A small knife is one of the most useful things you can carry with you. If it’s small enough, you can even hang it off your house and car keys—or use it to hold those keys itself.
There’s a remarkable variety of knife designs out there, and keychain-sized knives are no exception. Here are ten of the best that we’ve been able to find.
The Best Overall Keychain Knife: KeySmart Dapper 100 Keychain
If you want a blade more than anything else, along with a classic but compact style, this stainless steel design is durable and won’t draw attention. The blade folds down to 2.5 inches and comes with a wide loop for attaching directly to keys or a ring. It’s also surprisingly light at around one ounce, not to mention very affordable.
KeySmart Dapper 100 - Ultra Slim Keychain Gentleman's Knife
The Keysmart Dapper 100 is an excellent pocket knife small enough to hang on your keychain.
For Those Who Appreciate the Classics: Victorinox Swiss Army Classic SD
The original Swiss Army knife has been around for over a century thanks to its compact build and versatility. The long-running Classic SD model is small and light enough to hang from your keys while keeping a small blade, scissors, nail file, flathead screwdriver, tweezers, and a toothpick, all in under an ounce of weight. It’s available in over a dozen colors and finishes.
Victorinox Swiss Army Classic SD Pocket Knife, Black, 58mm
There Victorinox Classic SD has everything you want in a smaller Swiss Army knife.
For the Thinnest Blade Possible: SOG Keychain
If you’re after the absolute minimal thickness in your keychain knife, SOG has been making insanely thin folders for years. This one includes an integrated easy-open key ring and a bottle opener on the opening mechanism, with a special highlight being a user-adjustable tension spring.
SOG Keychain Pocket Knife with Bottle Opener Keychain Ring - Keytron EDC Keychain Knife with 1.8 Inch Folding Knife
This SOG folding knife is razor-thin. Pardon the pun.
For a Reliable Fixed Blade: Tonife Full Tang Neck Knife
Those who need knives with more stability and reliability can’t rely on folders. The Tonife fixed blade is under two inches but comes with a rigid textured handle and a protective sheath made of tough Kydex material. Keys can be attached on the large ring on the handle, with enough space for most users to get a good grip.
TONIFE Fixed Blade Neck Knife Full Tang 4-5/8 Inch Overall with Kydex Sheath and Ball Chain (Black)
This fixed blade is just small enough for a keychain and includes a separate Kydex sheath.
For a Tough Folder: Kershaw Cinder
Kershaw’s folding knives are among the best sellers on the market, and for a good reason: they’re reliable and sport excellent action. the Pub model integrates a loop for sticking on your keychain and a bottle opener-slash-screwdriver thing, with a short straight blade reminiscent of a box opener.
Kershaw Cinder (1025X) Multifunction Pocket Knife, 1.4-inch High Performance 3Cr13 Steel Blade with Stonewashed Finish, Glass Filled Nylon Handle, Liner Lock, Bottle Opener, Lanyard Hole, 0.9 OZ
This Kershaw model can take a beating while still preserving all the essential folder functions.
For a Subtle Hidden Tool: Mehr Classic Key Chain
Sometimes it’s not good to advertise. This carabiner-style keychain hides a tiny folding knife and a Swiss Army-style bottle opener/file/screwdriver in the steel housing. It’s surprisingly slick for such an inexpensive item. Just make sure to leave it at home where knives are fully banned, like airports.
Mehr Classic Attachable Key Chain - Simple, Elegant, Durable Multi-Ring Key Holder - Smart Keychain (Silver - Knife, Bottle Opener)
This carabiner hides a tiny pocket knife in its metal frame.
For a Thin Serrated Blade: MAXERI Knife
If you often cut through tough rope or similar materials, you’ll want a serrated section on your knife. This small blade includes serration, and its minimal frame is lightweight for a blade around two inches. The blade locks to the frame, and you have the option of carrying with a pocket clip if you don’t like the keyhole.
MAXERI World's Smallest All Purpose Pocket Knife, Premium Heat Treated Stainless Steel Blade, Micro Concealable Minimalist Design, The Ideal EDC Knife
This super-sleek model includes a serrated portion on its blade, ideal for cutting ropes and tough materials.
For Discretion: Porter Key Knife
This tiny knife hides among your keys, folding out on a rigid hinge to reveal a 1.2-inch straight blade perfect for opening letters and boxes. When folded, it includes a handy bottle opener. This is another one that needs to be taken off your keychain on the way to the airport. The manufacturer includes a high-quality cable keyring with the knife.
For the Tiniest Folder Possible: Gerber GDC Zip Blade
This thing’s so small you’d barely know it’s a knife, but it’s a fully-functional folder from a reliable brand. At under .7 inches with a frame lock function, it’s a great little tool if you need absolutely the smallest thing possible. Note that its key loop is fabric, so this one may be less reliable (and more susceptible to being lost) than the other knives on this list.
Gerber GDC Zip Blade [31-001742]
This absolutely tiny Gerber blade is under one inch, but manages to include a locking mechanism anyway.
For Maximum Flexibility: Leatherman Squirt PS4
This double-folding tool includes the standard 1.6-inch pocket knife, plus tiny pliers, scissors, wire cutters, and multiple files and screwdrivers. At two ounces it’s one of the heavier and bulkier options on this list, but no other tool does so much with so little space. It comes in red, black, and blue.
LEATHERMAN, Squirt PS4 Keychain Multitool with Spring-Action Scissors and Aluminum Handles, Built in the USA, Red
This flexible Leatherman tool includes an impressive array of fold-out capabilities.