Irwin box cutter with new blade and arrow representing a blade change

How To Change Box Cutter Blade (With pictures!)

Box cutters, also known as utility knives are very useful tools. They are compact and can be used for a variety of different projects. They have the ability to cut cardboard, drywall, thin wood and everything in between.

Depending on what you are cutting with your box cutter the blades dull fairly quickly. So blade changes need to happen frequently in order to maintain a sharp blade. I will show you step by step how to change the blade on you box cutter.

How to change box cutter blade

To change the blade on a box cutter first access the new blades. Move the blade button to the unlocked position. Press the quick release button and pull blade out. Slide new blade in until it locks in place. Ensure it’s locked in by protracting/retracting blade. Discard old blade.

Irwin utility knife

Key parts of box cutter

Irwin box cutter with key parts labeled
  1. Blade
  2. Quick change blade mechanism
  3. Blade protractor/retractor button
  4. Hinged blade storage
  5. Blade storage button

Step 1: Access new blades

The first step to changing your box cutters blade is accessing the replacement blade. Most knives have some form of storage unit in the handle of the knife. Before doing anything though it is important to note: the blade should remain retracted during this first step!

To unlock the blade storage on the Irwin utility knife press the yellow button on the end of the knife. When you do this the hinged blade storage will pop open.

Pressing the yellow blade storage button on an Irwin box cutter

Now you can pull the hinged blade storage piece out to access the new blades. Remove one of the blades and then close the blade storage compartment. When doing this you should hear a click when the button snaps into the locked position.

Opening up the blade storage compartment on an Irwin box cutter

If your box cutter does not have a blade storage compartment then grab a new blade from storage or go to the local hardware store to grab some new blades.

It is important to note, be very careful when handling these box cutter blades. They are very sharp and can easily cut you. You should always handle the blades from the top, opposite of the sharp blade.

Holding a box cutter blade from the top

Now that the new blade is close by and ready to go, lets move on to the next step.

Step 2: Unlock the current blade

It is important to note that in this step it will be a little different for each box cutter depending on the brand. With that being said most newer models have some type of quick release blade button.

For my Irwin, to unlock the blade you have to slide the blade retractor/protractor button forward. Do so until the small groove in the middle of the silver blade button, lines up with the groove on the box cutter. It is marked with a yellow line on the box cutter.

Box cutter grooves lined up so blade is unlocked

Once these two grooves are lined up the blade is set in the proper position. Move on to the next step.

Step 3: Remove the old blade

There is not much of the blade showing in this unlocked position so be very careful when grabbing the blade. Even though the blade is likely dulled, it is still sharp enough to cut you.

Small amount of blade showing when in unlocked position during blade change on box cutter

With that safety notice taken care of, now lets remove the blade. To do so simply press the yellow quick change blade button and hold it down. With that button held use your other hand to slide the blade out.

Siding box cutter blade out while holding quick release button

The blade should slide out very easily. If you meet any resistance when pulling the blade out stop and reset. It may be that you are not pressing the yellow button down enough. Make sure to keep holding the blade release button down until the blade is fully removed.

Arrow representing direction to pull blade when removing from box cutter

Once the blade is fully removed you can release the yellow button. Make sure to dispose of the old blade in a safe place. I like to place mine in a plastic bottle and then put it in recycling.

Blade removed from box cutter

Step 4: Insert the new blade

Prior to inserting the new blade make sure that the two grooves that you lined up in step 2 are still in line. Sometimes during the blade removal they will no longer be lined up.

Now once again press the yellow quick change button. Holding the blade from the top, slide it into the slit. Keep sliding it down until it locks into place. You will hear a click once it has been locked in.

Putting new blade in irwin box cutter

The lock position of the blade will be with about 3/4ths of an inch of the blade showing. Once you hear the click and you think the blade is locked in, release the yellow button.

3/4th inch of blade showing when replaced on box cutter

Step 5: Protract and retract the blade

The final step is to make sure the utility knife works with the new blade. You want to make sure the protract/retract button slides nice and smoothly. When sliding the button the blade should slide forward and back with no resistance.

Using silver button to protract and retract blade on box cutter

If the blade is not in the correct position the button will not slide smoothly or not slide up and down at all. If this is the case remove the blade and return to step 4.

Other brands

As I have mentioned before there are a number of different style and brands of box cutters out there. Each one will be a little different when it comes to changing the blade.

Different brands and styles of box cutters

Per the New York Times after testing many different types of cutters they claim the best one out there is Milwaukee Fastback utility knife. Each and every brand puts a little twist on there version but for the most part they are all pretty similar. The best part is that the blade shape is universal for all utility knives.

Older utility knives

My Irwin utility knife is a newer model. You can tell you have a newer model if they have the quick blade change button. Older box cutters did not have this feature. Most older box cutters were also straight and did not have the curved shape the newer models have today.

Old box cutter vs new box cutter

If you have an older model box cutter do not worry, I have you covered to. The blade change process is slightly different and only a little more time consuming. It requires the removal of the retaining screw.

Reasons to change blade

There are a number of reasons why you may need to change your box cutters blade. Depending on what you are cutting will determine how long the blade lasts. Reasons to change the blade include; blade is dull, blade broke, corner of blade is chipped, etc. How I determine it is time for a new blade is by looking at the corner of the blade. If it is squared off at all and no longer pointy then I know it is time for a new blade.

Dull vs sharp blade shown

The beauty of the box cutter blades though is that each end is a different cutting blade. So with each blade you get 2 cutting ends. When changing the blade if the other side has not been used yet you can just flip the blade over to access the other end.

Showing 2 different cutting sides on single blade.


Changing the blade on a box cutter can be difficult and dangerous if you do not know what you are doing. Make sure you follow these 5 steps when changing the blade on your box cutter.

  • Key parts of box cutter
  • Step 1: Access new blades
  • Step 2: Unlock the current blade
  • Step 3: Remove the old blade
  • Step 4: Insert the new blade
  • Step 5: Protract and retract the blade
  • Other brands
  • Older utility knives
  • Reasons to change the blade

I hope you found this helpful. If so I would love to hear about it in the comments.

Leave a Reply

Your email address will not be published.