It depends on the type of investment account. The tax-free allowance for stocks and shares ISAs or cash ISA is £20,000. The tax-free allowance for lifetime ISA is £4,000, while the tax-free allowance for junior ISA or child trust fund is £9,000. You get 25% of your pension pot tax-free. For children’s pension, the tax-free amount is £2,880. For bank and building society accounts, the first £500 to £1,000 you earn from savings is tax-free, depending on your income tax bracket. EIS, SEIS, VCT, and SITR have different tax relief amounts.