Science, Tech, Math › Science How to Calculate Experimental Error in Chemistry Print scanrail / Getty Images Science Chemistry Basics Chemical Laws Molecules Periodic Table Projects & Experiments Scientific Method Biochemistry Physical Chemistry Medical Chemistry Chemistry In Everyday Life Famous Chemists Activities for Kids Abbreviations & Acronyms Biology Physics Geology Astronomy Weather & Climate By Anne Marie Helmenstine, Ph.D. Anne Marie Helmenstine, Ph.D. Chemistry Expert Ph.D., Biomedical Sciences, University of Tennessee at Knoxville B.A., Physics and Mathematics, Hastings College Dr. Helmenstine holds a Ph.D. in biomedical sciences and is a science writer, educator, and consultant. She has taught science courses at the high school, college, and graduate levels. Learn about our Editorial Process Updated on September 08, 2019 Error is a measure of accuracy of the values in your experiment. It is important to be able to calculate experimental error, but there is more than one way to calculate and express it. Here are the most common ways to calculate experimental error: Error Formula In general, error is the difference between an accepted or theoretical value and an experimental value. Error = Experimental Value - Known Value Read More How to Calculate Percent Error By Anne Marie Helmenstine, Ph.D. Relative Error Formula Relative Error = Error / Known Value Percent Error Formula % Error = Relative Error x 100% Example Error Calculations Let's say a researcher measures the mass of a sample to be 5.51 grams. The actual mass of the sample is known to be 5.80 grams. Calculate the error of the measurement. Experimental Value = 5.51 gramsKnown Value = 5.80 grams Error = Experimental Value - Known ValueError = 5.51 g - 5.80 gramsError = - 0.29 grams Relative Error = Error / Known ValueRelative Error = - 0.29 g / 5.80 gramsRelative Error = - 0.050 % Error = Relative Error x 100%% Error = - 0.050 x 100%% Error = - 5.0% Cite this Article Format mla apa chicago Your Citation Helmenstine, Anne Marie, Ph.D. "How to Calculate Experimental Error in Chemistry." ThoughtCo, Aug. 28, 2020, thoughtco.com/how-to-calculate-experimental-error-606086. Helmenstine, Anne Marie, Ph.D. (2020, August 28). How to Calculate Experimental Error in Chemistry. Retrieved from https://www.thoughtco.com/how-to-calculate-experimental-error-606086 Helmenstine, Anne Marie, Ph.D. "How to Calculate Experimental Error in Chemistry." ThoughtCo. https://www.thoughtco.com/how-to-calculate-experimental-error-606086 (accessed April 28, 2024). copy citation