It says a Big Mac in the U.S. is $5.81 which sounded high. Popped open the McDonalds app and sure enough I can get one for $4.39 plus a free medium fry. Prices must not be uniform across the U.S., but I find it hard to believe the average is $5.81.
The website has a reference for where they get their big mac prices:
> Big Mac Index measures the average price of a Big Mac at McDonald's in the United States and is famously used in the Economist's Big Mac Index to measure inflation.
And a link to the Economist article (https://www.economist.com/big-mac-index) where they further link to their methodology: https://github.com/TheEconomist/big-mac-data
The USA average seemed high to me, and I found this resource: https://www.zippia.com/advice/how-much-big-mac-costs-states/ - Nov 2021 - which suggests $4.40. But the Economists data/csv file really does say $5.81 for the USA... so that's where I bow out!