Primary Market | What’s the difference between circulating supply, total supply, and maximum supply?
Different data websites may use different criteria to calculate “circulating supply,” so the figures for the same coin may vary from site to site.
When a coin’s circulating supply is only a small fraction of its maximum supply, a substantial amount may still be released over time. In that case, it’s worth looking at the unlock schedule as well.
The maximum supply of $BTC is fixed at 21 million coins, and the number already mined is gradually approaching that limit. Currently: 82664.
Be wary of projects that claim to offer stable, high returns.

Just my personal take—it may not be accurate, so please use your own judgment.