How much tax will you pay if you take a second job?

Out of a total UK workforce of more than 30m, about 1.18m of us have a second job. Over the past 20 years, the number of people with a second job, either through choice or necessity,…

5 Minute Read

Last Updated: 5th April 2023

Out of a total UK workforce of more than 30m, about 1.18m of us have a second job. Over the past 20 years, the number of people with a second job, either through choice or necessity, has been rising steadily.

Maybe you already have a full-time or part-time job, but you’re considering taking another one to boost your income. You may be wondering whether you have to let HMRC (the UK tax authority) know about your second income and how much tax you will pay. Read on to find out.


When you leave a job, your employer should give you a P45, a slip of paper that details key facts such as your date of birth, name, address, National Insurance number, tax code, tax paid on your salary so far in the tax year, etc.

If you’re not leaving a job, just starting to work for another employer, you’ll need to complete a Starter Checklist for PAYE and send or give it to your second employer so they can work out your correct tax code before adding you to their payroll. Alternatively, your new employer may send you a paper Starter Checklist for PAYE to complete.

A tax code enables employers to know how much tax-free income you can earn, so that they can deduct the right amount of Income Tax and National Insurance contributions (NICs) from the rest of your earnings.

Need to know! As an employee, you do not have to contact HMRC about your second job. HMRC will find out when your second employer registers you for tax via their payroll.


HMRC will consider one job as your main income source and you’ll get a personal allowance for this. The standard Personal Allowance is £12,570 and you don’t pay tax on earnings up to this amount. If you claim Marriage Allowance or Blind Person’s Allowance it will further increase your tax-free earnings.

Earnings over the Personal Allowance threshold are subject to Income Tax at:

BandTaxable income    Tax rate
Personal Allowance   Up to £12,5700%
Basic rate £12,571 to £50,27020%
Higher rate£50,271 to £125,14040%
Additional rateOver £125,140

Need to know! It’s best to have your Personal Allowance applied to the job that pays you the most money. If you earn less than £12,570 from both of your jobs, to minimise how much tax you’ll pay, ask HMRC to split your Personal Allowance across both jobs.

Second-job earnings are often taxed using a BR (ie basic rate) tax code, which is 20%. But if your second job is very well paid, your tax code can be D0 (higher rate) or D1 (additional rate), which means you’re paying tax at a higher rate (40% or 45%).


If you earn more than £190 a week in the 2022/23 tax year, you’ll have to pay Class 1 National Insurance contributions (NICs). If you earn more than this figure in each of your jobs, you’ll pay NICs on both at:

  • 12% on earnings of £190 to £967 a week (£823 to £4,189 a month)
  • 2% on earnings of more than £967 a week (£4,189 a month).

Your employers deduct your Class 1 NICs from your earnings and pay them to HMRC on your behalf.


Rather than take another job, many people now start their own part-time business (sometimes called a “side-hustle”) to supplement their main or day jobs. If you set up a self-employed business (rather than a limited company), unless earnings are less than £1,000, you’ll need to register for Self Assessment with HMRC.

Self Assessment is the system HMRC uses to collect tax from self-employed people. Each year, you must complete and file a Self Assessment tax return (service providers will do it for you), detailing your earnings and costs, so that the Income Tax and NICs that you owe can be calculated. You must then pay these directly to HMRC.

Need to know! You can get up to £1,000 each tax year in tax-free allowances for property or trading income. If you earn income from both sources, you’ll get a £1,000 allowance for each. If your annual gross property income is £1,000 or less, you don’t have to tell HMRC or declare this income on a tax return.

Trusted by over 15,000 subscribers

You don't need to be an expert to complete your self assessment tax return.

Start your free trial

Blog content is for information purposes and over time may become outdated, although we do strive to keep it current. It's written to help you understand your Tax's and is not to be relied upon as professional accounting, tax and legal advice due to differences in everyone's circumstances. For additional help please contact our support team or HMRC.


Start your Self Assessment tax return today for free.

Sign up Now

20 common tax and accounting terms that sole traders should understand

06 Jun 2023

Although you’ll no doubt have an expert knowledge of your trade or profession, your understanding of tax and accounting could be fairly limited. That’s…

Seasonal business owners: 21 things you need to know about sole trader tax

05 Jun 2023

Some business ideas just aren’t viable throughout the year, because the weather at certain months seriously weakens demand or kills it altogether. However, running…

How much tax does a landlord need to pay? 10 key questions answered…

18 May 2023

The UK has more than 2.7m unincorporated landlords and each year they report to HMRC rental property income worth some £41bn. Unincorporated landlords are…

How GoSimpleTax Works


Simply register for free with your full name and email address.

Select Your Income

Select the income you receive and follow the hints and tips for potential tax savings.

Validate Your Information

Validate your personal information and submit directly to HMRC to get confirmation in just seconds.


Work Anywhere, With Any Device

Gone are the days of fretting over a calculator surrounded by scraps of paper at the eleventh hour.

GoSimpleTax’s tax return software uses the information you upload in real time to calculate your income and expenditure, working out the tax you owe and sending you helpful notifications when there’s the possibility of a mistake.

Start your free trial

"The software is intuitive and proved very easy to navigate. I found the whole process refreshingly simple. I saved a lot of money too!"

Steve J.

Ordained Presbyter

"Easy to use and value for money. Everything you need to do your tax."

Gordon J.

Self Employed

"It fills in all the forms and sends them to the Inland Revenue. Not expensive either. Takes the stress out of doing your tax return online."

Ross G.

Team Rector

Start your free trial