Quick answer

Cell formula: (f_b − f_a)/(b − a) using endpoint references.

Formula

  • =(B2-B1)/(A2-A1) example with two rows

Introduction

Set up cells for inputs and outputs, then compare with the Average Rate of Change Calculator when you want a quick graph.

If you need the full method list first, read how to calculate average rate of change for manual and graph checks.

For interface tips on the web tool, open the calculator guide after your sheet formula works.

Keep first and last data rows as endpoints when you want results that match this site’s table formula.

Sheet layout

Column A for inputs (time, x, quarter index). Column B for outputs (position, f(x), revenue).

Use clear headers so you do not swap columns when writing the fraction.

For long tables, highlight endpoint cells in color to avoid referencing middle rows by mistake.

Google Sheets uses the same syntax as Excel for this calculation.

Formula cell patterns

  • =(B_last-B_first)/(A_last-A_first)
  • Named cells: =(f_b-f_a)/(b-a) for presentations

Lock references with $ when copying across columns if your template requires it.

Format cells as numbers, not text, before subtracting.

  1. Type data without text in numeric cells. Apostrophes or stray symbols break subtraction.
  2. Reference endpoints explicitly. Point the formula to first and last rows you intend, not arbitrary highlights.
  3. Label units in adjacent cells. Readers should see dollars per quarter or meters per second beside the rate.
  4. Verify with the calculator. Enter the same two endpoints online and confirm the rate and secant graph.
  5. Document the interval. Add a short note cell describing the reporting window.

Mini sheet

A1=1, B1=4, A2=5, B2=16. Formula =(B2-B1)/(A2-A1) yields (16−4)/(5−1)=3.

Add a third row only if you understand whether the question wants first-to-last endpoints.

Copy the same pair into the calculator to see the dashed data segment and solid secant line.