Abilene, I'm sure there is a chart somewhere online, but I don't have a link. Can you ask the person who administered the test to give you the full report? There is a standard report that is generated with the WJ-III which will give standard scores, percentiles, grade equivalents and a ton of other info for each subtest.
FWIW, I haven't found having the grade equivalents for this type of achievement test to be terribly useful. They are grade equivalents for a very limited set of specific skills. If you're looking for grade equivalents to advocate for acceleration, having an out-of-level achievement test or a test or work samples showing mastery of skills directly tied to your school district's grade level curriculum benchmarks.
polarbear