Tool/App for calculating tax owed in real time or a per job/employment basis

maracles

I am looking for a website, app or other tool (free or paid) that will allow me to enter my earnings and deductions on an employment by employment basis as I get paid throughout the tax year - with the goal being that I know on any given day exactly how much tax I owe at that point, and how much of the tax owed has been deducted. 

I work in multiple industries, one of which is the film industry which has to follow rather ridiculous government guidelines on how freelancers are employed, this means that I can be employed by upwards of 20-30 individual companies in a given year because the government mandates that even if I am working for a single day I need to be processed as PAYE and then let go at the end of that single day job. So I have a mix of this, plus a steady full-time employment, plus some other freelance self-employed work and trying to keep estimates on how much tax is outstanding is a bit of a nightmare, I would love a realtime way of doing this. I'm aware of LP-10 letters, but these aren't always simple to obtain. 

I have discovered GoSimpleTax, which does something similar but I've found it has restrictions that stop me using it and can be buggy.