It is impossible to estimate the amount of Bitcoin which are lost forever. If you want to calculate this amount, you must make a big global analyze. however, Bitcoin is used anonymously by many organization and individual, which means we can never know exact data because there will be people who are not willing to provide the information about bitcoin they have lost.

Obviously lot of bitcoin had been lost in human destruction like pc crashed, hard disk formatted, virus affected, lost device and lot of reasons. May be one had store bitcoin in paper wallet and later the paper got wet. I think I should not mention reasons here everyone know well that lot of bitcoin is lossed

I wonder how the people would feel like if they really did not give any importance to their bitcoins at that time and they see the price now, but that is actually right, a lot of people would have given no importance to it by thinking it's worth nothing and they have left their wallets with the coins and forgot the passwords or private keys and those bitcoins are locked their forever.

Well sure, technically the Bitcoins are not lost until they get permanently burned. However, if you lost the private keys of your Bitcoins then it is very likely that they will never ever be transferred again. So those Bitcoins are acutally out of the "game".

Well that's a good question to investigate! I guess that is very difficult to know at this point because no one gave report if lossed bitcoin. I think that we will only be able to find how many BTC are lost after they are all mined. Or we can probably research the blockchain legldger and find a pattern that could lead us to see how many BTC could be outside of the. And many user forget wallet id so some amount is loosed in that way

Well i have just learned new things today/yesterday about some bitcoin addresses i had found something, Here are some btc addresses that receive bitcoins but these can't be spent, for more information about have a check at this thread https://bt.irlbtc.com/view/1168745.0

I guess it should be so many of bitcoin that lost forever around BTC1-100 as we don't know for sure, so just let us know how much it is in your opinion. Unfortunately, blockchain technology created so secure and give control to user of their wallet and no one could know how much btc inside even admin of blockchain. Moreover, there are plenty of wallet sites and we don't know which one that have been lost their private key, so no answer about this just lucky guess.

its not possible to answer this question until we just count all the old addresses and see how much balance they have un transacted for years . that can also be someone saving money for a long term investment but lets take it now as lost bitcoin which can not be recovered anyhow

Maybe there isn't a big number of lost bitcoins but there is much big number of lost wallet keys and passwords, hard drive damages and etc, all this facts causes lost of bitcoin. We can't say specified number of lost bitcoins but there is some ways to discover it's nearly number. If person hasn't made transactions for 12 months or more, there is high chanse that wallet and bitcoin is lost. I think there must be some similar tools in blockchain to know number of lost bitcoins and that bitcoins must be remade because it's lost and lost things can be founded.

I also think that there is always a way out of a difficult situation, and above all there are opportunities to get back into your wallet. Thus, this option is already eliminated. But there are times when people just stop using purse and lose sight of him, along with the content. But I can not understand how it burned bitcoin?