Error propagation and uncertainty analysis are made easy and automatic with this app that features choice of arithmetic: Traditional, Interval, Monte-Carlo, Differential, Chordals and Duals.

Lab reports are difficult enough. Now you can complete error propagation for lab reports with lower stress and in quicker time.

The CertainError Calculator app provides functions found on traditional scientific calculators but now with simultaneous error propagation at your fingertips. This app does error propagation for trigonometric, exponentials, logarithms and hyperbolic functions. The inverse functions for all of these are included too. Try doing this with any other scientific, graphing or app calculator and you will experience difficulty and wasted time. These calculators are simply not built for error analysis and it takes a lengthy procedure of steps to make them work. Every step is a chance to make a calculation mistake. The CertainError calculator provides immediate relief when you finish your first error propagation calculation with ease (see the accompanying YouTube video showing the small ‘Challenge’ problem).

There is built-in flexibility in the choice of uncertainty arithmetic. If your professor uses 'partial differentials' and 'root-mean-square (RMS),' just set the app method to 'Differentials' and the calculator will handle the uncertainty arithmetic step-by-step through each operation or function. If you work with random error, you can set the app method to 'Monte-Carlo' to activate automatic random sampling of inputs to each calculation step and then benefit from automatic statistics that express results of a 95% confidence level. The ‘Interval method’ represents the input error range with a uniform grid of points and evaluates the calculation at all combinations to generate a result set. The result-with-error is resolved using the maximum and minimum of the result set. Novel methods, 'Chordals' and 'Duals,' are based on geometric arithmetic and patent pending technology. Similar to the ‘Interval method,’ the 'Chordal method' often gives the worst-case error so you can judge if you are in trouble from error growth. The 'Duals method' uses hybrids of numbers and geometry and it is very effective at solving the 'Dependency Problem' seen in most other methods and it is robust as it can do things such as divide-by-zero-with-error without blowing up (see the screenshot example). The ‘Duals method’ often yields the smallest error as the mathematics used is superior to other methods that approximate or over-estimate error in some way.

The website provides support and education in the form of an app Help Menu (see the ? button on the app), links to YouTube Tutorials (describing error and uncertainty without math) and descriptions of Recent Projects (using either the app or software, see Industries served) in a wide range of fields such as Science&Engineering, Mathematics&Statistics, Finance, Sports and Medicine.

Ratings and Reviews

3.7 out of 5
9 Ratings

9 Ratings

EngineeringChamp03 ,

College Student

After reading about the CertainError calculator I thought I would try it because my phone’s built-in calculator could not handle my incubator temperature measurements that vary over time. This calculator app allowed me to calculate error % of the temperature controller. Using this it was easy to calculate yield and its error. In addition, I tried the Duals and Differential methods and this gave me more accurate final error measurements for some of my other experiments with compounding calculations that each have an error measurement. Would highly recommend to any college student who wants an easier and faster way to calculate errors on measurements.

IAmTopDogInLab ,

Certain about error now

I used CertainError on my lab report to get average weight and error from my lab partners. They kept texting me for the secret about how I did it with the error values the TA gave us (I will post it later once I squeeze some enjoyment out of it.) I didn’t know what to do first so I pushed ? and this was the help menu on the website. This won’t work unless your WiFi is on. Main thing is you can only edit when the yellow box is on the number and C clears what’s in the yellow box. Backspace is helpful too cause I kept making mistakes at the beginning. For me the MX button was really handy for adding up the weights.

LilacsForever82460 ,


I am so glad I found this calculator in time for my lab report. I had difficulty getting my uncertainty analysis to work. My TI-89 was no help. I didn't know which method to use but then found that I could do differential to match the examples I did from class. Saved me hours.


Ronald LaFleur
30 MB

Requires iOS 8.0 or later. Compatible with iPhone, iPad, and iPod touch.



Age Rating


  • Family Sharing

    With Family Sharing set up, up to six family members can use this app.

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