# Internal Rate of Return Calculator

This page calculates the Internal Rate of Return (IRR) for an investment, given the cash flows for each period. Click the Help tab for full instructions on how to use this tool.

The IRR Calculator is used to calculate the Internal Rate of Return of an investment, given the cash flows for each period.

**Income from Periods** - Each value represents the income received from that period. Negative values represent money invested in the project.

Typically you will have large initial investment, so the value for period 0 will probably be a negative number. Then you may have a series of positive values, representing your returns over several periods. Any further investments in the project will be negative values.

When entering values, you can use whatever currency you like, as long as both values are in the same currency. You don't need to use a currency symbol such as $ or £ (and doing so will cause an error).

Click the **+** button to add another period. Another field will appear on the form to allow you to enter another value for that period.

## Using the Calculator

Click the **Calculate** button to calculate the Internal Rate of Return. The value will be shown below the button.
In some cases it may not be possible to calculate an IRR, or there may be multiple possible IRR values.
This calculator is able to calculate all possible IRR values and will display them on the page.

If any of the values have been entered incorrectly an error message will be displayed next to the field.
Fix the error, then click **Calculate** again to perform the calculation.

Click the **Clear** button to clear all data from the form and start again.