How Much Are Lawn Mower Blades?

Is your lawnmower not cutting like it used to? Thinking of sharpening the blades or possibly getting new ones? Wondering how much are lawn mower blades?

Lawn mower blades range in price from $14 – $25 dollars. You should sharpen your blade every 25 hours. Low cost blades last 100-200 hours. Higher cost high end blades can last 300-400 hours. After this time the blades should be replaced. If it takes you 1 hour per week to mow your lawn then sharpen the blades once at the beginning of each season (30 sessions/hours) and replace the blade after 4 years (120 sessions/hours). High end blades may last another 4 years using this example.

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How Long Do Lawn Mower Blades Last?

Lawn mower blades last approximately 100 up to 400 hours of use. The lower range is for lower cost blades and assume you end up hitting lots of rocks. The higher range is for higher quality blades and assumes you avoid the rocks.

Maxpower 331528B Mulching Blade for 21 Inch Cut MTD/Cub Cadet/Troy-Bilt Replaces 742-04100, 742-0741, 742-0741A, 942-0741, 942-0741A

How Do I Know If My Mower Blade Is Dull?

Run this quick test to see if it’s time to sharpen the blade. It’s best to do this manual check every two months even if the math says you can go a bit longer.

  1. Are there a lot of nicks and cuts in the blade from hitting rocks and objects?
  2. Check the grass after you mow. Are the ends cleanly cut or do they have jagged ends?

If the blades aren’t cutting the grass cleanly and if they have a lot of nicks or damage it’s time to sharpen the blade.

Should I Sharpen My Lawn Mower Blade Or Buy A New One?

A better question is how much is your time worth?

It costs roughly $25 to get a new blade. Assume you’ve replace it before and it takes you about an hour of your time to change it out. Also assume your order the blade off Amazon and avoid any time going to the store and back.

Total time and cost to replace a blade: $25 plus 1 hour of time.

Now let’s consider sharpening the blade. It takes 40-50 strokes of a file in working order to sharpen each side of a blade. That should take you about 15 minutes. We also have to throw in the same hour to take off the blade and put it back on. This assumes your time to replace a blade is roughly the same time to take off an old blade a put it back on. That adds up to 1.25 hours total time.

For this example we’ll also assume you have a working file and don’t have to buy one.

Total time and cost to sharpen a blade: $0 plus 1.25 hours

Let’s assume you make $20 per hour so we can normalize this by converting all the time into money for a true side by side comparison.

Replacing a blade cost: $25 + (1 hr * $20) = $45

Sharpening a blade cost: $0 + (1.25 hr * $20) = $25

But what if you make less money? More money? Let’s run a quick table to quickly see which is better – to buy or to sharpen.

The results are in. No matter your wage it’s cheaper to sharpen. Of course, you’ll note in the table above that as your wage goes up the gap between sharpening and buying is less. At some point you can pay someone to either sharpen or change out the blade. By that time you likely aren’t mowing your own yard anymore.

How Do I Know If I Need A New Lawn Mower Blade?

If there are nicks and damage on the edge of the blade and if freshly cut grass doesn’t have a cleanly cut edge but is instead jagged, then it’s time to sharpen or buy a new lawnmower blade.

If you’ve gone through four rounds of sharpening it’s probably time for a new lawnmower blade.

In the end the true test is how well it’s cutting the grass.

Are Mower Blades Universal?

At first it seemed like mower blades were universal. I did a little digging and checked with a mechanic.

No, lawn mower blades are not universal. You must get the right size with the correct specifications for your make and model of lawn mower. The specifications include the torque required by your manufacturer. This is key so the new blade doesn’t damage your lawn mower while in use or worse, come flying off.

How To Identify Which Lawn Mower Blade You Need

  1. Check the make and model of your lawn mower or the part number of your blade.
    • You can find the make and model of your lawn mower on the body. If you have an older lawn mower and this has worn off you have a few options.
    • First, check the mower blade. It should be stamped with a model number. That’s the best method.
    • Second, scan through pictures on Amazon or Google shopping to try and identify it.
    • Third, if the above fail go to a lawn mower forum, submit a picture, and ask the forum members if they can help you identify it and what blade you need.
  2. If the above fails you’ll move on to trying to identify which blade directly from the blade itself. First take some measurements. These measurements are absolutely key. Do them incorrectly and you could damage your lawn mower.
    • Use a good rule for this. You may even need special measuring calipers. Getting these right is extremely important.
    • First measure the length of the blade
    • Next measure the diameter of the center hole. This must be an exact fit. If the hole is too large the blade will wobble while in use.
    • Then measure the length of the shear pin holes (the holes on both sides of the center hole). You want the length from the outer edge of one hole to the outer end of the other.
  3. Next, determine if it’s a mowing blade (2 in 1 – cut then lift) or a mulching blade (3 in 1 – cut, lift, mulch). A mowing blade (2 in 1 – cut then lift) or a mulching blade (3 in 1 – cut, lift, mulch). Mowing blades are designed to cut then lift the grass and throw it into a side bin (or back on the grass). They have wide wings and short cutting edges. Mulching blades are designed to cut then mulch the grass. They have shorter wings and curved edges meant to lift and mulch the grass.

Types Of Lawn Mower Blade – Mulching Blades vs Mowing Blades

There are two main types of lawnmower blades:

  • 2 in 1 Blades – Mowing Blades – These are meant to cut and lift the grass into a catchment bag. The edge of the blade will be straight.
  • 3 in 1 Blades – Mulching Blades – These are meant to cut, lift, and mulch then leave the highly chopped grass mulch in place. The edge of the blade will be curved.

Can You Put Mulching Blades On Any Mower?

Yes, you can put a mulching blade on any mower as long as the center and shear pin holes have the same measurements as those on the blade that came with your mower.

What Is A 3 In 1 Mower Blade?

A 3 in 1 mower blade is a mulching blade. It cuts, lifts, then mulches (the 3 actions).

Aftermarket Lawn Mower Blades Cost

After market blades (off-brand) tend to be $5 – $10 cheaper than brand name blades. Some have longer shear pin holes that make it easier to attach the blade to many different types of lawnmowers.

It’s important that the center hole is still the exact same size as the blade that came with your mower. You don’t want an oversized hole that would cause the blade to wobble while in use.

Arnold 490-100-005621-Inch Deluxe Universal Detaching Blade for Walk-Behind Mowers