Out-the-front knives are sold by overall length, but the number that matters most is blade length: it decides what the knife can cut and, in many places, where you may carry it. This guide lays out the three size classes on this site with the blade and overall lengths of the knives actually in stock, so you can pick a class before you pick a knife. The full range is on the OTF knives collection.
OTF size chart
| Class | Overall length | Blade length | Typical weight | In stock | Best for |
|---|---|---|---|---|---|
| Micro / mini | 5 to 5.5 in | 1.75 to 2 in | 1 to 2.5 oz | 65 | Keychain, gift, first OTF |
| Compact | 6.75 to 7 in | 2.5 to 2.625 in | 2.5 to 3.5 oz | 30 | Low-profile pocket carry |
| EDC / mid-size | 7.25 to 8.25 in | 3 to 3.25 in | 3 to 4.5 oz | 66 | Daily carry with a clip |
| Full-size / tactical | 8.5 to 9.75 in | 3.5 to 4 in | 4.5 to 7 oz | 95 | Bag or belt, hard use |
| XL | 10 to 11 in | 4.25 to 4.75 in | 7 oz and up | 5 | Display, collection |
Counts are in-stock models on the day of writing. Weights are ranges from the listings that state them; not every product page lists weight.
Mini and micro (5 to 5.5 inches)
Blades under 2 inches, handles the length of a car key. These are the best-selling knives on the site because they are cheap, clip to a coin pocket and fire the same way the big ones do. They are utility edges, not work knives. Ranked in best mini OTF knives.
Compact (6.75 to 7 inches)
A 2.5-inch blade in a handle that still disappears in a front pocket. The Patriot Shadow and Shadow Banner (double-action tantos) and the Shadowline Discreet Operator (single-action spear point) are the most-ordered. This is the class for someone who wants a real blade with the least handle.
EDC and mid-size (7.25 to 8.25 inches)
The 3-inch blade class and the middle of the market. Almost every handle material and both mechanisms are available here, and it is where the best-selling double action on the site lives. Ranked in best EDC OTF knives.
Full-size and tactical (8.5 to 9.75 inches)
Blades from 3.5 to 4 inches and handles built for a full grip. The largest class by count and the one people mean by "tactical OTF". Heavier springs, louder deployment, and the most tanto blades. Ranked in best tactical OTF knives.
XL (10 inches and up)
Five knives: the 10.5-inch Redline Weave XL, the 10-inch Stealth Carbon Fusion knuckle knife, and the 11-inch Heritage Stiletto among them. These are collection pieces; the blade lengths put them outside most carry thresholds.
Blade length and carry rules
Many jurisdictions set a blade-length threshold for automatic knives, and 2 inches is one that comes up often, which is why the mini class is marketed as compliant in some places. This site does not give legal advice. The state-by-state automatic knife guide on Self Defense Supply lists each state's rules with statute citations; read it before choosing a class.
Frequently asked questions
What size OTF knife should I get?
For a keychain or gift, a mini. For daily carry, 7.25 to 8.25 inches with a clip. For a bag or belt knife, 8.5 to 9.75 inches.
How is OTF blade length measured?
From the tip to where the blade enters the handle opening when fully deployed. Overall length is tip to butt with the blade out.
What is the biggest OTF knife?
On this site, the Heritage Stiletto at 11 inches overall with a 4.75-inch blade.
Prices are the bestotfknives.com prices at the time of writing and change with stock. Automatic-knife rules differ by jurisdiction; before ordering, read the state-by-state automatic knife guide and check your local rules.