Concrete calculators can be found for free at home improvement stores or websites. However, these are used as a tool only and may not be exact. In general you will need a very close estimation of the surface you need to cover.
You can find information about interest only calculators at the following websites...www.mortgagecalculator.org/calculators/interest-only-calculator.php
The best investment calculators, and general finance calculators, are all found online at BankRate.com. This is the best website for calculators, in my personal opinion.
One can find mortgage refinancing calculators at a website called Realtor. Other websites that one can find mortgage refinancing calculators at include Zillow and CGI.
Online calculators are extremely easy to find. You can even find fully functioning scientific calculators on the internet that use java. Just do a google search for calculators and you will find plenty.
One can find information on annuity calculators by going to the place that provides them. Examples of places that provide annuity calculators would be Bankrate, Aviva and LifeAnnuities.
It is possible to find free online calculators here at HR Block, Turbo Tax and Money Saving Expert for tax calculators. For Math calculators, one can get free online Math solvers at Math Portal.
You may find out about early mortgage payout calculators at the following websites...www.bankrate.com/calculators/.../early-payment-payoff-calculator.as... or loan.bizcalcs.com/Calculator.asp?Calc=Loan-Early-Payoff
There are lots of websites online where you will find amortization mortgage calculators. A couple I recommend are www.hsh.com Calculators and bretwhissel.net/amortization/.
You can find online refinancing calculators for free. You can go to www.calculators4mortgages.com/ for online refinancing calculators. You can also go to www.mortgagecalculator.org/.
There are many different websites online that have bi monthly mortgage calculators. Www.bankrate.com/calculators or www.hsh.com Calculators are two I recommend.
Savings interest calculators tell you how much money you will earn from interest on your savings. To find out more information on savings interest calculators go to www.moneyadviceservice.org.uk where you will find all the details you require.
You can find online retirement calculators at moneycentral.msn.com/retire/planner.aspx and www.bloomberg.com/invest/calculators/retire.html. Fool.com and Vanguard offer free retirement calculators. These can help calculate how much you'll have at retirement.