CTERM

Returns the number of compounding periods required for an investment at a present value to reach a future value earning a fixed interest rate.

Syntax:

CTERM(interest:number, future_value:number, present_value:number)

where:

interest is the interest rate per period, expressed as a decimal fraction;
future_value is the desired future value of the investment;
present_value is the present value of the investment.

Formula:

CTERM = LN(future_value< ÷ present_value) ÷ LN(1 + interest)

Example:

How long would it take for £1000 to grow into £2000 at an interest rate of 10% per annum?

The formula

CTERM(0.10, 2000, 1000)

returns the number of periods, 7.27 (years).