Top 5 Best Padlocks for Storage Units | Ultimate 2024 Reviews

Last updated Feb 15, 2024

Disclosure: As an Amazon Associate I earn from qualifying purchases.

Investing in a secure padlock is important to prevent the anxiety that accompanies storing your belongings in a public storage unit. Having years of experience storing valuable items in self-storage units, we’re happy to help you choose the best padlocks for storage units.

In this guide, we provide you with our top five picks, ranging from extremely high-security to basic security that gets the job done. The first step is to calculate how much the belongings you plan to store are worth to get a ballpark figure. In most cases, if you plan to store electronics, expensive furniture, musical instruments, or anything that’s worth at least a few hundred bucks, it’s wise to choose one of the first three locks in our guide.

The upfront investment is worth it to set your mind at ease and skip over the dinky overpriced locks sold at most storage facilities. Let’s get started below with a chart that lists the most important specs of each lock. After the chart, we share helpful reviews of each lock and some tips to help keep your possessions secure for the long haul.

Lock Description
#1) ABUS Granit 37/60 Padlock

  • Material: Hardened Alloy Steel w/ Cataphoretic Coating
  • Shackle Diameter: 11 mm
  • Dimensions: 2.56” x 1.38” x 3.35” (LxWxH)
  • Weight: 1.46 lbs
  • Model: ABU3760CSC
  • Price: $$$
#2) Medeco M3 Shrouded Boron Padlock

  • Material: Boron Alloy Steel Shackle
  • Shackle Diameter: 5/16″
  • Dimensions: 2.39” x 1.33” x 3.76” (LxWxH)
  • Weight: 2 lbs
  • Model: 54T52500
  • Price: $$$$
#3) ABUS 20/70 Diskus Stainless Steel Padlock Keyed Different

  • Material: Stainless Steel Inside & Out
  • Shackle Diameter: 10 mm
  • Dimensions: 2.81” x 1.17” x 3.39” (LxWxH)
  • Weight: 12.8 oz
  • Model: 20/70 KD B
  • Price: $$
#4) Stanley Hardware S828-160 CD8820 Shrouded Hardened Steel Padlock

  • Material: Hardened Steel, Hardened Molybdenum Alloy Steel Shackle
  • Shackle Diameter: 7/16″
  • Size: 60 mm
  • Weight: 2.05 lbs
  • Model: S828-160
  • Price: $$
#5) Master Lock 40DPF Stainless Steel Discus Padlock

  • Material: Stainless Steel, Hardened Steel Shackle
  • Shackle Diameter: 3/8″
  • Size: 2.75” Diameter
  • Weight: 9.6 oz
  • Model: 40DPF
  • Price: $

Reviews of the Best Padlocks for Storage Units

Now that you’ve had the chance to check out the locks, you know that the best types of locks are shrouded and disc locks. One of the key dimensions to check before investing in a lock for your storage unit is the hasp opening size. The hasp is the part on your storage locker or unit that houses the lock. The easiest way to determine the size of the opening is to ask the owners of the storage facility or a knowledgeable employee. If you prefer to do it yourself while inspecting the unit, any flat ruler or measuring tape will work.

Once you know the size of the opening, it’s a good idea to choose a lock that fills out the opening to reduce the amount of play for the most secure fit. All of the locks in our guide have a shackle diameter of 7/16″ or smaller, which fits most public storage units. However, there are cases where a 7/16″ is too large, so be sure to check with the storage facility. Now, let’s move on to the reviews.

#1) ABUS Granit 37/60 Padlock

We’re big fans of ABUS Granit series locks here at Anti-Theft Boss, and the 37/60 is the best cylinder lock for storage units in the Granit collection. This is the type of lock you want if you plan to store your most valuable possessions and keepsakes. ABUS locks are made in Germany under strict quality guidelines. When you invest in the 37/60, it’s wise to choose the carded version of the lock to ensure the key cannot be duplicated without presenting the security card.

In addition to the card, the lock includes two keys, and one of the keys features an LED light in case you choose an outdoor unit. Additionally, this lock is an excellent choice for a storage unit exposed to the elements because of the Granit cataphoretic coating that provides a whopping 40 years or more of corrosion protection.

Other highlights of this lock are the removable shackle with a double ball locking mechanism that requires two cuts to break, the ABUS-Plus disc cylinder that’s virtually impossible for an amateur to pick, and the hardened steel shackle guard that protects the shackle against tool attacks. Overall, this is our favorite lock for people who desire a high-security storage lock to keep their most important possessions safe. For people who are storing low-value items, it’s probably more lock than you need.


  • The included security card provides unauthorized key duplication (store the card in your home safe)
  • ABUS Granit locks hold up for decades of use, in other words, you get your money’s worth
  • Even pro thieves won’t want to try and pick this lock when there are easier targets
  • An excellent choice for outdoor lockers exposed to the elements
  • Drillproof, and it’s nearly impossible to get past the shackle guard with tools
  • Includes 2 keys, 1 w/ LED light


  • The 11 mm shackle may be too big for your unit
  • When unlocked, the shackle disconnects from the body making it impossible to hang the lock from your unit
  • The key may stick a bit when trying to open/close the lock

#2) Medeco M3 Shrouded Boron Padlock

Similar to ABUS Granit, the Medeco3 padlock is for people who are serious about securing their possessions. The biggest advantage of choosing Medeco’s lock over the Granit 37/60 is the shackle size. Medeco has a shackle diameter of 5/16″ to fit almost all storage facility hasps, while the 37/60 is not quite as universal. The biggest disadvantage of choosing Medeco’s lock is the price. At the time of this writing, it is the most expensive lock in our guide, even making the 37/60 look affordable.

Having said that, this lock is the most secure in our guide. The rotating tumbler pin system makes this lock even harder to pick than an ABUS Granit lock. Plus, you get the same insurance against unauthorized key duplicates with the included security card. Medeco’s patented keys may only be duplicated by Medeco or authorized Medeco service centers.

In addition to those features, the cylinder houses hardened steel inserts to protect it against all types of physical attacks including drill attacks. In reality, when you secure your unit with this lock, you need to worry more about the quality of the hasp provided by the facility than your lock because almost no one is getting past this lock without enough time and expertise.


  • The most advanced pin system of the locks in our guide for protection against pick attacks
  • A smaller shackle size to fit through all storage facility hasps
  • Medeco’s patented and protected key system to prevent unauthorized key duplication
  • A shrouded boron alloy steel shackle for ultimate protection against cutting and pulling
  • Weather-resistant for optimal outdoor and indoor use
  • Functions smoothly with no problems turning the key


  • The highest cost of the locks in our guide
  • A lock of this caliber may draw unwanted attention, and remember, if the storage facility hasp is poor quality, thieves will attack the hasp fist

#3) ABUS 20/70 Diskus Stainless Steel Padlock Keyed Different

Now for the best disc lock for a storage unit, the ABUS 20/70. Disc locks are popularly used on storage units, which is a good thing since they blend in well with other locks. The key difference here is that an ABUS disc lock is better than a cheap Master Lock or Brinks disc lock. Unlike cheap disc locks that are easy to pick, the 20/70 lock features the same ABUS-Plus disc cylinder used in the company’s Granit locks for protection against pick attacks. Plus, the cylinder cover protects the keyhole against the elements and prevents grime from entering.

Disc-style padlocks are good for storage units because they leave almost no room for thieves to attack the shackle, without the need for a shroud similar to what’s on the first two locks. Additionally, they’re usually more affordable than high-security padlocks. The 20/70 body is made of stainless steel both inside and out to prevent corrosion, while the shackle itself is made of high-quality stainless steel.

Lastly, the keyed security is well beyond what you’ll find in a cheap disc lock. The 20/70 includes two keys and a security card to help protect against unauthorized dupes. You’ll also like that the lock retains the key while opened to avoid misplacing the key while you’re inside your unit. All in all, this is our favorite disc lock for storage units, just make sure the 10 mm shackle diameter is okay at your facility.


  • The best disc lock for storage units
  • More affordable than the first two padlocks in our guide
  • Stainless steel both inside and outside with a cylinder cover to prevent corrosion in harsh weather
  • ABUS-Plus disk cylinder for an advanced level of anti-pick protection compared to cheap disc locks
  • Blends in well with other storage locks
  • Made in Germany


  • The key must be aligned correctly to prevent breaking the key
  • Getting keys made is not convenient

#4) Stanley Hardware S828-160 CD8820 Shrouded Hardened Steel Padlock

Stanley’s shrouded padlock is an excellent budget alternative to pricier ABUS and Medeco locks. Although make no mistake, this is a diesel lock that’s larger in person than it looks in photos. Compared to 4-pin and 5-pin cylinders, this lock’s 6-pin cylinder is harder to pick and provides a level of protection closer to what ABUS offers than most cheap padlocks.

Similar to the Granit 37/60 lock, this lock features dual stainless steel bearings for anti-pry protection. You also get a keyway cover to protect against weather and drill attacks along with a hardened steel shroud & body for an added layer of protection. One thing to keep in mind is that the shackle diameter is 7/16″ which is a little over 11 mm. Make sure to check your hasp opening size because while this is a great lock for storage units, it’s not compatible with all facilities.

Finally, it’s important to consider that this lock has an ASTM security grade of 5, which is good, but not quite on par with ABUS locks that come in with grades of 7 or higher. For people who want a stout lock for an affordable price and aren’t locking up anything too valuable, this lock will get the job done. It’s also a good choice for folks who are renting indoor storage units that provide additional layers of security.


  • A good budget alternative to ABUS Granit locks
  • The 6-pin cylinder with anti-pick pins is harder to pick than cheap disc locks
  • Well-built and stout for the price
  • Spool pins for anti-bump protection
  • A good choice for outdoor storage units


  • 7/16″ shackle diameter is not compatible with all storage facilities
  • Easier to duplicate the keys than ABUS or Medeco
  • More prone to corrosion than other locks in our guide

#5) Master Lock 40DPF Stainless Steel Discus Padlock

For people who are storing low-value items and need a basic disc lock that gets the job done, Master Lock’s 40DPF lock is a good choice. Unlike several locks in our guide, the 3/8″ shackle diameter is more universal, so there’s a very slim chance you’ll run into any sizing issues. The lock itself is made of stainless steel with a hardened steel shackle. This combo is enough to secure your belongings, especially if you’re renting an indoor unit.

A couple of things to keep in mind are that the 4-pin cylinder is the easiest to pick of the locks in this guide, and the keys are easy to duplicate. For these reasons, we don’t recommend using this lock to secure your treasured possessions, especially considering the Stanley lock above doesn’t cost too much more at the time of this writing.

The good news is this lock blends in the best of the locks in this guide and is very unlikely to draw attention. If you think about it this way, in the event a thief does infiltrate your facility, he or she is likely to skip over a small storage unit with a cheap Master Lock. Plus, considering the hasp is sometimes the weakest link at a storage facility, even the best lock won’t keep out a determined thief.


  • The best cheap disc lock for storage units
  • Universal fit to avoid sizing issues
  • Enough lock to use at storage facilities with good in-house security
  • Suitable for use on small indoor units to store low-value possessions while moving
  • Disc locks are inherently harder to cut since it’s difficult to access the shackle


  • The least secure of the five locks in our guide
  • A 4-pin cylinder is easier to pick
  • Does not hold up as well in outdoor environments with harsh winters

Final Tips

While these are the best padlocks for storage units, there are additional precautions to take when selecting a unit. First, it’s important to get a feel for the integrity of the storage facility employees when checking out the units. Do your best to get a feel for the environment and the people who work there. Are there a lot of teenagers working there? Is it a family-owned facility with a trustworthy group of people running it? The latter is a better option.

Additionally, it’s wise to ensure the facility has a reliable security camera system. Lastly, if you’re planning to store valuable possessions and can swing an indoor unit, it’s always nice to get an indoor locker that requires a code or has additional layers of security to enter the building. A lot of facilities have elevators to make carrying heavy items upstairs easier. Plus, indoor units can be more insulated than outdoor units if you’re storing temperature-sensitive items.

By choosing a good facility and one of the locks in this guide, you give yourself the best chance of avoiding theft and getting that invaluable peace of mind we all love so much.

Jump Back to Top 5 Chart

Related Posts