There are many readability tools that instructors can use to help adult learners select reading materials. We describe and compare different types of readability tools: formulas calculated by hand, tools found on the Web, tools embedded in a word processing program, and readability tools found in a commercial software program. Practitioners do not need expensive software or extensive training to determine reading levels of materials. We include instructions for using the Flesch Reading Ease, Flesch-Kincaid, SMOG, Dale-Chall, Spache, FORCAST, Fry, and RIX readability formulas. (Contains 4 tables.)