Measuring your lawnmower blade

Getting the length of your blade

When you are replacing your lawnmower blade, the simple, and easiest solution, is to replace the blade based on the part number in your owner’s manual. But, what about when you don’t have the owner’s manual? Well, then you need to measure your lawnmower blade. And it’s really easy to measure your blade incorrectly, which can lead you buying the wrong blade, and ending up needing to return what you bought, and try again.

When you are measuring your lawnmower blade, think of it like measuring your Television. You are going NOT going to measure it like this:

When you measure a blade like this, it takes out several critical elements related to the blade. The most important among them, it doesn’t account for the width of the blade. So, when you measure a lawnmower blade, you want to make sure that you are measuring it, diagonally, from cutting tip to cutting tip, like so.

Center Hole

So, now you know what the length of your blade is. So, what about the Holes in the blade? Those measurements can vary wildly as well, even within the same brand of lawnmower. For a blade with Just a Center Hole, you simply need the diameter of the Center Hole.

This is the most important hole in the blade. Even if you don’t get the measurements of the outer holes, this is the most important. With the length, and this, you can get pretty close to finding the blade you need.

But, the Center hole of my blade isn’t round!

Yes, sometimes, lawnmower manufacturers decided that they wanted to use a Star, or a Rectangle, or an Rounded Rectangle. In those cases, you need to know how many points the star is (4, 5, 6, or 7 generally),  or, the measurements of the rectangle (Length and Width)

Outer Hole

Some blades have a series of outer holes. These can be used with blade adapters, and other bolt on attachments to the blade. If your blade has outer holes, it’s a good idea to have two measurements associated with the outer holes. The Diameter (just like the center hole), and the Center to Center distance. This distance, is found by measuring from the center of one outer hole, across the blade, to the center of the opposing outer hole, like so.

With these measurements (Length, Center Hole, Outer Hole Diameter, and Outer Hole Center to Center), You will have the best chance at making sure you purchase the correct blades for your mower. And if you have questions, we are here, ready to help make sure you get the right part for the job.