£50 when I was 14 was worth £90 in today's money. Buffett's $5k was $68k.
Buffett's age-35 7M was worth 53M in today's money. So I'd need £70k in today's money to match his net worth growth.
That's exactly the same. I'm actually surprised by this, as it suggests both Buffett and I experienced the same level of compound inflation over the 20 years of our lives from age 14, despite being at different times and on different continents.
(This is all tongue-in-cheek, of course).