With a surface area of more than nine million square kilometers each, the United States and China rank among the world's four biggest countries, after Russia and Canada.

China, the world's second-most populous country after India with 1.4 billion inhabitants, has four times more people than the United States.

- Economic powers - 

The United States is the world's biggest economy, with a gross domestic product of more than US$29 trillion in 2024, followed by China with more than $18 trillion, according to the International Monetary Fund.

China was in 2024 the world's biggest exporter of goods, totaling $3.6 trillion and the United States the biggest importer at $3.4 trillion, according to the World Trade Organization.

The United States has a big trade deficit with China when it comes to goods, reaching $355 billion in 2024, according to the United Nations Conference on Trade and Development.

Since returning to the White House, President Donald Trump has slapped 145 percent tariffs on many Chinese imports. 

Beijing has retaliated with levies on US goods of 125 percent.

- Biggest polluters -

China is the world's biggest emitter of greenhouse gases, followed by the United States.

The United States had committed itself to slashing its emissions by half by 2030, compared with 2005 levels, but Trump, openly skeptical about climate change, has announced a new withdrawal of his country from the Paris climate accord.

China committed itself to stabilizing its CO2 emissions by 2030 and then to achieve carbon neutrality by 2060.

- Digital giants -

The United States is home to the "GAFAM" group of tech titans: Google, Apple, Facebook owner Meta, Amazon and Microsoft.

China has its own tech giants, "BATX": search engine Baidu, e-commerce platform Alibaba, video game and social media firm Tencent and smartphone maker Xiaomi.

The rise of artificial intelligence has opened a new front in Sino-American tech rivalry.

Since the launch of ChatGPT in November 2022, AI generative models have mushroomed in the United States and China.

The Chinese start-up DeepSeek, founded in 2023 by the High-Flyer investment fund, shook up the AI world in January with its R1 chatbot, able to match the functions of its Western competitors at a fraction of the cost.

The two sides have also clashed over TikTok.

The hugely popular video-sharing app, which has more than 170 million American users, is under threat from a US law passed last year that orders TikTok to split from its Chinese owner ByteDance or get shut down in the United States.

The ban took effect in January but Trump has delayed it until June 19 to give time to find a buyer for TikTok.

The ban is motivated by national security fears and belief in Washington that TikTok is controlled by the Chinese government

- Military powers -

The United States is the world's biggest spender on defense. 

It earmarked $916 billion in 2023, three times more than China, which ranked second with $296 billion, according to the Stockholm International Peace Research Institute.

The United States and Russia have nearly 90 percent of the world's nuclear arsenal, with more than 5,000 nuclear warheads each at the start of 2024, including those withdrawn and waiting to be dismantled. 

That is far before China which has 10 times fewer nuclear warheads.

- The space race -

China, which sent its first "taikonaut" into space in 2003, has over the past decades invested billions of dollars in its space programme to catch up with the United States and Russia.

In 2019 its Chang'e-4 made a controlled landing on the far side of the Moon, a world first. In 2021 it landed a small robot on Mars.

It hopes by 2030 to send a manned mission to the Moon, and plans to build a lunar base.

NASA's Artemis space program is planning to return astronauts to the Moon in 2027 and future missions to Mars.

In order to reduce the mission costs, the US space agency has partnered with private companies to send material and technology to the Moon.