The WORKPRO 18mm Retractable Utility Knife with 10-Piece SK5 Blades is a snap-off box cutter for opening cartons and cutting cardboard. It is aimed at home, office and light shop use. My verdict: a simple, sensible knife that covers everyday cutting.
The blade is 18mm SK5 steel, listed for good edge retention. Ten extra blades come in the box and each has 8 snap-off segments, so you break off a dull tip and keep working. It is 6.5 inches long and 0.16 pounds with an aluminum alloy shell, so it carries easily in a toolbox.
Quick verdict: A light, well-stocked snap-off knife for everyday box and cardboard cutting.
- Best for: Cartons, cardboard, foam board and craft work.
- Skip it if: You need a knife for prying or scraping, since a snap-off blade is not made for that.
- Key spec: 18mm SK5 steel blades, with 10 extra blades of 8 segments each.
WORKPRO 18mm Utility Knife Specs and What Comes in the Box
This knife is 6.5 inches long and weighs 0.16 pounds, so it rides in a pocket or tool bag without much notice. The shell is aluminum alloy with ABS plastic. Metal adds rigidity and the plastic keeps the weight down.
- Blade width: 18 mm
- Blade steel: SK5
- Spare blades: 10 included, each made up of 8 detachable segments
- Safety: automatic safety lock plate
- Slider: sized for one-handed operation
In the box, the WORKPRO 18mm Retractable Utility Knife with 10-Piece SK5 Blades gives you the knife and the extra blades. That is a lot of fresh edges before you need to reorder anything. When a segment goes dull, you snap it off along the scored line using the plastic groove at the bottom of the handle. A wide 18 mm blade is the usual choice for cardboard, foam board and heavier cutting, since it gives you more blade to work with than the small craft knives do.
How Sharp and Durable Are the SK5 Blades?
The listing credits the SK5 steel with better edge retention, thickness, sharpness and durability. Reviewers back that up on sharpness. Of the 30 who mention it, 26 are positive and 4 are negative. Buyers describe clean cuts through cardboard and foamand one says the blades are sharp and stay sharp.
On a snap-off knife, how fast you can get a fresh edge matters as much as how long one edge lasts. Each blade has 8 detachable segmentsand you snap off a worn one along the scored line using the plastic groove at the bottom. With 10 blades in the pack, that is a lot of fresh points. One reviewer says the blades are lasting a long time.
- Stiffness: one reviewer says the heavy-duty blades have very little flex, which helps on straight cuts.
- Snapping: another says the blades do not snap off easily by accident, unlike cheaper ones they have used.
- Rust: one buyer warns the blades can rust, so keep them dry.
That rust note matters if the knife rides in a damp toolbox or truck. Wipe the blade down and store it dry.
Is the WORKPRO Knife Tough Enough for Daily Jobsite Use?
Build quality is the strongest point here. The shell is aluminum alloy with ABS plastic, the knife is 6.5 inches long and it weighs 0.16 pounds. Of the 79 reviewers who mentioned quality, 78 were positive. Several called it sturdy and said it does not feel like a plastic knife.
Blade locking is where I would pay attention. The listing describes an automatic safety lock plateand 12 of 15 reviewers liked how it opens, closes and holds. Three were negativeand one said there is no way to lock the blade in place while in use. That matters on any retractable knife when you lean into a cut.
The blades are 18 mm SK5 steeland each one has 8 detachable segments you snap off when the tip dulls. That is a practical setup for daily cutting of cardboard, plastic and foam board. One reviewer warned the blades can rust, so keep them dry. When it arrives, check these things:
- Push sideways on the extended blade to feel for wobble.
- Snap off a segment using the plastic groove at the bottom.
- Test the slider with one hand and a glove on.
- Store spare blades dry.
Which 18mm Replacement Blades Fit This Knife?
The blade that fits this knife is an 18 mm snap-off blade. The WORKPRO 18mm Retractable Utility Knife ships with 10 extra bladesand each blade has 8 detachable sections. That is 80 fresh working points before you need to buy anything.
The description does not list compatible brands or part numbers, so I won’t tell you a specific brand fits. Before you buy a bulk pack, check these points:
- Width: It has to be 18 mm. A 9 mm or 25 mm blade is a different knife.
- Style: Look for segmented snap-off blades with scored break lines, like the ones included.
- Steel: The included blades are SK5 steel. Matching it keeps edge retention in the same range.
- Return window: Buy a small pack first if you can. Bulk boxes are a hassle to send back.
On the job, a blade that is slightly off in width or thickness will rattle in the slot or bind in the slider. That is annoying at best and unsafe at worst. Snap off dull sections along the score line with the plastic groove at the bottom of the handle. Don’t use pliers on it.
How Does WORKPRO Compare With a Stanley 18mm Knife?
The biggest difference is what comes in the box. This WORKPRO ships with 10 bladesand each blade has 8 detachable segments. That is a lot of fresh edges before you buy anything else. I won’t quote Stanley specs here because they vary by model, so check the one you are comparing against.
On build, the WORKPRO has an aluminum alloy shell with ABS plastic, runs 6.5 inches long and weighs 0.16 pounds. The blades are SK5 steel. Reviewers describe it as solid without being too heavy, but 3 of 15 who mentioned blade locking were unhappy with it. One said there is no way to lock the blade in place while cutting.
If you are choosing between the two, put them side by side and check these:
- Blade wobble: push sideways on a scrap cut and see how much play there is.
- Slider feel: the description says it is sized for one-handed use, so test it with gloves on.
- Blade changes: the WORKPRO snaps off worn segments using a plastic groove at the bottom.
- Rust: one reviewer said the blades can rust, so keep them dry in the truck.
Which Jobs and Users Suit This Knife Best?
This knife fits best on cardboard, cartons and boxes, plus lighter material like paper, foam board, plastic and fabric. That is what the 18mm SK5 blade is described for. Reviewers mention breaking down boxes, cutting foam and building cardboard props and costumes.
- Box and carton work in an office, shop or home
- Foam and foam board where a sharp, fresh edge matters
- Crafts and DIY, where the snap-off segments give you a new point fast
- Toolbox or wall storage as a light general knife at 6.5 inches and 0.16 pounds
- One-handed use, since the slider is sized for your finger
I would be more careful with it for hard, repeated pressure cuts. The WORKPRO 18mm Retractable Utility Knife has an automatic safety lock plate, but one reviewer said there is no way to lock the blade in place while cutting. Three of the 15 reviewers who mentioned blade locking were negative. When I push through thick material, I want zero blade shift, so keep that in mind.
Also think about upkeep. Snapping off a dull segment takes a stepand one reviewer found removing the end piece awkward. Another said the blades can rust, so keep them dry.
Pros & Cons
Pros and Cons
| Pros | Cons |
|---|---|
| 18mm SK5 steel blades, listed for edge retention and sharpness | One reviewer says there is no way to lock the blade while cutting |
| Ten extra blades included, each with 8 snap-off segments | Snapping off a dull segment with the end groove is awkward, per one reviewer |
| Weighs 0.16 pounds and measures 6.5 inches long | Reviewers report minimal blade wobble, so it is not zero |
| Automatic safety lock plate and a slider sized for one-handed use | One reviewer warns the blades can rust, so they need to stay dry |
| Aluminum alloy shell with ABS plasticand reviewers like the weight | Shell is part plastic, which matters if you want an all-metal body |
Skip it if: you want a positive manual blade lock for heavy scoring work, an all-metal bodyor a knife that lives in a damp toolbox without blade care.
Frequently Asked Questions
Does the WORKPRO 18mm retractable utility knife come with extra blades?
Yes, the listing says it includes 10 extra SK5 blades. Each blade is made of 8 detachable small segments, so you snap off a worn section along the scratch line using the plastic groove at the bottom. Check the listing to confirm exactly what ships with your order.
Is the WORKPRO 18mm utility knife good for cutting cardboard?
Yes, the listing names cartons, cardboard and boxes as intended jobsand reviewers mention cutting cardboard and opening boxes. The 18 mm blade is SK5 steel. It also lists paper, photos, plastic, fabric and foam board. On any knife, a dull edge drags and slips, so snap off a worn segment early.
Does the WORKPRO retractable utility knife lock the blade?
It has an automatic safety lock plate according to the listing, but one reviewer says there is no way to lock the blade in place while in use. Of 15 reviewers who mention blade locking, 12 were positive and 3 negative. Another said blade wobble is minimal. Check for play before you lean into a heavy cut.
How long and heavy is the WORKPRO 18mm retractable utility knife?
It is 6.5 inches long and weighs 0.16 pounds, according to the listing. The shell is aluminum alloy and ABS plastic. The slider is sized for your finger so you can work one-handed. Reviewers describe it as solid without being too heavy. It can hang on a wall or sit in a toolbox.
Do the SK5 blades on the WORKPRO utility knife rust?
One reviewer says the blades can rust, so keep them dry. The listing describes the blades as SK5 steel but says nothing about corrosion resistance or coating. Wipe the knife down after damp work and store it dry. Check the listing or WORKPRO if you need details on blade finish.
Final Verdict
This is a simple snap-off knife with plenty of spare bladesand that is the point. The description lists an 18mm SK5 blade, an aluminum alloy and ABS body, 6.5 inches of length and 0.16 pounds. Buyers lean positive on quality, sharpness and easy blade swaps. A few flagged the blade lock and the awkward snap-off stepand one said the blades can rust if left damp. Keep it dry and that is minor.
It suits homeowners and DIYers who cut cardboard, foam, fabric and craft materials. It also works as a spare in a tool bag. If you are a pro who runs a knife all dayor you want a positive lock on the blade while cutting, look at a fixed blade or lever lock model with a heavier build. For boxes and shop odds and ends, this is a low-risk buy.