Not only are college courses going online, but so is tutoring help.

And, as a Wall Street Journal article reports, this innovation is a very good development for struggling scholars.

It’s a nightly dilemma in many households: A student hits a wall doing homework, and parents are too tired, too busy—or too mystified—to help.

Ordering up a tutor is becoming as easy for kids as grabbing a late-night snack. Amid rapid growth in companies offering online, on-demand tutoring, students can use a credit card to connect, sometimes in less than a minute, with a live tutor. Such 24/7, no-appointment-needed services can be especially helpful to students with tight budgets or tight time frames or those in remote areas.

“All of a sudden, the world opens up to them,” says Michael Horn, executive director of education for the Clayton Christensen Institute, a San Mateo, Calif., education and health-care think tank.

That said, the quality of on-demand scholastic support can be uneven, and the catch-as-catch-can approach to enlisting a tutor may not be best for struggling students who need sustained help. Sessions can bog down on technical glitches, and language barriers can cause problems on sites that rely on tutors from abroad.

Prices, ranging from about $24 to $45 an hour (and often prorated to the minute), are cheaper than what many skilled tutors charge in a student’s home. And parents and students say the quick homework fix can ease stress and make evenings at home more peaceful.

Whenever Peggy Bennett of Dallas tried to help her 13-year-old daughter, Chloe Friedman, with her eighth-grade physics and algebra homework, “we’d always end up bickering,” Ms. Bennett says, with Chloe often objecting that the teacher did it differently. “It was a lose-lose situation.”

Chloe says she was skeptical when her mom helped her sign up last month on Tutor.com, a New York City-based provider of on-demand tutoring. But after she logged on one evening for algebra help, a tutor, identified only by a first name and last initial, responded within a minute. Chloe says she was guided to figure out the answers, using text chat and an interactive “whiteboard” that displayed their writing and calculations on a shared screen. After hearing nothing but typing for about 10 minutes, Ms. Bennett says she heard Chloe yell from the other room, “They told me I did a good job!” Ms. Bennett adds, “That was all that she needed.”

Chloe, who takes classes in dance, acting and singing, also uses Tutor.com on her smartphone at the dance studio between classes. She says she recently got help solving a math problem in less than 10 minutes.