ISA Switch Calculator

Our ISA switch calculator shows whether moving to a higher-rate ISA leaves you better off. Transfers preserve your allowance — you do not lose tax-free status by switching provider.

Enter the balance in your current ISA, the existing rate, and the rate offered by the new ISA provider. The calculator shows the interest difference annually and the accumulated saving over your chosen period. ISA transfers preserve your tax-free status — you must use an official ISA transfer rather than withdrawing and redepositing, which would use your current year’s allowance. Transfers typically take 15 working days for cash ISAs and longer for stocks and shares. During the transfer period, no interest is usually paid, so factor this into the comparison — a slightly higher rate may not compensate for a long transfer period if it is a significant amount. Most providers now offer flexible ISAs that allow withdrawals and redeposits within the same tax year without affecting the annual limit.