Department of Energy Argonne National Laboratory Office of Science NEWTON's Homepage NEWTON's Homepage
NEWTON, Ask A Scientist!
NEWTON Home Page NEWTON Teachers Visit Our Archives Ask A Question How To Ask A Question Question of the Week Our Expert Scientists Volunteer at NEWTON! Frequently Asked Questions Referencing NEWTON About NEWTON About Ask A Scientist Education At Argonne More Than 100%
Name: Robert
Status: student	
Age:  N/A
Location: N/A
Country: N/A
Date: N/A

I am trying to understand percentages. I understand that it is a formula such as the part/whole x 100 gives me a percent answer, but if 100% is the whole value, how can I get 300%? Is this considered the percent change from the original value or would it be better explained as three times the original value?

You raise an important issue that is flagrant in both scientific and non-scientific literature. It is absolutely necessary when expressing percentages, to specify the percentage of WHAT!! Example: If a salt doubles its solubility if the temperature is raised from 25C to 50C it is OK to say the solubility increases by 200% = 2 x 100/%, but without specifying that the basis of the percentage is the solubility at 25C., the 200% has no meaning. Unfortunately, in socially charged issues protagonists and antagonists often toss out percentages without specifying the basis of the percentage. An intentionally skewed example: "The population of the US has increased by 1000%." But what is the present population compared to -- the last census, or the estimated population in 1800? I refer you to the classic book "How to Lie with Statistics" by Darrell Huff for more subtle examples of the misuse of numbers.

Vince Calder


100% means the whole value of reference. You cannot just have 100%. You must have 100% of something, or more often 100% of an amount. Less than 100% is less than that amount. More than 100% is more than that amount. 300% of $15.00 is (300/100)*($15.00)=$45.00. You cannot receive 300% of the $15.00 from the wallet that holds that original $15.00, but you can get it from a different source. You can get it from a bet at the racetrack. Odds of 3-to-1 mean that if you win, you will get 300% of the original bet as winnings. Of course, you will also get back your original bet money.

Dr. Ken Mellendorf
Physics Instructor
Illinois Central College

Click here to return to the Mathematics Archives

NEWTON is an electronic community for Science, Math, and Computer Science K-12 Educators, sponsored and operated by Argonne National Laboratory's Educational Programs, Andrew Skipor, Ph.D., Head of Educational Programs.

For assistance with NEWTON contact a System Operator (, or at Argonne's Educational Programs

Educational Programs
Building 360
9700 S. Cass Ave.
Argonne, Illinois
60439-4845, USA
Update: June 2012
Weclome To Newton

Argonne National Laboratory