is too easy to outgrow once the kitchen and wardrobe are packed.

Moving a two or three bedroom house: choose the 20ft as your default, and only step up to the 40ft if you are combining the move with a business’s worth of stock, a full garage clearance, or a vehicle stored alongside it.

Storing a single large item, a run of document boxes, or the contents of a decluttered spare room: the 5ft is almost always enough, and there is little reason to pay for more.

The single best piece of advice here: use the size guide alongside a real conversation with the team before you book. The matrix above gets you close, but a two minute call on 01708 922540, or a message to sales@aveleyselfstorage.co.uk, catches the edge cases a table cannot. Get a firm figure from the quote page before committing.

Storage Unit Sizes FAQ