The OECD has published the GDP of the metropolitan areas in OECD countries in the year 2019. Here is the list. All metro areas are defined by OECD using the same methodology (central core area + commuter belt with more than 15% of residents in employment commuting to the central core area). Figures are in billion US dollars at market exchange rates (not at PPP).
This is the position of the respective metro area economies in the last year before Covid-19. It won't be possible to produce another snapshot of metro area economies before 3 or 4 years due to the upheavals of Covid, which make data rather meaningless after 2019 and probably until 2023.
For comparison, I'm also adding the Brazilian metro areas (defined by the Brazilian statistical office, whose definition is very similar to OECD's definition of metro areas). I'm also adding Hong Kong, Taipei, Singapore, and the Chinese metro areas. For China, the figures refer to the Chinese municipalities, i.e. large regions that correspond reasonably to the metro areas of the large Chinese cities (in fact the municipalities are slightly larger than the metro areas, as they include rural territories, but these add little to the overall GDP of the municipalities). Only exceptions: Guangzhou, which is aggregated with Foshan in the list, as Guangzhou and Foshan form essentially one city nowadays, and Chongqing, whose municipality is way too large, so here I've given the figures for two smaller statistical territories defined by the Chongqing authorities.
I've also added Moscow. Nobody has ever defined the extent of the Moscow metro area, so I give the GDP of the city of Moscow alone (this is the lower bound), and the GDP of city of Moscow and Moscow oblast combined (this is the upper bound). St Petersburg has a GDP too small to make it in the list.
I've added the population of all areas, to better understand the extent of each territory.
PS: I'm also adding Delhi, even though its GDP is still too low to normally make it in the list. Delhi is the only Indian city for which we have a GDP figure, due to the fact it is a union territory of India (similar to states). There are no data for divisions below state level (unlike China which produces GDP figures for administrative divisions below province level).
GDP of the metro areas in 2019, in billion of US dollars (at market exchange rates):
- New York (19.9 million inh.): 1,902
- Tokyo (36.4 million inh.): 1,695
- Los Angeles (17.8 million inh.): 1,240
- San Francisco-Oakland-San Jose (6.7 million inh.): 940
- Paris (13.1 million inh.): 876
- London (12.4 million inh.): 827
- Seoul (23.6 million inh.): 816
- Washington-Baltimore (9.2 million inh.): 791
- Chicago (9.5 million inh.): 727
- Osaka-Kobe-Kyoto (17.0 million inh.): 640
- Dallas-Fort Worth (7.8 million inh.): 556
- Shanghai (24.6 million inh.): 555
- Beijing (21.6 million inh.): 517
- Houston (7.2 million inh.): 513
- Guangzhou-Foshan (26.9 million inh.): 505
- Philadelphia-Wilmington (6.5 million inh.): 492
- Boston (4.4 million inh.): 449 (does not include Providence, RI)
- city of Moscow + Moscow oblast (20.9 million inh.): 446
- Atlanta (5.7 million inh.): 427
- Seattle (4.0 million inh.): 427
- Nagoya (8.7 million inh.): 405
- Shenzhen (16.3 million inh.): 394
- Miami-West Palm Beach (6.3 million inh.): 385
- Singapore (5.9 million inh.): 375
- Hong Kong (7.5 million inh.): 363
- city of Moscow (12.7 million inh.): 353
- Toronto-Oshawa (7.5 million inh.): 348
- São Paulo (21.7 million inh.): 318
- Suzhou (12.4 million inh.): 278
- Phoenix (5.0 million inh.): 278
- Detroit (4.4 million inh.): 278
- Minneapolis (3.6 million inh.): 278
- Sydney (5.2 million inh.): 277
- Mexico City (20.4 million inh.): 275
- Madrid (6.9 million inh.): 273
- Chongqing "metropolitan developed economic area" (主城都市区; 20.8 million inh.): 266
- Taipei (9.7 million inh.): 265
- Milan (5.0 million inh.): 261
- Chengdu (20.0 million inh.): 247 (or 281 if Deyang is also added, which is 23.5 million inh.)
- Melbourne (5.0 million inh.): 247
- San Diego (3.3 million inh.): 235
- Denver (3.0 million inh.): 235
- Wuhan (12.0 million inh.): 235
- Munich (3.0 million inh.): 229
- Hangzhou (11.4 million inh.): 225
- Berlin (4.9 million inh.): 218
- Istanbul (13.3 million inh.): 207
- Tianjin (13.7 million inh.): 205
- Amsterdam (2.9 million inh.): 204
- Nanjing (9.1 million inh.): 203
- Dublin (2.1 million inh.): 199
- Brussels (3.3 million inh.): 197
- Ruhr (5.1 million inh.): 194
- Hamburg (3.4 million inh.): 191
- Rome (4.3 million inh.): 187
- Montréal (4.6 million inh.): 185
- Barcelona (5.0 million inh.): 177
- Frankfurt (2.6 million inh.): 171
- St. Louis (2.6 million inh.): 171
- Portland (2.4 million inh.): 171
- Austin (2.2 million inh.): 171
- Perth (Australia) (2.1 million inh.): 171
- Stockholm (2.3 million inh.): 170
- Stuttgart (2.5 million inh.): 163
- Vienna (3.0 million inh.): 158
- Zürich (1.5 million inh.): 152
- Copenhagen (2.1 million inh.): 151
- Rio de Janeiro (12.8 million inh.): 148
- Chongqing "central urban area" (中心城区; 10.1 million inh.): 137
- National Capital Territory (NCT) of Delhi (18.5 million inh.): 114
https://stats.oecd.org/Index.aspx?datasetcode=FUA_CITY