How to use the cross-cut adhesion grade converter
After scoring a lattice and lifting the tape, enter the share of the area that peeled away. The page reads the matching six-step class from the International Organization for Standardization ISO 2409 and the rating from ASTM International D3359 side by side. You can also pick a grade and read back the area band it stands for.
The area bands are copied from the published ISO 2409 and ASTM D3359 classifications as of October 2026. The sources consulted were secondary ones, such as coating maker class notes and patent literature, so please check the standards themselves. You may overwrite the band limits with your own values.
A cutter spacing tied to film thickness was not confirmed in an authoritative source, and published descriptions disagree, so no spacing is suggested here; your entry is only kept on record. Tape type and peel angle corrections and film thickness measurement are not covered. Percent and millimeter units are used because the published classification is given that way. The result is for reference and does not replace a test report. A pass or fail call needs review by a qualified tester.
Frequently asked questions
The two classifications number their steps the other way round. ISO 2409 calls 0 the best result because nothing peeled, while ASTM D3359 calls 5B the best. So the same test written as ISO 1 and as ASTM 1B describes completely different coatings.
How the cutter spacing should follow the film thickness was not confirmed in an authoritative source. Published descriptions disagree, so no value is stated here. Whatever spacing you enter is only echoed back as part of the test record.
This converter only maps the percentage you type onto the published area bands. An eyeballed share and an image-counted share can land in different classes, so record the measuring method next to the result in your test report.