Understanding Salary Increases and Tax in the United Kingdom
When you receive a salary increase in the United Kingdom, the extra income is taxed at your marginal tax rate — the highest bracket your total income falls into. This means you'll keep a smaller percentage of the raise compared to your overall effective tax rate, but you will always take home more in absolute terms.
the United Kingdom's progressive tax system has seven brackets from 18% to 45%. A raise might push part of your income into a higher bracket, but only the amount above the threshold is taxed at the higher rate. You'll never earn less by getting a raise — that's a common misconception about "tax bracket creep."
When evaluating a raise, compare it against inflation (typically 4–6% in SA). A raise below inflation means your purchasing power actually decreases. Also consider that benefits like additional pension contributions or private medical insurance may be more tax-efficient than a straight salary increase, since pension contributions are tax-deductible up to 27.5%.
Frequently Asked Questions
How does a raise affect my tax bracket?
A raise may push part of your income into a higher bracket, but only the amount above the threshold is taxed higher. the United Kingdom uses progressive taxation — your entire salary isn't taxed at the new rate. You always take home more money with a raise.
What is the average salary increase in the United Kingdom?
Average increases typically range from 4% to 7% per year, roughly matching inflation. Top performers may receive 8–12%. Any raise below the inflation rate (CPI) means your real purchasing power is decreasing year-on-year.
Does a raise change my National Insurance contribution?
National Insurance is 1% of gross salary, capped at £50,270/month (ceiling of £12,570). If you already earn above £12,570, a raise won't increase your National Insurance. If you're below the ceiling, National Insurance will increase by 1% of the raise amount.
How much of my raise do I actually keep?
You keep roughly 100% minus your marginal tax rate minus 1% National Insurance (if below ceiling). In the 26% bracket, you keep about 73%. In the 31% bracket, about 68%. The higher your bracket, the less of each extra rand you keep.
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