What Blade Length Should Your OTF Knife Be? 1.85, 3.5 or 3.8 Inches, and How to Choose

The Short Answer

Blade length on an out-the-front knife is not the same decision as blade length on a folder, for one reason: the blade has to fit inside the handle twice over, once retracted and once in the travel of the mechanism. That makes an OTF's handle longer than a folder's for the same blade, and it means that choosing a blade length is also choosing a handle length, an open length, a weight and, in a handful of states, whether the knife is legal to carry at all. This guide walks through what each size does well, what it costs you in the pocket, where the law draws its lines, and which TEKTO OTF fits each answer. The numbers are from our own spec sheets. The law is from the state pages we maintain, each verified against the statute.

Why Length Matters More on an OTF

A folding knife hides its blade in the handle by rotating it. The handle only needs to be a little longer than the blade. An OTF hides its blade by pulling it straight back, so the handle must hold the whole blade plus the carriage and spring that drive it. On our OTFs the handle is the blade length plus 1.3 to 1.6 inches: the 3.50-inch A5 Spry rides in a 4.90-inch handle, the 1.85-inch A5 Spry Mini in a 3.20-inch one, the 3.80-inch A4 in a 5.40-inch one. Open, that is 8.4 to 9.3 inches of knife for the full-size models and about 5 inches for the small ones. Weight follows the same curve, and faster, because the handle is aluminum around a steel carriage: 2.15 ounces for the Spry Mini, 3.49 for the Spry, 3.70 for the A7 Zastava, 5.40 for the A4. The difference between the two ends of that range is the difference between a knife you forget is in your pocket and one you notice every time you sit down. None of this is a flaw. It is the price of a blade that deploys and retracts in a straight line with one thumb. It just means that an extra half inch of blade on an OTF costs more than it does on a folder, and you should want it for a reason.

The TEKTO OTFs by the Numbers

Two automatics that are not OTFs sit alongside these for anyone comparing: the side-opening A3 Delta, a 3.60-inch D2 drop point at 5.96 ounces, and the A3 Delta Mini, 1.90 inches and 2.54 ounces. A side-opener folds, so its handle is shorter for the blade (4.00 inches on the Mini) but its action swings rather than slides. Every knife in the table is a button lock. The OTFs are double action, meaning the same slide extends and retracts the blade.

Under 2 Inches: The Legal Size

The 1.85-inch OTF is a category because of one sentence in California law. Penal Code 17235 defines a switchblade as a knife with a blade "two or more inches in length" that opens automatically, and 21510 makes carrying, selling or lending one a misdemeanor. An automatic with a blade under 2 inches is outside the definition and legal to carry anywhere in the state that allows a knife at all. Older guides put the line at two and a half inches, which would have made a 2.25-inch OTF legal in Los Angeles. It is not. Our California page has the statute text. The short version is that the A2 Badger, the A5 Spry Mini and the A3 Delta Mini are the three TEKTO automatics built for it, at 1.85, 1.85 and 1.90 inches, and nothing else we make is. California is the biggest reason to buy small but not the only one. Mobile, Alabama is reported to require disclosing any knife over 2 inches to an officer, and Montgomery to cap blades at 3. A few other cities draw lines of their own. And a 1.85-inch blade is a better everyday cutter than its size suggests: it opens every box, cuts every zip tie and strap, trims a line, sharpens a pencil and slices an apple, and it does all of that from a handle that weighs about as much as a car key and sits flat in a shirt pocket. The Spry Mini adds a tungsten glass breaker for the one job a short blade cannot do. What it will not do is reach into a deep box or break down a cardboard pile quickly, and it is not the knife for a campsite kitchen. If your knife lives on a keychain or in a suit pocket, under 2 inches is the right answer regardless of where you live.

Three and a Half Inches: The Everyday Size

Most of the OTF market lives between 3.25 and 3.75 inches, and so do we: the A5 Spry at 3.50 and the A7 Zastava at 3.60. This is the length at which the blade stops being a box cutter and starts being a knife. A 3.5-inch edge has enough belly to slice rather than saw, enough reach to cut through a double-wall carton in one pass, and enough tip to do food prep or whittle a feather stick at a campsite. The handle that comes with it, 4.90 inches, fills the hand, which matters for an OTF more than for a folder because the deploying thumb needs purchase and the fingers need something to hold while it slides. At 3.49 ounces the Spry is light for a full-size automatic, and it rides in a jeans pocket on its clip without printing. The Zastava is the same size with a double-edged spear point and wood inlays, a knife for the collector who still wants to carry it. For the great majority of people in the great majority of states, this is the size to buy: legal almost everywhere an automatic is legal, big enough for every daily task, small enough to forget. The one check before you buy is your state's blade-length line for concealed carry, covered below, because 3.50 sits on the right side of most of them and 3.60 is a hair over Colorado's.

Over 3.5 Inches: The A4 and When Bigger Makes Sense

The A4 is the largest OTF we make: a 3.80-inch double-edged D2 blade with serrations, in a 5.40-inch handle, 9.30 inches open, 5.40 ounces. That is a knife you carry on purpose. The case for it is reach and leverage: a blade close to 4 inches cuts rope, webbing and hose in one draw, the serrated section saws through fibrous material a plain edge skates on, and the handle gives a gloved hand a full grip. The case against it is the same list read the other way. At 5.4 ounces it is two and a half Spry Minis, the open length is longer than a dinner plate is wide, and a double-edged blade is a dagger in the eyes of several states' statutes, which matters for carry even where automatics are legal. New Jersey, for one, lists daggers among its banned knives, and Texas treats a blade over 5.5 inches as location-restricted. Buy the A4 if you work with rope, webbing or cable, if you want a glove-sized handle, or if you simply want the biggest blade in the line and will carry it where it is lawful. Buy the Spry if you are not sure. The difference in cutting ability on daily tasks is small. The difference in the pocket is not.

Where the Law Draws Its Lines

Blade length shows up in the law in two ways, and the distinction matters. Some rules apply to automatics specifically: California's 2-inch line is the big one, and it is the reason the Badger and Spry Mini exist. Most other length rules apply to any knife carried concealed, automatic or not, and they are the numbers to check before you buy a 3.5-inch OTF for pocket carry. From the state pages we maintain, each verified against the statute: Colorado treats a blade over 3.5 inches as a "knife" that cannot be carried concealed, so the 3.50-inch Spry clears it and the 3.60-inch Zastava does not. Missouri's "ordinary pocketknife" exception stops at 4 inches of blade. Delaware's at 3.75. Minneapolis and St. Paul are reported to draw folding-knife lines at 4 inches. Texas restricts blades over 5.5 inches in listed places. Georgia has nothing to say under 12 inches. None of these is a reason to avoid an OTF, but each is a reason to know your number. The 50-state guide covers whether automatics are legal at all in your state, which is the first question, and the state pages linked at the bottom of this one have the lines and the citations.

How Length Changes the Cut

Length is not only reach. A longer edge has more belly, the curve toward the tip that does the slicing, so a 3.5-inch drop point draws through an apple or a rope where a 1.85-inch blade pushes through in two strokes. A shorter blade gives more tip control, because the point is closer to the fingers. It is the better knife for trimming, scoring and cutting tape along a seam. On an OTF the blade is also a straight bar with no spine curve to speak of, so the edge profile does most of the work: a drop point for general cutting, a tanto for a strong tip that punches through tough material, a double edge for a symmetrical point that pierces easily and gives you a second edge when the first dulls. Blade length changes how those profiles behave. A 1.85-inch tanto is almost all tip, while a 3.80-inch double edge is almost all edge. It also changes sharpening. A short blade is quick to touch up on a rod and awkward on a bench stone. A long one is the reverse. Our sharpening guide covers the 20-degree angle every TEKTO blade leaves the factory with, and it applies at any length.

Picking Yours

1. Start with the law. Check the 50-state guide for whether an automatic is legal where you live and work. If you are in California, stop at 1.85 inches. If your state has a concealed-carry blade line, write it down.
2. Decide where the knife will live. Keychain, shirt pocket or suit: under 2 inches. Jeans pocket on a clip: 3.5 inches. Belt or work bag: anything.
3. Name the three jobs you do most. Boxes, tape and straps: any size. Food, rope, camp chores: 3.5 inches and up. Rope, webbing, hose, gloves: the A4.
4. Pick an edge. Drop point for most people, tanto for tip strength, double edge only where daggers are not restricted.
5. Weigh it in your head. 2.15 ounces disappears. 3.49 is a light full-size knife. 5.40 is a tool you will feel. If you are between two sizes, take the smaller one. Nobody has ever stopped carrying an OTF because it was too light.

TEKTO OTFs by Blade Length

Under 2 inches, the A2 Badger at 1.85 inches in titanium-coated D2 with a carbon fiber and aluminum handle, and the A5 Spry Mini at 1.85 inches in S35VN with a glass breaker, are the California-legal pair. The Badger is the tanto, the Mini comes in drop point, tanto or double edge. At 3.5 inches the A5 Spry is the everyday OTF, in S35VN or, on the Bronze Edition, MagnaCut, with the same three edge options and a 3.49-ounce handle. The A7 Zastava is the 3.60-inch spear point with wood inlays for the shelf that also goes in the pocket. And the A4 is the 3.80-inch double edge with serrations for rope, webbing and gloves. Five knives, three sizes, and the right one is the one that matches your pocket and your state, not the longest one.