When is my money worth more in savings vs overpaying the mortgage?

Skytunnel31

I read an article not so long ago which said (without explanation) that your savings rate would have to be at least double your mortgage rate before it is worth while keeping it in savings vs paying off your mortgage.

But I fail to understand why this would be?

I can get a mortgage with a pretty low rate right now, and although not double, I can get regular savers account earning as much as 2.75%.

Let's say the mortgage rate was 1.75%, then if you were able to save the max £500 a month at 2.75% it would be equivalent to offseting £785.71 of the mortgage loan for the length of the savings rate.  Therefore doesn't it have more value in savings than in the mortgage?  Unless I am missing something?  

Do you agree or disagree?  Or how much above the mortgage rate would your savings have to be before you consider it worthwhile?

I would personally consider it worthwhile if it's at least 20% above the mortgage rate.  What about you?

bricoleur

there's a calculator here, and a good guide. 
moneysavingexpert.com/mortgages/mortgages-vs-savings/