In May, the Institute for the Quality of Life released its 2025 Happy City Index.

The 200 cities in the report were separated into three groups: gold, silver, and bronze, with gold meaning those cities scored the highest across all metrics combined.

To rank the world's happiest cities, researchers tracked 82 indicators of happiness across six major categories:

1. Citizens
2. Governance
3. Environment
4. Economy
5. Health
6. Mobility

2025 is the first year the index included health as a category. It's something that Dr. Bartosz Bartoszewicz, Director and Co-creator of the Index, tells CNBC Make It was an important addition because of the covid-19 pandemic.

"We've added health, and we didn't know what the results were going to be, and what was surprising is that most of the cities that were gold cities in the past remain," Dr. Bartoszewicz says. "It shows they are still developing in a sustainable way and that is great because it's not only about mobility or governance. It's about the whole structure of the city."

The United States didn't have any cities rank in the top 10, but did have two get the "gold city" distinction: New York City at No. 17 and Minneapolis at No. 30.

18 U.S. cities were ranked and make up almost 10% off the entire index, which Dr. Bartoszewicz is still a good result.

Copenhagen is the happiest city in the world

Copenhagen, Denmark, ranked No. 1 on the Happy City Index with a total score of 1,039.

"What is amazing about Copenhagen? First of all, its ability to be open for innovation. Its educational system is of very good quality and it's affordable," Dr. Bartoszewicz says.

Dr. Bartoszewicz adds that despite Copenhagen being ranked No. 1, it still has its issues, like housing. Apartment prices have doubled in the past 10 years, according to Boligsidens Markedsindeks, a Danish housing market portal.

"Every city has its challenges but Copenhagen does a good job of not only confirming they have a problem but they are even listing them and telling people to join them in coming up with how to solve these problems," Dr. Bartoszewicz says. "Living in Copenhagen is still a challenge so even though it's first, they still have a lot of problems to solve."

Denmark frequently ranks as one of the happiest countries in the world, so it's no surprise that its capital city took the top spot on this list.

In 2024, the country the No. 2 happiest in the world, according to the World Happiness Report.

Denmark is also the No. 1 country where expats are most satisfied with their jobs, career opportunities, and work-life balance, according to a 2024 Expat Insider survey from InterNations, the online global community for people who've moved abroad.

In Denmark, residents pay some of the world's highest taxes— up to half of their income — it is balanced out by the fact that most healthcare in the country is free, childcare is subsidized, university students pay no tuition and receive grants to help cover expenses while studying.

The 10 happiest cities in the world

1. Copenhagen, Denmark
2. Zurich, Switzerland
3. Singapore, Singapore
4. Aarhus, Denmark
5. Antwerp, Belgium
6. Seoul, South Korea
7. Stockholm, Sweden
8. Taipei, Taiwan
9. Munich, Germany
10. Rotterdam, Netherlands

For the second year in a row, Switzerland's largest city, Zurich, ranked No. 2 in the index with a score of 993.

The city is a global financial hub that is renowned for its economic strength and high quality of life, according to the report. It scored highly in the categories of citizens and governance.

"In Zurich, people have access to the best quality of education and a really strong economy. If you live in Zurich, your average income is much higher than the rest of the country. You're earning almost double what other cities in Switzerland do," Dr. Bartoszewicz says.

Zurich is divided into 12 districts and was named the world's smartest city in 2024 for its innovative integration of new technologies. The Economist Intelligence Unit ranked it the third most liveable city in 2024.

The city is often referred to as the "City of Banks" due to its global financial reputation. It is also one of the most expensive places to live in the world.

Want to boost your confidence, income and career success? Take one (or more!) of Smarter by CNBC Make It's expert-led online courses, which aim to teach you the critical skills you need to succeed that you didn't learn in school. Topics include earning passive income online, mastering communication and public speaking skills, acing your job interview, and practical strategies to grow your wealth. Use coupon code MEMORIAL to purchase any course at a discount of 30% off the regular course price (plus tax). Offer valid from 12:00 am Eastern Time ("ET") on May 19, 2025, through 11:59 pm ET on June 2, 2025. Terms and restrictions apply.

Plus, sign up for CNBC Make It's newsletter to get tips and tricks for success at work, with money and in life, and request to join our exclusive community on LinkedIn to connect with experts and peers.