How is the savings time calculated?
The calculator uses the future value formula to find the number of months needed: n = log((FV × r/PMT) + 1) / log(1 + r), where FV is your target, PMT is your monthly contribution, and r is the monthly interest rate. If your rate is 0%, it simply divides the remaining amount by your monthly contribution.
What interest rate should I use for a savings account?
For a high-yield savings account or cash ISA, use the current rate you're earning — typically 4–5% in 2024. For a stock market investment with a longer time horizon (5+ years), 6–8% is a reasonable assumption. Use a lower rate to be conservative.