what you're looking for is something simple to make yourself by using a spreadsheet. You would just need to manually enter the Bitcoin value and have the result calculated automatically
I guess OP is looking for a specific tool which answers the question, "how much would my Bitcoin be worth if its price is $______?" So the input would be OP's total Bitcoin holdings and the speculative price of Bitcoin. Blockfolio does not provide that. Just like the rest, it provides real time Bitcoin price.
If OP really wants to keep track, spreadsheet is his/her best option. There is automatic update or computation with spreadsheet as far as his/her worth is concerned based on a specifically determined Bitcoin's price, not the real time price.
Or are we just making things complicated? Why not just use an ordinary calculator? It takes only a few seconds.