# PDURATION

The `PDURATION` function calculates the number of periods required for an investment to reach a specific future value, based on a constant interest rate per period. This function is commonly used in financial analysis and planning, especially in retirement planning.

## Usage

Use the `PDURATION` formula with the syntax shown below, it has 3 required parameters:

Parameters:
1. rate (required):
The interest rate per period of the investment. This rate should be consistent across all periods.
2. present_value (required):
The present value of the investment.
3. future_value (required):
The future value that the investment is expected to reach.

## Examples

Here are a few example use cases that explain how to use the `PDURATION` formula in Google Sheets.

### Retirement planning

A user can use `PDURATION` to determine how many periods they need to save for retirement in order to achieve a certain level of wealth.

### Loan repayment planning

A user can use `PDURATION` to determine how many periods they need to budget for in order to pay off a loan with a specific interest rate and principal amount.

### Savings planning

A user can use `PDURATION` to determine how many periods they need to save for in order to achieve a specific savings goal with a given interest rate.

## Common Mistakes

`PDURATION` not working? Here are some common mistakes people make when using the `PDURATION` Google Sheets Formula:

### Incorrect order of arguments

The arguments for the PDURATION formula must be entered in the correct order. The correct order is rate, present value, and future value. If the order of the arguments is incorrect, the formula will return an error.

### Missing arguments

All three arguments for the PDURATION formula must be provided. If any of the arguments are missing, the formula will return an error.

### Invalid data type

The rate, present value, and future value arguments must be numeric values. If any of the arguments are not numeric, the formula will return an error.

### Incorrectly formatted arguments

The rate, present value, and future value arguments must be properly formatted. If any of the arguments are not formatted correctly, the formula will return an error. For example, the rate argument should be entered as a percentage.

### Negative value for time period

If the rate is greater than 0 and the future value is less than the present value, the PDURATION formula will return a negative value. This indicates that the investment will never reach the future value. In this case, the formula should not be used.

The following functions are similar to `PDURATION` or are often used with it in a formula:

• `FV`

The `FV` function calculates the future value of an investment based on periodic constant payments and a constant interest rate. It takes into account the present value of the investment, the number of periods in which the payments are made, and the compounding frequency. This formula is commonly used in financial planning and investment analysis.

• `PV`

The `PV` function in Google Sheets calculates the present value of a regular payment stream or a lump sum amount, based on a constant interest rate. It is commonly used in financial analysis to determine the value of investments or loans. This function returns a negative value, as it represents money flowing out from the user.

• `NPER`

The `NPER` function calculates the total number of payment periods required to pay off an investment based on a constant payment amount, a fixed interest rate, and the present value of the investment. It is commonly used in financial planning and investment analysis.

• `RATE`

The `RATE` formula returns the interest rate per period of an annuity. This formula is often used in financial analyses to calculate the rate of return on an investment. It assumes that payments are made at regular intervals and that the interest rate remains constant throughout the duration of the annuity.

You can learn more about the `PDURATION` Google Sheets function on Google Support.