How to Find the Right Replacement Mower Blade

A mower blade that is even slightly wrong can vibrate, cut poorly or not mount at all. The good news: finding the right one takes about five minutes if you check a few things in the right order.

1. Start with the OEM part number

The most reliable way to match a blade is the original equipment manufacturer (OEM) part number. You'll usually find it in one of three places:

• Stamped on the blade itself, often near the center hole. Clean off the grass and rust to read it.
• In your owner's manual, in the parts list for the mower deck.
• On the manufacturer's parts lookup, using your mower's model and serial number (on a sticker on the frame or under the seat).

Once you have the OEM number (for example John Deere M143520 or Hustler 784256), search for it on our site. Our blade listings show which OEM numbers each blade replaces.

2. If you can't find the number, measure

Take the old blade off (see the safety note below) and measure these:

• Length: measure diagonally from one cutting corner to the opposite corner, not straight across the middle. This is how blade makers list length.
• Center hole: note the size and shape. It may be round, a star (5, 6 or 7 points), or a bow-tie. The shape has to match your spindle or blade adapter.
• Width and thickness: measure near the center of the blade.
• Offset: lay the blade on a flat table. If the center sits above the table when the cutting edges touch, that height is the offset.

With length and center hole you can narrow the choice down quickly; width, thickness and offset confirm the match.

3. Check your deck size and blade count

Most riding mowers and zero-turns use two or three blades. A 42" deck usually takes two, while 48" to 72" decks usually take three. Always replace all the blades on a deck at the same time so the cut stays even.

4. Pick the lift style

The same size blade often comes in several styles: standard lift, high lift, mulching and Gator. Read our guide to high-lift vs. mulching vs. Gator blades to choose the one that suits how you mow.

Safety first

• Turn the engine off, remove the key and disconnect the spark plug wire before touching the blades.
• Wear heavy gloves. Blades are sharp even when worn.
• Block the blade with a piece of wood before loosening the bolt.
• Tighten the new blade to the torque listed in your owner's manual.

Ready to shop? Browse our lawn mower blades by brand, or check our blade adaptors if your spindle hardware is worn too.