Replacing Your Lawn Mower’s Blade Can Keep Your Grass Looking Crisp: Here’s How to Do It in 7 Easy Steps (2025)

Replacing your lawn mower blade every year or two is essential to keeping your grass looking sharp. Over time, the blade’s edge will dull, either from general wear or damage from debris like sticks, stones, and roots. You can extend its life by sharpening it at the start of growing season, but eventually, you will need to replace it when the blade becomes too nicked and worn. Luckily, this is an easy chore that you can easily perform yourself with just a few tools.

Keeping your lawn mower blade sharp is important. The very act of mowing is traumatic for your grass, but a cleaner cut ensures that it recovers quickly. Mowing with a dull, rough blade can leave ragged tips on cut grass, which could lead to disease, fungi, and browning.

Prepping your lawn mower blade, either sharpening it or swapping in a new one, should be a part of your spring lawn season prep. If you aren’t sharpening your lawn mower blade, it’s a good idea to change it every season. Even if you do sharpen it, though, you should still replace the blade every two years. With a few simple tools and a bit of gumption, you can easily do it yourself, saving time and money.

The Expert: My experience with lawn mowers dates back to my school days working a summer job as a landscaper, where general maintenance on all of our power tools was part of our daily routine. I’m now a Reviews Editor for Popular Mechanics, covering lawn mowers and other DIY topics, which I also previously worked on at U.S. News & World Reports. I also checked in with our resident mower Test Editor, Bradley Ford, for his input and expertise.

Before you go out and buy a replacement lawn mower blade, make sure you know what you’re looking for. Note the size and style number of your lawn mower (the model number of the mower is in the manual or visible on the deck of the mower), and the type of cutting you prefer (general purpose, mulching, etc). The original manufacturer will recommend that you buy its blades, but there are high-quality, compatible aftermarket blades. Just check that the blades are compatible with the model number of your mower (you can find this out on their websites).

Push mowers typically require one blade, though more advanced versions may use two. Riding and zero-turn mowers may use up to three. It’s much wiser to replace all the blades at once to ensure consistent cutting. Pairing a new blade with one you’ve been using for a while will produce uneven cuts that could make your lawn look ragged.

Replacement lawn mower blades are not terribly expensive. A single blade to fix up a push mower can run you anywhere from $15 to $25. A pack of two or three to maintain a riding mower should cost between $30 to $60. (Of course, there are always high-end parts that can cost even more.) However, paying a local store or repair shop to change it for you can get costly, starting around $50, and is not readily available at large retailers like Home Depot or Lowe’s.

To make this guide comprehensive, I’ve written out two sets of instructions: one for push mowers and another for riding mowers. Replacing a riding mower blade (or set of blades) is a bit more complicated, but both are very doable.

• A socket wrench
• A block of wood or 4 x 4 (or a C-clamp)
• Lubricant (such as WD-40 Penetrant)
• A putty knife
• A mower jack (for riding mowers)

1 Prep your mower for safety. To keep the motor from accidentally starting, disconnect it from its power source. For gas mowers, remove the ignition wire from the spark plug, then drain the gasoline from the tank to avoid spilling when you tip the mower over. For electric mowers, remove the batteries.

Tip: If you want to leave the fuel in your gas mower, try this hack: Undo the gas cap, then place a sandwich bag over the hole and the screw threads, and screw the cap back on. This will create a seal, preventing fuel from leaking out of the top.

2 Tilt the mower onto its side to expose the blade. Most mower blades are attached by one or two bolts. Identify and spray them with lubricant, then wait for 10 to 15 minutes. While the lubricant is working its magic, note the orientation of the blade, and mark the down-facing side with a small piece of blue painter’s tape or a marker to remind you which side faces the ground when you reattach it and the mower is upright. If you lose track of the blade’s orientation, keep in mind that the beveled edge of the blade should always be on top.

3 Place the wood inside the bottom of the mowing deck and up against the blade at a 90-degree angle. This will keep the blade from turning as you loosen the bolts. (Wedging the wood at a non-perpendicular angle could damage a hard-to-loosen blade.)

Alternatively, you can use a C-clamp as a stopper. Simply, attach to the lip of the deck so that the end of the clamp stops the blade from spinning. I recommend putting a piece of wood between the exterior of the deck and the clamp head so it doesn’t scratch the mower’s paint job as you tighten it.

4 Remove the bolt(s) with your socket wrench and pull off the blade. If you need to hold the blade while loosening it, wear cut-resistant gloves.

5 If needed, clean the deck. Remove any caked-on grass with your putty knife or another tool with a wide, flat edge. I don’t advise thinner, pointier tools for this job, such as a screwdriver (which I’ve seen people use). Not only does it add time, but it could also scratch or damage the underside of the deck.

6 Fasten the new blade in its place. When you start screwing in the bolt, do it by hand for a few turns before switching to the socket wrench. This will help you avoid cross-threading the bolt, which could damage the threading or lead to a misaligned blade.

7 Finally, remove the wood block or C-clamp, tilt the mower back upright, reattach your spark plugs or reinstall your batteries, and you’re ready to mow.

Changing the blades on a riding or zero-turn mower takes a bit longer than maintaining a push-mower, but it’s not as hard as it looks. Many mower manufacturers advise removing the cutting deck, where the blades are housed. It’s a time-consuming process that differs for each model and make. To avoid this, I recommend lifting the mower with a mower jack so you can swap out the individual blade or blades. It requires an extra tool, but makes the process far easier in the end.

Mower jacks come in a variety of designs but usually raise a riding mower near the front or rear wheels. Some are designed to lift the whole mower up at either side. For changing blades specifically, look for a jack that lifts the mower from the front two wheels, if possible: It allows you to complete the full swap with just one lift.

Whatever jack you pick, confirm that it’s designed to handle the total weight of your specific mower. You don’t want to be working under a 600-pound mower with a jack without feeling confident that it can carry that weight.

Caution: Using a jack designed for cars and jack stands can be dangerous. (Sadly, I’ve seen more than my fair share of amateur YouTube tutorials recommend this.) If you set up your jack under the mowing deck or another part of the chassis that isn’t meant to bear the mower’s full weight, you could damage the mower or, worse, hurt yourself.

1 Park the mower on a level area, set the parking brake, and raise the cutting deck to the highest setting so you have as much room to work with as possible. For added safety, set a wheel stop or bricks behind the rear wheels to prevent accidental rolling.

2 Take steps to prevent the motor from turning on accidentally. For gas mowers, disconnect the spark plugs. For electric mowers, remove the batteries (if possible) and disconnect the power cables that connect the mower to the cutting deck. Keep in mind: Depending on the number of blades, there may be multiple cables.

3 Set up your mower jack: Follow the operating instructions, which will tell where exactly how where to place the wheels, and safely raise the mower to a level that gives you enough room to get under the cutting deck for blade removal and replacement.

4 Spray the bolt(s) for each blade with lubricant and wait 10 to 15 minutes. While you wait, mark the orientation of the blade on the down-facing side with a small piece of blue painter’s tape or a marker, same as you would with a push mower. Also, note the order of any washers that sit between the bolt and the blade.

5 To keep the blade from spinning as you remove it, attach a C-clamp to the deck so the end of the clamp blocks the blade from extending. Place a piece of wood between the outer side of the deck and the clamp head, so the metal of the clamp doesn’t scratch the paint as you tighten it. You’ll need to repeat this step for each blade as you go, or set multiple C-clamps.

If there is a center blade that you cannot hold and block with a C-clamp, hold the blade in place with a gloved hand as you remove the bolt. Do not attempt this without cut-resistant gloves.

6 Remove the bolt(s) with your socket wrench and remove the blade. If you need to hold the blade while loosening it, make sure to wear cut-resistant gloves to keep your hands safe. Repeat this step for each blade.

7 If needed, clean the deck. Remove any caked-on grass with your putty knife or another tool with a wide, flat edge.

8 Install the new blades and secure them by tightening the bolts. Start by screwing in each bolt by hand for a few turns before switching to the socket wrench. This will help you avoid cross-threading the bolt.

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