§ How-To
How to Measure Your Old Spool to Find a Replacement
Three measurements and one number that guarantee the replacement spool actually fits.
Don’t guess — these four data points get you the right spool every time.
1. The model number
Start with your trimmer’s model number (on the housing label) and the OEM spool/part number molded into the old spool. That alone usually finds the match.
2. Spool diameter
Measure across the spool face with calipers. A few millimeters off and it won’t seat.
3. Center hole & post
Measure the center bore and note any locating tabs or notches — these key the spool to the head.
4. Line diameter
Measure the old line (or read it off the spool). Order the same gauge unless you’re deliberately stepping up.
Cross-reference
Many replacement spools list every compatible model in the title. Search your brand page and match the part number — then check the fitment list on the listing before buying.