I am wondering how much one can save for retirement.How much is enough?Its a very hard thing to come up with because you dont know about the future.So which is the best way to estimate the amount?

The first thing to determine is exactly what you mean by retirement. If you mean you intend to quit working completely, then you better have a large amount of money set aside. Keep in mind that you probably "need" to spend atleast $1500 a month. That's $18,000 per year. And that's just getting by.

I don't think it's much as that there's a ceiling on retirement savings as much as that most people fall under a require minimum - plus pensions schemes have generated an image of being unreliable.

Also depending on your country, there are life insurance that works like long-term inversion.

If you survive after the number of years signed in the policy, they pay you the value of the insurance plan plus accrued interests so you can have funds for retirement.

The amount you need will depend upon other funds you have to fall back on when you are of a certain age. Does your work offer a retirment package for example. In the US you will also qualify for Social Security at a certain point.