Course Outline
Join PRO

What happens when the high-low method ends up with a negative amount?

Harold Averkamp, CPA, MBA

The high-low method of determining the fixed and variable portions of a mixed cost relies on only two sets of data: 1) the costs at the highest level of activity, and 2) the costs at the lowest level of activity. If either set of data is flawed, the calculation can result in an unreasonable, negative amount of fixed cost.

To illustrate the problem, let’s assume that the total cost is $1,200 when there are 100 units of product manufactured, and $6,000 when there are 400 units of product are manufactured. The high-low method computes the variable cost rate by dividing the change in the total costs by the change in the number of units of manufactured. In other words, the $4,800 change in total costs is divided by the change in units of 300 to yield the variable cost rate of $16 per unit of product. Since the fixed costs are the total costs minus the variable costs, the fixed costs will be calculated to a negative $400. This unacceptable answer results from total costs of $1,200 at the low point minus the variable costs of $1,600 (100 units times $16), or total costs of $6,000 at the high point minus the variable costs of $6,400 (400 units times $16).

The negative amount of fixed costs is not realistic and leads me to believe that either the total costs at either the high point or at the low point are not representative. This brings to light the importance of plotting or graphing all of the points of activity and their related costs before using the high-low method. (The number of units uses the scale on the x-axis and the related total cost at each level of activity uses the scale on the y-axis.) It is possible that at the highest point of activity the costs were out of line from the normal relationship?referred to as an outlier. You may decide to use the second highest level of activity, if the related costs are more representative.

If the $6,000 of cost at the 400 units of activity is an outlier, you might select the next highest activity of 380 units having total costs of $4,000. Now the variable rate will be the change in total costs of $2,800 ($4,000 minus $1,200) divided by the change in the units manufactured of 280 (380 minus 100) for a variable rate of $10 per unit of product. Using the variable rate of $10 per unit manufactured will result in the fixed costs being a positive $200. The positive $200 of fixed costs is calculated at either 1) the low activity: total costs of $1,200 minus the variable costs of $1,000 (100 units at $10); or at 2) the high activity: total costs of $4,000 minus the variable costs of $3,800 (380 units at $10).

Join PRO to Track Progress
Must-Watch Video

Learn How to Advance Your Accounting and Bookkeeping Career

  • Perform better at your current job
  • Refresh your skills to re-enter the workforce
  • Pass your accounting class
  • Understand your small business finances
Watch the Video

Join PRO or PRO Plus and Get Lifetime Access to Our Premium Materials

Read all 2,645 reviews



PRO Plus

Lifetime Access (One-Time Fee)
Word Scrambles
Bookkeeping Video Training
Financial Statements Video Training
Visual Tutorials
Quick Tests
Quick Tests with Coaching
Cheat Sheets
Business Forms
All PDF Files
Progress Tracking
Earn Badges and Points
Certificate - Debits and Credits
Certificate - Adjusting Entries
Certificate - Financial Statements
Certificate - Balance Sheet
Certificate - Income Statement
Certificate - Cash Flow Statement
Certificate - Working Capital
Certificate - Financial Ratios
Certificate - Bank Reconciliation
Certificate - Payroll Accounting

About the Author

Harold Averkamp

For the past 52 years, Harold Averkamp (CPA, MBA) has worked as an accounting supervisor, manager, consultant, university instructor, and innovator in teaching accounting online. He is the sole author of all the materials on

Learn More About Harold

Certificates of

Certificates of Achievement

We now offer 10 Certificates of Achievement for Introductory Accounting and Bookkeeping:

  • Debits and Credits
  • Adjusting Entries
  • Financial Statements
  • Balance Sheet
  • Income Statement
  • Cash Flow Statement
  • Working Capital and Liquidity
  • Financial Ratios
  • Bank Reconciliation
  • Payroll Accounting
Badges and Points
  • Work towards and earn 30 badges
  • Earn points as you work towards completing our course
View PRO Plus Features
Course Outline
Take the Tour Join Pro Upgrade to Pro Plus