Tax calculators

Hi,

I have searched high and low online for a decent tax calculator for self assessment tax returns.They are all very basic!

I have income from a variety of sources: interest on savings, dividend from my company, small pension payments which are taxed through PAYE at source, and a salary from my company which also goes through PAYE.

Rather than having to wait until I complete my self assessment return next year, it would be very helpful to know what my tax liability will be - using the same calculation as HRMC - before the event, so I can plan ahead.

Any help would be much appreciated!