INTERCEPT function

This article describes the formula syntax and usage of the INTERCEPT function (function: A prewritten formula that takes a value or values, performs an operation, and returns a value or values. Use functions to simplify and shorten formulas on a worksheet, especially those that perform lengthy or complex calculations.) in Microsoft Excel.

Description

Calculates the point at which a line will intersect the y-axis by using existing x-values and y-values. The intercept point is based on a best-fit regression line plotted through the known x-values and known y-values. Use the INTERCEPT function when you want to determine the value of the dependent variable when the independent variable is 0 (zero). For example, you can use the INTERCEPT function to predict a metal's electrical resistance at 0°C when your data points were taken at room temperature and higher.

Syntax

INTERCEPT(known_y's, known_x's)

The INTERCEPT function syntax has the following arguments (argument: A value that provides information to an action, an event, a method, a property, a function, or a procedure.):

  • Known_y's    Required. The dependent set of observations or data.
  • Known_x's    Required. The independent set of observations or data.

Remarks

  • The arguments should be either numbers or names, arrays, or references that contain numbers.
  • If an array or reference argument contains text, logical values, or empty cells, those values are ignored; however, cells with the value zero are included.
  • If known_y's and known_x's contain a different number of data points or contain no data points, INTERCEPT returns the #N/A error value.
  • The equation for the intercept of the regression line, a, is:

Equation

where the slope, b, is calculated as:

Equation

and where x and y are the sample means AVERAGE(known_x's) and AVERAGE(known_y's).

  • The underlying algorithm used in the INTERCEPT and SLOPE functions is different than the underlying algorithm used in the LINEST function. The difference between these algorithms can lead to different results when data is undetermined and collinear. For example, if the data points of the known_y's argument are 0 and the data points of the known_x's argument are 1:
    • INTERCEPT and SLOPE return a #DIV/0! error. The INTERCEPT and SLOPE algorithm is designed to look for one and only one answer, and in this case there can be more than one answer.
    • LINEST returns a value of 0. The LINEST algorithm is designed to return reasonable results for collinear data, and in this case at least one answer can be found.

Example

The example may be easier to understand if you copy it to a blank worksheet.

ShowHow do I copy an example?

  1. Select the example in this article. If you are copying the example in Excel Online, copy and paste one cell at a time.
    Important: Do not select the row or column headers.

Selecting an example from Help

Selecting an example from Help

  1. Press CTRL+C.
  2. Create a blank workbook or worksheet.
  3. In the worksheet, select cell A1, and press CTRL+V. If you are working in Excel Online, repeat copying and pasting for each cell in the example.
    Important: For the example to work properly, you must paste it into cell A1 of the worksheet.
  4. To switch between viewing the results and viewing the formulas that return the results, press CTRL+` (grave accent), or on the Formulas tab, in the Formula Auditing group, click the Show Formulas button.

After you copy the example to a blank worksheet, you can adapt it to suit your needs.

 
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Formula Description (Result)
=INTERCEPT(A2:A6, B2:B6) Point at which a line will intersect the y-axis by using the x-values and y-values above (0.0483871)
 
 
Applies to:
Excel 2010, Excel Web App, SharePoint Online for enterprises, SharePoint Online for professionals and small businesses