Short answer, yes it is…
The State Pension is worth between £6,359.60 (the old version), and £8,296.60 (the new version), and many pensioners may receive additional payments based on additional contributions made in prior years. In both cases, this pension income is treated the same as earned income for income tax purposes.
For 2017-18, every person resident in the UK for tax is allowed to earn £11,500 tax free. Accordingly, if your only source of income is the State Pension you will have no tax to pay. A potential problem can arise if you have other income, say taxable investment income or other earnings, that when combined with your State Pension, add to more than your personal allowance.
Your State Pension is paid to you without a deduction of tax. Many pensioners rely on these payments to fund their day to day expenditures so there is a temptation to spend what you get. Unfortunately, if your total income (State Pension plus other earnings and investment income) exceeds your personal allowance, you may end up with a tax bill at the end of the tax year and the first you may hear about this is when the bill from HMRC drops through your letter box.
Our advice, is do the sums. If your estimated income from all sources is likely to exceed £11,500 for 2017-18, you may need to save for any year-end tax due. The sums can be complicated as there are reliefs other than your personal tax allowance that you may need to consider.