In part 2 of my video series about how to use spreadsheets I showed you some formula examples using absolute formulas ($ dollar sign in formulas). Here's the spreadsheet I used so you can have a play along.
Here's the tax and NI calculator I used on this recent video so that you can play along at home. It's just designed for smaller businesses and doesn't cater for higher tax bands or more complex tax scenarios.
You might have already seen the public article all about pro forma invoices. In this special members only post you can download the actual pro forma invoice template that I use for customers.
This is a really useful spreadsheet that I use to track all of my income and outgoings. It generates enough information for most small businesses to give to their accountants.
Here's a sample invoice and quote template for Excel that I use with actual customers. It's worked fine for me over the years and you can modify them to suit your needs.