How Sharp Should a Lawn Mower Blade Be (For a Great Cut!)

Does a lawnmower blade really have to be sharp?

Grass of any thickness is no match for a blade, especially one rotating at 3000 rpm, no matter how sharp it is, right?

This article will answer some of the most common questions about lawnmower blades like just how sharp they should be.

So you can take your first step towards having a more beautiful lawn!

How Sharp Should a Lawn Mower Blade Be?

Generally, you want your blades to be sharp, but not razor sharp, about the sharpness of a butter knife. Overly sharpened blades tend to dull a lot faster and are a hazard to handle safely as well.

A sharp blade will cut the grass just as well as a razor sharp one. In fact if you sharpen your blade to razor sharpness you will have to sharpen it more frequently making your mower blade last less before you have to get a new one. It’s a fine balance between not making your blade too sharp & fragile so it can actually do its job and having a blade that isn’t sharp enough. In this article we will see what difference does a sharp blade makes,what a sharp blade even looks like and if you need to sharpen new Lawn mower blades any further.

Do sharp mower blades make a difference

Sharpness does matter, think of it like cutting a carrot with a kitchen knife versus a plastic knife. A sharp kitchen knife will provide neat, quick and symmetrical carrot slices. A butter knife not only takes too much unnecessary time and effort, it’ll make sloppy and uneven slices once it finally manages to make a cut. The same principle applies for grass. A dull-edged lawn mower blade will tear up blades of grass rather than making a neat cut like a sharp one would.

Related: When to Replace Lawn Mower Belt

Is mowing with a dull mower blade worth it

No, a dull blade could spell problems for your frontage. Now, if you believe that you have been cutting your grass with a dull blade, don’t panic. Mowing with a less-than-sharp blade a few times is hardly a death sentence for your lawn. However, doing it regularly over a long period of time can have negative effects on your overall turf health, according to The Wykles. In addition to making an ugly-looking, uneven lawn, improperly cut blades of grass are more susceptible to bacteria and fungus, which could lead to yellowing. Also if you are planning to start a Lawn Mowing business ,than a sharp blade is a Must have!

sharp blade difference - how sharp lawnmower blades should be

Do brand new lawn mower blades need to be sharpened?

If you are new to homeowning and are looking to buy your first mower, you might run across some conflicting information on online message boards about whether you should sharpen new lawnmower blades or not.

In general, no, you don’t have to sharpen new blades. If you purchase a lawn mower factory new and according to specifications, the blade should be ready to go. If you do feel the need to sharpen your new blades, you should make sure that the blade is properly balanced before you head out to work, since you don’t end up with a wobbly mower, as this could damage your mower in the long run.

John Deere mower blades

No New John Deere mower blades don’t need to to be sharpened. In fact John Deere has a self-sharpening blade on the market for 60-inch decks, so some of you with riding mowers may not even require sharpening at all.

Honda mower blades

Customers generally report that Honda blades are sharp enough to provide a clean cut as soon as they are purchased,so they don’t need to be sharpened (replacement blades also come cheaper than John Deere).

Husqvarna blades 

No. In fact, Husqvarna specifically asks that you not sharpen their new blades. Their official website claims that “A new blade is precision designed and manufactured for excellent quality of cut and balance.”

Why are some new mower blades not sharp?

Sometimes, brand-new blades will have a coat of paint on the cutting edge that might need to be sharpened off for the best cut, but more often than not, this coat of paint is only thinly applied so customers don’t cut themselves taking a new blade out of the box, so it should flake off after you run the mower for long enough.

In general, check the mower’s instructions and the blade itself (carefully of course, don’t hurt yourself) if you want to play it safe. It also won’t hurt to give the new blade a quick test run in an inconspicuous area if you’re really not sure about its efficacy. However, if you are buying used or borrowing your neighbor’s mower, it’s a good idea to at the very least check the blade to see if it is sharp enough before you mow.

How often should lawn mower blades be sharpened

For a residential setting (that is to say, your front lawn), you should sharpen your blade twice a year, maybe more if you live in a temperate area with a long mowing season. But here’s a solid tip that I learned while working for Josh and Elise Wykle, the owners of Lawn Impressions, a great lawncare business in Mecklenburg, NC, when I was a teen.

If you notice something’s up with the way your mower is cutting, check to see if there’s anything wrong with the blade, even if it’s a bit early. Your blade might be too worn down, it might have sustained some damages, or it might be improperly balanced. It’s better to catch these problems early so they don’t cause sustained damage to your lawn or to your mower.

Also Read: When To STOP Mowing your Lawn in the Fall

What should a sharpened lawn mower blade look like

A sharpened blade has a shiny and bright cutting edge (which is the slanted part, not the back part of the blade. Don’t sharpen the back part of the blade ). Also, when you are sharpening your blades, you want to make sure your blades are free of any major nicks or defects.

Remember, your blades can get damaged should you accidentally run over something hard like a root or a rock (or in my case last year, an old bit of scrap metal hidden in the overgrowth), and these damages can result in an uneven cut no matter how sharp your blades are. Now, smaller nicks can be eliminated with sharpening, but if you see something too major to be fixed when you’re checking your blades, or notice that the quality of your grass is not improving even after sharpening them, you should invest in some new blades.

When should I sharpen my lawn mower blade?

While, like I stated earlier, it’s a good idea to check on your blades as soon as you notice performance issues starting, you should sharpen your blades after every twenty-four hours of mowing. A pretty simple way of figuring out when exactly you have reached twenty-four hours is to time how many minutes it takes to mow your lawn, then divide 1440 (the number of minutes in twenty-four hours) by the number you got. This should give you a solid estimate of how many times you can mow your lawn before the blade needs sharpening.

Also read: Watering lawn after Mowing

Related questions.

How many times can I sharpen my lawn mower blade

This is a bit of a tricky question, since lawn mower blades come in a variety of sizes and thicknesses, and different yards could contain more or less obstacles for a blade to be nicked or dented on, which could then require more frequent sharpening. According to official specifications, you can sharpen your blade and as many times as you need, until more than a third of the blade’s original width is gone.

After this point, you need to throw it away. It’s a good idea to take a measurement each time you sharpen your blade, so you know when to replace them without having to rely on guesswork or your own memory, which, if your memory is anything like my own, is probably less than optimal.

How much does it cost to sharpen lawn mower blades

Once again, a bit of a tricky question. There’s a wide range of tools out there, but luckily, the price range is flexible enough that you can purchase a tool regardless of your budget. If you’re looking for the cheapest options, you could pick up a sharpening file for about $10 depending on where you look.

There are also whetstone attachments that you can purchase for your power drill for about the same price, although multipacks featuring replacement whetstones, blade balancers and gloves can cost somewhere around $15-$20. However, if you have some money saved up, you could invest in a bench grinder. These can go for as cheap as $40 and as expensive as $2000, but some of the highest reviewed grinders out there usually cost around $130-$330.

In addition to buying your sharpening tools, if you haven’t already, it would be wise to purchase other essential tools for blade sharpening. You need a vise clamp to hold the mower blade still while you sharpen it, and depending on the length of the vise, it should cost around $20-$90. You should also pick up a lawn mower blade balancer, so you don’t accidentally throw off the balance of your mower and damage it. Some of the fancier balancers such as the Oregon 42-047 are a little over $100 if you have deep pockets, but the simpler models like the Oregon 42-100 are somewhere around $10, and some $15 whetstone multipacks come included with a balancer.

Lastly, while not essential, I recommend picking up the Arnold Blade Removal Tool while you’re at it. The Blade Removal Tool was specifically made to hold the blade in place while you work on loosening the nut with your combination wrench, and it can definitely save you some hassle.

What is the best lawn mower blade sharpener

There are plenty of gadgets out there that market themselves as the perfect blade sharpening tool. Two of the highest rated blade sharpening tools of 2020 are the Magna-Matic MAG-9000 and the Oregon 88-023. However, these also cost a pretty penny, the MAG-9000 costing a whopping $750 and the 88-023 coming in at about $430. The Wykles personally recommend a bench grinder for the job; not only are they the most efficient way of keeping your blades sharp, they also cost much less. I’ve provided a cheat sheet for some of the best reviewed of these grinders and their average prices below.

JET 577102 – 8-inch, 1 HP, Model # JBG-8A ~ ($330.00)

RIKON Variable Speed Bench Grinder- 8-inch, ¾ HP, Model # 80-800VS ~ ($200.00)

DEWALT DW758 – 8-inch, ¾ HP, Model # DW758 ~ ($130.00)

Central Machinery Bench Grinder- 8-inch, ¾ HP. ~ ($50.00)

WEN 4276 Bench Grinder- 6-inch, 2.1 Amps ~ ($50.00)


It can be intimidating to tackle DIY lawncare for the first time, and just like any other long-term task, it has a lot of steps to follow. However, trying to tackle all those steps at once will overwhelm you. Becoming fluent with just one step at a time will help you not only remember everything better, but also become a skilled and natural homeowner. Just remember to stay sharp!

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