We may earn revenue from the products available on this page and participate in affiliate programs. Learn More ›
In just the past 5 years, more than 250 million square feet of self-storage space has been built in the U.S. Suffice it to say that more and more people are turning to self-storage to hold their belongings. And while storage units might be a great solution for reducing clutter in the home, they require a good lock to ensure those belongings stay secure. Though many storage unit facilities require tenants to use a cylinder lock that the company provides, some leave it up to their tenants to provide their own lock. If you have your own backyard unit, you also want a secure lock handy. Finding the right padlock for the job is not an easy task. Today’s padlocks come in the standard box shape and disc shapes with exposed shackles and more secure shrouded designs. And some use combinations while others come with keys.
All of these options can make determining which ones provide the right level of security for your storage unit a challenge. Ahead, learn more about the key features of the best lock for storage unit use.
- BEST OVERALL: ABUS 20/70 Diskus Stainless Steel Padlock
- BEST BANG FOR THE BUCK: Master Lock 40DPF Stainless Steel Discus Padlock
- UPGRADE PICK: ABUS 37/80 Granit Alloy Steel Padlock
- BEST COMBINATION LOCK: Brinks Stainless Steel Resettable Combination Padlock
- BEST PADLOCK: Master Lock ProSeries Combination Lock
- BEST DISC LOCK: Master Lock Magnum M40XD Discus Padlock
- BEST OUTDOOR: Master Lock Heavy Duty Outdoor Padlock
- BEST EASY-TO-USE: Kwikset 50 MM SmartKey Padlock
Types of Locks for Storage Units
Before shopping for a storage unit lock, it’s important to understand what type of locks they use. Ahead, learn about the three different types of storage unit locks.
Cylinder Locks
Cylinder locks fit inside an existing lock mechanism on a storage unit. When a tenant rents a storage unit, the owner simply replaces the lock cylinder with a new one. Cylinder locks are more secure than padlocks or disc locks because the lock mechanism is housed inside the storage unit.
Since the cylinder lock for storage unit doors must be compatible with the lock mechanism, storage facilities that use this type of lock require their tenants to buy one directly from them when they rent the unit.
Padlocks
A padlock consists of a small square-shaped lock body with a U-shaped shackle that’s between 5/16 of an inch and 3/8 of an inch in diameter. The padlock opens with either a key or a four-pin combination. Some combination padlocks allow the user to set the combination lock for storage unit security to a custom pin number, making it easier to remember. There are also key locks that allow the owner to match the padlock key to a house key for convenience.
Disc Locks
Disc locks, sometimes called round locks, are similar to padlocks, only they have a disc shape with a curved shackle instead of a square shape with a U-shaped shackle. Since most of the shackle is covered by the lock body, a disc lock for storage unit security is more difficult to pry apart or cut with bolt cutters than a padlock. As with padlocks, round locks for storage units come in both keyed and combination varieties.
What to Consider When Choosing the Best Lock for Storage Units
Construction, size, and design all determine just how well a storage lock can prevent a thief from gaining access to a storage unit. Ahead, learn more about these and other important features of storage unit locks.
Size and Material
All locks have a shackle that fits the latch or hasp of the storage unit door. The shackle should fit the hasp as tightly as possible, thereby allowing little to no space for a would-be thief to fit a pry bar between the hasp and shackle. A ⅜-inch diameter shackle with a ⅞-inch opening is the best fit for most storage unit hasps.
In addition to the shackle size, it’s important to pay attention to the lock body. A quality lock will be made from hardened stainless steel, which is strong and resists corrosion. The most secure locks use boron carbide shackles, which resist cutting better than hardened steel.
The locking mechanism for key locks uses a series of four pins to hold the shackle inside the body. When the key is inserted, it moves these pins out of the way, allowing the lock to open. Some higher-end padlocks use five pins, adding an extra layer of security.
Security Level
When considering a lock for a storage unit, it’s crucial to consider what level of security one needs based on the unit’s location. A basic padlock is sufficient for storage units located in low-crime areas or inside a larger structure that has a secure entrance monitored by cameras. Storage units located in areas with higher crime or that have doors that are accessible from the outside are more susceptible to thieves and therefore require a padlock or disc lock that can provide a higher level of security.
Shrouded or Exposed Shackle
Padlocks and disc locks come in both shrouded and exposed shackle varieties. A shrouded padlock has a body that extends farther around the shackle than a standard padlock. This extended covering makes it more difficult for a thief to access the shackle with either a pry bar or bolt cutters, so a shrouded shackle is more secure than a lock with an exposed shackle. Padlocks with shrouded designs are typically more expensive than standard padlocks with exposed shackles.
Smart Features
Some padlocks support smart-key technology, which is useful for those who have a difficult time keeping up with a separate padlock key or who want to reduce the load on their keychain. A smart key allows the lock owner to change the pins in the padlock’s cylinder to match the key to their home, reducing the odds of being locked out of the storage unit. While this feature is handy, the owner must have the same lock brand on both their home and padlock to use this feature.
Our Top Picks
The list below includes padlocks and disc locks made by some of the best-known names in locks. It includes both high-end locks that offer maximum security for storage units located in high-crime areas as well as more affordable locks for lower-risk locations.
Best Overall
ABUS 20/70 Diskus Stainless Steel Padlock
ABUS has a reputation for making some of the toughest padlocks to defeat, and its 20/70 Diskus padlock is no exception. It may be one of ABUS’s more affordable models, but it has the formidable construction found on the brand’s high-end locks, including hardened stainless steel construction. It also has features shoppers won’t find on most disc locks, such as an anti-drill plate.
With a disc cylinder design that creates a tight fit around the hasp, the ⅜-inch shackle is well protected against pry bars. An extended shroud covers the bulk of the hasp, so it is very difficult to access the lock with a bolt cutter. The lock scores a 9 on ABUS’s 20-point security scale, which is a rating suitable for storage units located in areas with a medium risk of theft and break-ins.
Product Specs
- Type: Disc
- Bolt size: ⅜-inch diameter
- Lock dimensions: 2¾-inch diameter
Pros
- Disc design resists prying
- Hardened steel bolt and stainless steel body
- Thick ⅜-inch bolt
Cons
- More expensive than some disc locks
Get the ABUS 20/70 padlock on Amazon and Walmart.
Best Bang For the Buck
Master Lock 40DPF Stainless Steel Discus Padlock
This disc padlock from Master Lock offers a formidable level of security at a very low price. The discus padlock consists of a ⅜-inch hardened steel shackle surrounded by a stainless steel body that’s suitable for both indoor and outdoor use. The lock’s ⅞-inch-diameter opening between the shackle and the lock body is large enough to fit most hasps without leaving extra space for prybar attacks.
The keyed lock, which comes with two keys, uses a locking-lever mechanism that resists lockpicking. The disc-shaped design keeps the bulk of the shackle protected by the lock body, so it is very difficult to defeat this lock with bolt cutters.
Product Specs
- Type: Disc
- Bolt size: ⅜-inch diameter (⅞-inch opening)
- Lock dimensions: 2¾ inches by 2¾ inches
Pros
- Large ⅜-inch bolt
- Shrouded style resists prying and bolt cutters
- Affordably priced
Cons
- The locking cylinder uses only 4 pins
Get the Master Lock 40DPF padlock on Amazon and Tractor Supply Co.
Upgrade Pick
ABUS 37/80 Granit Alloy Steel Padlock
Those looking for a higher level of security who are willing to spend considerably more on a lock should consider the ABUS 37/80 Granit. This padlock increases security with a thicker shackle that measures ½-inch in diameter, an increase over the standard ⅜-inch-diameter shackle found on most locks.
An extended lock body provides added protection by making it more difficult to attack the bolt with bolt cutters. A small ⅞-inch-diameter hole helps prevent pry bar attacks. These features give the Granit a score of 10 on the ABUS scale, a ranking high enough for use in areas where there is a high risk of theft. And with its anti-corrosion coating, the Granit padlock is suitable for outdoor use.
Product Specs
- Type: Padlock
- Bolt size: ½-inch diameter (⅞-inch opening)
- Lock dimensions: 3 inches by 3 inches
Pros
- Thicker ½-inch-diameter bolt
- Anti-corrosion coating for outdoor use
- Extended shroud resists prying and bolt cutting
Cons
- Expensive
Get the ABUS 37/80 padlock on Amazon.
Best Combination Lock
Brinks Stainless Steel Resettable Combination Padlock
For those who don’t like trying to keep up with keys for a padlock, this model from Brinks offers the same high-level security as a disc lock with a four-digit combination. Unlike other combination style locks, this model allows the user to customize the combination, reducing the odds of forgetting the combination later.
The disc shape features an extended shroud that prevents prying while making it difficult to attack the bolt with cutters. Its ⅜-inch hardened steel shackle is the same size as those found on keyed disc locks. With a stainless steel body that resists corrosion, this lock is a suitable choice for outdoor use.
Product Specs
- Type: Disc lock
- Bolt size: ⅜-inch diameter (⅞-inch opening)
- Lock dimensions: 3 inches by 3 inches
Pros
- Disc lock style adds security
- User can set their own combination
- Weatherproof stainless steel construction
Cons
- Must precisely align the digits to open
Get the Brinks combination padlock on Amazon and Walmart.
Best Padlock
Master Lock ProSeries Combination Lock
The most noticeable feature of this padlock from Master Lock is the oversize brass body that extends up the side of the shackle. This extended shroud enhances the lock’s security on two fronts. It makes it much more difficult to access the shackle with bolt cutters, and it tightens the gap between the shackle and the hasp, so it’s nearly impossible to fit a pry bar between the two.
Even if a thief does manage to gain access to the shackle with a set of cutters, its boron carbide construction is more difficult to cut through than the hardened steel most padlocks use for their shackles. A resettable combination that allows the user to set a four-digit pin they’ll actually remember is a nice additional feature. The lock also comes equipped with a dust cover that prevents water and dirt from getting inside the mechanism and causing corrosion.
Product Specs
- Type: Padlock
- Bolt size: ⅜-inch diameter (1-1/16-inch opening)
- Lock dimensions: 4 inches by 4 inches
Pros
- Oversize shroud prevents cutting and prying attacks
- Strong boron carbide shackle
- Resettable combination
Cons
- Larger opening may allow more access to shackle
Get the Master Lock ProSeries lock at Ace Hardware and Lowe’s.
Best Disc Lock
Master Lock Magnum M40XD Discus Padlock
The Magnum offers a higher level of protection than most disc lock padlocks, thanks to a shackle made of boron carbide, which is harder, and therefore more difficult to cut through, than hardened steel. The tougher shackle coupled with its shrouded design makes the Magnum very effective at resisting bolt-cutter attacks. The opening between the shackle and lock body is just ⅞ inch, allowing for a snug fit on most hasps for difficult access with a pry bar.
The lock’s plastic cover has a slide that allows the owner to cover the keyhole, protecting it from the elements while preventing the lock from scratching the surface of the storage unit.
Product Specs
- Type: Disc lock
- Bolt size: ⅜-inch diameter (⅞-inch opening)
- Lock dimensions: 3 inches by 3 inches
Pros
- Boron carbide shackle resists bolt cutters
- Shrouded design prevents pry bar attacks
- Cover for keyhole
Cons
- Must ensure keyhole is covered to prevent corrosion
Get the Master Lock Magnum padlock at The Home Depot and Lowe’s.
Best Outdoor
Master Lock Heavy Duty Outdoor Padlock
With its laminated steel construction, this padlock’s weatherproof body is suitable for locks that must endure the elements. It comes with a FlexFit cover that covers the gaps between the shackle and lock body, preventing moisture from getting in and causing corrosion inside the lock. Though the shackle is thinner than others with its 5/16-inch diameter, the boron carbide material better resists cutting than standard hardened steel.
This keyed lock also includes five pins as opposed to the four found on most padlocks, so it is more difficult to defeat by lock picking. The opening on this lock is larger than a standard padlock at 1⅛ inch by ⅞ inch, which is a size suitable for larger hasps.
Product Specs
- Type: Padlock
- Bolt size: 5/16-inch diameter (1⅛-inch by ⅞-inch opening)
- Lock dimensions: 3.6 inches by 2.2 inches
Pros
- Weatherproof cover protects internal lock parts from moisture
- Boron alloy shackle
- 5-pin lock
Cons
- Smaller diameter shackle than most padlocks
Get the Master Lock heavy-duty padlock on Amazon.
Best Easy-to-Use
Kwikset 50 MM SmartKey Padlock
One of the challenges of owning a keyed padlock is keeping up with the darn keys. Kwikset solves this problem by allowing users to custom-key the padlock to match any Kwikset house key. Not only does this reduce the chances of losing the padlock key, but it also lightens the load on one’s keychain.
In addition to helping owners keep track of their storage unit key, this model prevents the problem of owners locking themselves out of a unit by requiring the key to be inside to close the lock. The Kwikset SmartKey consists of a molybdenum shackle that resists cutting and has a 1⅛-inch opening, which is suitable for larger hasps.
Product Specs
- Type: Padlock
- Bolt size: ⅜-inch diameter (2-inch by ⅞-inch opening)
- Lock dimensions: 2.6 inches by 1.5 inches by 3.2 inches
Pros
- SmartKey feature can match the key to other Kwikset keys
- Hardened steel shackle resists cutting
- Anti-lockout feature requires inserting the key to lock
Cons
- Longer shackle more susceptible to prybar attacks
Get the Kwikset SmartKey padlock on Amazon or Ace Hardware.
Our Verdict
With security features that include a hardened steel shackle, an anti-drill plate, and a shrouded body, the ABUS 20/70 padlock is an ideal choice for any storage unit. Those looking for greater security should consider the ABUS 37/80 padlock, with its beefier ½-inch shackle and hardened alloy-steel construction.
How We Chose the Best Locks for Storage Units
In selecting locks for our list, we considered both material and how the lock fit with the hasps used on storage units. A lock should be able to withstand both prying and cutting, so we only chose locks made with hardened steel. When possible, we chose models with boron carbide shackles, which are more difficult to cut than hardened steel.
Most of our selections have disc locks, which feature shrouded designs and small lock openings that make it very difficult to access the lock shackle with either bolt cutters or a prying device. Since some storage units are exposed to the elements, we also included models with designs that keep water out of the lock’s internal mechanism, preventing corrosion.
FAQs
It’s crucial to first consider what type of locking mechanism your storage unit uses before purchasing a lock. We have answers to common questions about placing locks on storage units.
Q. Do I need my own lock for a storage unit?
You typically need your own lock for a storage unit. Before purchasing a lock, check with the storage unit facility to see whether the units use a cylinder lock that you must purchase from the facility or if they require you to supply your own padlock.
Q. How do I secure my storage unit?
If your storage unit requires you to use a padlock (versus a cylinder lock), check the size of the hasp on the unit’s locking mechanism. Purchase a padlock with a shackle diameter and opening that’s just small enough to fit that hasp. The smaller the gap between the hasp and the lock shackle, the harder it is for a thief to access the lock with a bolt cutter or a pry bar.
Q. What kind of lock do you put on a storage unit?
That depends on the type of locking mechanism on the storage unit. If the storage unit uses a cylinder lock, you’ll likely have to purchase the cylinder through the storage facility. If the lock uses a hasp, you’ll need to purchase either a standard padlock or a disc padlock with a shackle size that fits the hasp.
Q. What is the best lock for an outdoor storage unit?
The best lock for an outdoor storage unit is the Master Lock 911DPF padlock. A plastic piece that covers the keyhole and a laminated body prevents water from getting inside the lock and potentially corroding the lock’s parts.
Q. What does a yellow lock on a storage unit mean?
A yellow lock typically means a storage unit is available for rental. Rental unit companies will place a red lock on a storage unit with delinquent rental fees, preventing the tenant from accessing their belongings until they pay their overdue rent.