To ensure that every child can learn the skills required to work in New York City’s fast-growing technology sector, Mayor Bill de Blasio will announce on Wednesday that within 10 years all of the city’s public schools will be required to offer computer science to all students.

Meeting that goal will present major challenges, mostly in training enough teachers. There is no state teacher certification in computer science, and no pipeline of computer science teachers coming out of college. Fewer than 10 percent of city schools currently offer any form of computer science education, and only 1 percent of students receive it, according to estimates by the city’s Department of Education.

Computer science will not become a graduation requirement, and middle and high schools may choose to offer it only as an elective.

But the goal is for all students, even those in elementary school and those in the poorest neighborhoods, to have some exposure to computer science, whether building robots or learning to use basic programming languages like Scratch, which was devised by the Massachusetts Institute of Technology to teach young children the rudiments of coding.

At least two other American cities have recently made commitments to offering computer science to all their students. Chicago has gone the furthest, pledging to make a yearlong computer science course a high school graduation requirement by 2018, and to offer computer science to at least a quarter of elementary school children by then. The San Francisco Board of Education voted in June to offer it from prekindergarten through high school, and to make it mandatory through eighth grade.

Technology companies, which have been criticized for having very few female and minority employees, have supported these efforts, partly to expand and diversify the pool of qualified job applicants. Google and Microsoft have contributed to Chicago’s initiative, and San Francisco has received financing from Salesforce, Facebook and Zynga.

Noting that tech jobs in New York City grew 57 percent from 2007 to 2014, Gabrielle Fialkoff, the director of the city’s Office of Strategic Partnerships, said, “I think there is acknowledgment that we need our students better prepared for these jobs and to address equity and diversity within the sector, as well.”

New York City plans to spend $81 million over 10 years, half of which it hopes to raise from private sources. Some of the early contributions have come from the AOL Charitable Foundation, the Robin Hood Foundation and the venture capitalist Fred Wilson and his wife, Joanne, who previously financed New York City’s first high school devoted to computer science, the Academy for Software Engineering.

The city estimates that it will have to train close to 5,000 teachers to meet its pledge to provide the instruction at every level of schooling. Some might teach computer science exclusively, while others might be traditional elementary school teachers who will learn to incorporate it into the curriculum.

Schools that have begun to incorporate computer science say the biggest challenges have been finding people qualified to teach it, and adding yet another requirement to the mountain of skills that students already need to graduate. The National Science Foundation has said it plans to train 10,000 teachers to teach computer science.

“The difficulty is getting enough teachers who are trained in it, and trained well enough to make it a good introduction to computer science,” said Barbara Ericson, the director of computing outreach at Georgia Tech’s College of Computing. “And if you are well-trained in computer science, you can make a lot more money in industry than teaching.”

Nationally, computer science jobs are some of the fastest growing and highest paying, but a majority of students have no access to computer science classes before college. A quarter of principals say their schools offer computer programming courses, according to data from Google and Gallup. Just 6 percent of high schools are certified to offer Advanced Placement computer science courses.

But interest in computer science is growing among both schools and students. Last year, the number of students taking the A.P. test increased 25 percent over the year before, to 48,994.

In New York City, some of the most elite public schools, like Stuyvesant High School, have offered computer science courses for years. Mr. Wilson said in an interview that he had long wanted to see computer science education expanded to a wide range of schools. But he said it was only in the past several years that the city had evidence, from the Academy for Software Engineering and other programs, that students who were behind grade level in math and reading, as most students in the system are, could benefit from computer science classes.

The Laboratory School of Finance and Technology, a middle and high school in the Bronx, requires all its students to take computer science courses in each year of middle school.

One of the school’s computer science teachers, Ben Samuels-Kalow, is certified to teach in social studies, but when he was doing his teaching residency at the school in the 2012-13 school year, the principal, Ramon Gonzalez, noticed that he was computer savvy and asked if he would participate in a pilot program aimed at training teachers in teaching computer science.

Mr. Samuels-Kalow said he found that students are often willing to work harder in his classes than in their other classes, because the rewards of, say, being able to play a game that they designed were so enticing. And, by working with his colleagues, he said, he can sometimes find ways to reinforce concepts that students are struggling with in other courses.

“I’ve literally had a conversation with a student where she’s saying, ‘I really don’t like math,’ as she’s walking me through a JavaScript function to have an interactive photo gallery on a web page that she had also built from scratch,” Mr. Samuels-Kalow said. “I looked at her and said, ‘This is harder math than what you’re doing in your math class.’ ”

In New York City, as in the rest of the country, the students who elect to take computer science courses tend to be male and either white or Asian. Of the 738 city students who took the Advanced Placement examination in computer science in 2014, only 19 percent were black or Latino and only 29 percent were female, according to the Education Department. (The fractions are even lower nationally.)

City officials and Mr. Wilson, the venture capitalist, hope that exposing all students to computer science concepts in elementary school will increase those numbers.

“If we can get them earlier, I think we can get them excited about it,” Mr. Wilson said.