Payments on Account: If your total tax and NI bill exceeds £1,000, HMRC requires you to make two advance payments towards next year's bill. Each payment is 50% of your current year's total liability (income tax + Class 2 + Class 4 + student loan). Due dates: 31 January and 31 July.

Select Year: This salary calculator has the capability to display your pay details, as they would have been, back as far as 1999. Remember that the tax year begins on April 6th of each year

Tax Region: From the 2017/2018 tax year, scottish parliament has set its own tax rates and bands.

Student Loan Repayment: If you were a student, and availed of a student loan, you will begin to repay this loan once your earnings go above a certain threshold. This years threshold begins at £15,000. Student loans will be repaid at a rate of 9% of the additional income over and above this threshold. Click to include the repayment in your calculations.

Allowable Expenses: Enter your total allowable business expenses here. These are deducted from your turnover before calculating your taxable profit. Examples include office costs, travel, equipment, and professional fees.

Annual Turnover: Enter your total annual income from self-employment before any expenses are deducted.

Tax Summary: Select the columns you would like to display on the tax summary table.

Pension: If you currently have a pension enter the amount that you contribute on a regular basis. This can be entered in a percentage format e.g. 4%, or in a numeric format e.g. 500. Self-employed pension contributions are made on a relief-at-source basis — your pension provider claims basic rate tax relief from HMRC on your behalf.