How much annual GDP growth would China need to catch up with US GDP by 2030?
[A Thread]
(I'll put the exact calculations in a response post below)

Here are the numbers:
Currently 5 year growth forecasts for the US give an expected average growth of about 2% a year [1][2]. However, to give a better idea of possible scenarios, I will also run the numbers on a much more pessimistic hypothetical of only 1% annual GDP growth until 2030 and a reference case of 0% growth. Here is the result:

To reach US GDP if for the 2% growth scenario, by 2030 China would need to grow by 8.47% annually. 

(1/3)

Here is the growth forecast for China:

Source: Statistica 2024 [3]

This seems quite pessimistic, but Reuters does agree with the projection and adds that "The IMF said it had revised up both its 2024 and 2025 GDP targets by 0.4 percentage points but warned that growth in China would slow to 3.3% by 2029 due to an ageing population and slower expansion in productivity." [4]

If this is accurate, China would not even catch up to the 2023 US GDP by 2030.

(2/3)

Here is a graph on how different cases where China's GDP catches up to the US would look like, as well as China's GDP growth if it follows the forecast cited above, which is also consistent with the IMF and Reuters forecasts:

(3/3)

Sources:

US growth forecast (the first two items I've got when googleing "us growth forecast 5 years"):
[1] https://www2.deloitte.com/xe/en/insights/economy/us-economic-forecast/united-states-outlook-analysis.html
[2] https://www2.deloitte.com/xe/en/insights/economy/us-economic-forecast/united-states-outlook-analysis.html

China growth forecast:
[3] https://www2.deloitte.com/xe/en/insights/economy/us-economic-forecast/united-states-outlook-analysis.html

[4] https://www.reuters.com/world/china/imf-upgrades-chinas-2024-2025-gdp-growth-forecasts-after-strong-q1-2024-05-29/#:~:text=The%20IMF%20said%20it%20had,slow%20to%204.5%25%20in%202025.

Calculations:

1. Initial GDP in 2023:

• U.S.: $27.36 trillion

• China: $17.79 trillion

2. Formulas Used

Future Value Formula (for us GDP in 2030):

Future Value = Present Value × (1 + Growth Rate)^Number of Years

Compound Annual Growth Rate (CAGR) Formula (for calculating required growth for China):

CAGR = ((Future Value / Present Value)^(1 / Number of Years)) - 1

3. Calculations

US GDP Calculations:

• 0% Growth: $27.36 trillion (Constant)

• 1% Growth: $27.36 trillion × (1 + 0.01)^7 ≈ $29.33 trillion

• 2% Growth: $27.36 trillion × (1 + 0.02)^7 ≈ $31.43 trillion

Required CAGR for China to Match US GDP by 2030:

• To match US at 0% Growth: ((27.36 / 17.79)^(1/7)) - 1 ≈ 6.34%

• To match US at 1% Growth: ((29.33 / 17.79)^(1/7)) - 1 ≈ 7.41%

• To match US at 2% Growth: ((31.43 / 17.79)^(1/7)) - 1 ≈ 8.47%

I've just noticed that I've calculated to the end of 2030 and the market says "before 2030" so it should be even more unlikely, but oh well.

Here is a similar question in metaculus. Notice that metaculus forecasters give a 60% probability that China's GDP will surpass US GDP by 2050.

Also take a look at the numeric market for when China's GDP will surpass that of the US:

china keeps kneecapping its own industries (video games, afterschool tutoring, electric scooters). if they just deregulated and stopped trying to do communism they’d beat the US for sure.

As it stands, it all depends on whether Xi will be able to make good top down decisions. maybe their big solar play will work out idk

What happens in 2050 if it looks like China is unlikely to pass the US?

@JoshuaWilkes Would still resolve "after 2049". I appended "or never" to make that more clear.

You got me thinking about some cases like "China doesn't exist anymore" or "US doesn't exist anymore". However, sometimes states disappear only temporarily.