Calculates the interest rate of an annuity investment based on constant-amount periodic payments and the assumption of a constant interest rate.

**Sample Usage**

RATE(12,-100,400)

RATE(C5,C6,C7)

**Syntax**

RATE(total_periods, payment_amount, present_value, [future_value], [type], [rate_guess])

- total_periods - The total number of payment periods.
- payment_amount - The amount to be paid per period.
- present_value - The current value of the annuity.
- future_value - [OPTIONAL] The future value remaining after the final payment has been made.
- type - [OPTIONAL] The due date type for the payment – at the beginning (0) or end of each period (1).
- rate_guess - [OPTIONAL] An estimate of the interest rate. If unspecified, it defaults to 0.1.

**Examples**

RATE(12,-100,400) calculates the interest rate of the annuity investment.