How much could £1,666 a month in a Stocks and Shares ISA be worth in 20 years?

A UK Stocks and Shares ISA could turn £1,666 invested every month into a portfolio worth hundreds of thousands after 20 years, largely depending on returns. With the annual ISA allowance currently set at £20,000, £1,666 per month fits the limit without tax on dividends or capital gains. If contributions continue for 20 years, total deposits reach £399,840. In one scenario using a steady 5.5% dividend yield, reinvesting payouts and assuming no share-price growth, the portfolio could reach about £726,000. About £326,000 would come from compounding, with nearly £40,000 of annual dividends if contributions stop. The calculations exclude fees and assume a constant yield.