Salman Khan, a former hedge fund analyst, started tutoring his cousin by phone in 2004 when she was 12 years old and struggling in math.

Soon other relatives wanted his long-distance help. Khan began making short, lively videos to walk them through whatever concept was stumping them. He put them on YouTube, and before long, people who weren’t family members started tuning in to the minilessons.

Today, Khan Academy, a free educational website, attracts 19 million learners a month from Maine to Mongolia, including Hawaii. Based in Mountain View, Calif., the nonprofit has users in nearly every country in the world, accessing videos and curriculum in 40 languages. It was built with the help of 14,000 volunteers and is philanthropically funded, fueled by donations.

“It’s all not for profit, no one owns Khan Academy and it’s all for free,” the founder and CEO told local educators in a keynote speech at the recent Schools of the Future Conference at the Hawai‘i Convention Center. “It’s completely noncommercial. … Our mission is to cover all the core subjects, from pre-K all the way to college.”

The lessons at Khan Academy allow learners to work at their own pace with no stigma, he said. In classrooms, students might not master every skill on time, but teachers usually have to move instruction forward on a set schedule, leaving some kids with gaps in understanding.

“Those gaps accumulate,” Khan said, particularly in math. “A lot of kids hit a wall in algebra class. It’s not because they are not bright; it’s because of those little gaps.”

His cousin, for example, had convinced herself she was no good at math, but after a bit of targeted long-distance help, she moved from a remedial class to an advanced one in her New Orleans school.

In the early days, messages from grateful strangers who stumbled upon his videos gave Khan motivation to keep going with the project.

“I had a mother say both her sons had a learning disability, and because of this content they were able to keep up with their class,” he said. “She told me she and her family were praying for me every night.”

He decided to quit his day job to found Khan Academy in 2008, relying on his wife’s income. “Remember,” he said by way of explanation, “I was an analyst in a hedge fund — I was not used to people praying for me.”

More than 2,100 educators from across the state attended the Schools of the Future Conference, Oct. 3-4, which featured numerous speakers and about 150 breakout sessions. It was sponsored by the Hawaii Association of Independent Schools, Department of Education, Pillars of Peace Hawaii and Hawaii Society for Technology in Education.

Some attendees had heard of Khan Academy and used it with their students, while others were discovering it for the first time.

“There were points during his talk that I cried,” said Tracy Jones, a sixth grade teacher at August Ahrens School in Waipahu.“The kids were so excited about their learning. I had heard of Khan but never really explored it. At the first break I just jumped on there and signed up.”

Her colleague Janelle Bailey, who teaches first grade, agreed: “I was definitely inspired by his speech, and to see the different types of children that’s he’s reaching across the world is amazing.”

Children such as a girl from halfway across the world who posted a cheery video message that Khan showed conferees. “I am Zaya from Mongolia,” she said. “Your videos are so interesting and funny. Make more lessons.”

Khan said he assumed she was upper middle class since her English was quite good and she had internet access. But he found out otherwise.

“It turns out there was a group of volunteers from Cisco Systems who were using their vacation time to go to Mongolia and set up computer labs with internet in orphanages,” Khan said. “Zaya was one of those orphans.”

“What’s been even more incredible since then is that Zaya has graduated from high school and she’s become the top contributor to Khan Academy in the Mongolian language,” he said.

Khan Academy’s ultimate goal is to offer a “free, world-class education to anyone anywhere,” but rather than replacing teachers, it offers tools for students as well as educators, according to its founder.

“If students can get micro-tutorials in their own time and pace, it frees up the classroom to go deeper, for Socratic dialogue, to do peer-to-peer instruction,” he said.

Vice Principal William Olk of Central Middle School in downtown Honolulu said his school uses Khan Academy in algebra classes and for small-group instruction. Central’s principal, Anne Marie Murphy, asked Khan to consider adding some content in Chuukese.

“The majority of our children at our school are Micronesian and speak Chuukese,” Olk said. “He had not even heard of it, so he’s going to look into it, which is exciting.”

Today, major donors to Khan Academy include the Bill and Melinda Gates Foundation, Google, Bank of America, College Board and the Omidyar Fund. When Bill Gates’ representative first reached out to him, Khan recalls, “they were surprised that I was one guy operating out of my house.”

Today the Khan Academy team spans the globe.

“I get disproportionate credit for it,” Khan said. “We have over 200 full-time folks in our offices, a lot of current and ex-teachers, engineers, designers helping make this happen. We’ve had tens of thousands of teachers … helping us implement this, learning what works, what doesn’t work. There’s hundreds of thousands of people who’ve donated.”

One of his favorite success stories is a girl from Afghanistan named Sultana. When the Taliban took over her village, she was forbidden from going to school. Her brother gave her a computer with internet access, and she began learning English, then moved on to math and physics with help from Khan Academy.

She decided she wanted to become a physics researcher in the United States, and an online friend in Iowa advised her to take the SAT and try for a scholarship. But the exam isn’t offered in Afghanistan.

“She lies to her parents and smuggles herself across the border from Afghanistan to Pakistan, one of the most dangerous borders in the world, a 30-hour journey, just to take the SAT,” Khan recounted. “She does shockingly well for someone who frankly never had any formal schooling.”

New York Times columnist Nicholas Kristof spotlighted her case in a 2016 column that helped Sultana gain political asylum in the United States. She is now studying quantum computing but keeps a low profile because she fears for the safety of her family back home, Khan said.

“So if any of you have 16-year-olds who are complaining about having to get up on a Saturday morning,” he told teachers at the conference, “tell them this story.”