# FORECAST

The `FORECAST` function in Google Sheets is a statistical function that predicts a future value along a linear trend. It returns the predicted value for a chosen x value based on the linear regression of a set of known x and y values. This function is commonly used in finance to predict future values.

## Usage

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

Parameters:
1. x (required):
The x value for which you want to predict the corresponding y value.
2. data_y (required):
An array or range of the y values in the data set.
3. data_x (required):
An array or range of the x values in the data set, corresponding to the y values in the `data_y` parameter.

## Examples

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

### Predicting future sales

A business can use `FORECAST` to predict future sales based on previous sales data. By inputting the known sales values as `data_y` and the corresponding time period as `data_x`, a business can predict future sales by inputting a future time period as `x`.

### Budget forecasting

A company can use `FORECAST` to predict future costs or revenue based on previous data. By inputting the known cost or revenue values as `data_y` and the corresponding time period as `data_x`, a business can predict future costs or revenue by inputting a future time period as `x`.

### Stock price prediction

Investors can use the `FORECAST` function to predict the future stock price of a company based on its past performance. By inputting the known stock prices as `data_y` and the corresponding time period as `data_x`, investors can predict future stock prices by inputting a future time period as `x`.

## Common Mistakes

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

### Incorrect data range

One common mistake is to select the wrong data range for the data_y and data_x arguments. Make sure the data ranges are correct and include all the necessary data points.

### Non-numeric input

Another mistake is to include non-numeric values in the data_y and data_x ranges. Make sure all values are numeric and formatted as numbers.

### Insufficient data points

If there are not enough data points in the data_y and data_x ranges, the forecast may be inaccurate or not possible. Make sure there are enough data points for an accurate forecast.

### Incorrect x value

Make sure the x value used in the formula is within the range of the data_x values. Using an x value outside of this range will result in an inaccurate forecast.

### Missing arguments

Make sure all three arguments (x, data_y, and data_x) are included in the formula. Leaving out any of these arguments will result in an error.

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

• `TREND`

The `TREND` formula is used to calculate future values based on historical data. It fits a straight line (using the method of least squares) to the arrays specified in the `known_data_y` and `known_data_x` parameters and then uses that line to calculate new y-values for the array specified in the `new_data_x` parameter. If `b` is set to TRUE, then the calculation will include the y-intercept of the line. This formula is commonly used in forecasting and trend analysis.

• `LINEST`

The `LINEST` formula is used to calculate the statistics for a line by calculating the line's slope and y-intercept. It is commonly used to find the best-fit straight line for a given set of data points.

• `SLOPE`

The `SLOPE` formula calculates the slope of the linear regression line that best fits the input data. It is commonly used in statistics to analyze trends and predict future values based on past performance.

• `INTERCEPT`

The `INTERCEPT` function calculates the point where the line of best fit for a set of data intercepts the y-axis. This function is commonly used in regression analysis to find the constant b in the equation y=mx+b where m is the slope of the regression line.

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