CurveExpert Professional is a cross-platform solution for curve fitting and data analysis. Data can be modelled using a toolbox of linear regression models, nonlinear regression models, smoothing methods, or various kinds of splines. Over 90 models are built-in, but custom regression models may also be defined by the user. Full-featured publication-quality graphing capability allows thorough examination of the curve fit. The process of finding the best fit can be automated by letting CurveExpert compare your data to each model to choose the best curve. The software is designed with the purpose of generating high quality results and output while saving your time in the process.

CurveExpert Professional compares very favorably to the competition and does so at a lower price; see the interactive comparison for more information.

Major features:

• Multiplatform: runs on Windows and Linux. Saved files are portable between platforms.
• Easy-to-use User Interface: most mathematically-intensive applications are very difficult to use. CurveExpert Professional has a very intuitive interface, which allows you to import your data, generate results, and create publication-quality plots with very minimal effort. In fact, to import a file takes only four clicks, and generating a battery of results with associated graphs takes two more.
• Robust file import: data files come in many shapes and sizes, and CurveExpert Professional makes importing your data files very easy. The smart file reader avoids non-data areas of your file dynamically, and attempts to find labels for each column of data in your file.
• Publication quality graphs: an arbitrary number of graphs can be created and saved. The rendering of the plots is of publication quality, with full antialiasing support and the ability to extensively customize each graph. Graphs can be saved to a variety of graphics file formats, and they may be directly copied and pasted into another application. For the purposes of 3D plotting, scatterplots, surfaces, and contour plots are supported. Graph themes allow you to customize a look that you prefer, and reuse it. Graphs are interactive, with zooming, panning, autoscaling, and view stack capability.
• Multivariate: linear and nonlinear regressions can be computed for datasets with multiple independent variables, without any limits.
• Multicore: put your extra CPU cores to work and compute results more quickly. A typical speedup is 3.5X on a 4 core system.
• Built-in models: over 90 built-in nonlinear models, with high-quality automatic initial guesses, are available for use. The provided models cover all of the major families.
• Detailed Result Query: parameter values and uncertainties, covariance matrix, parameter histories, residual plots. Forward and backward evaluation of the model’s value, differentiation, integration, and table generation.  Residual runs test, F-Tests, Akaike's Information Criterion Test.  All results formatted beautifully in HTML reports, with fully customizable numerical formatting.
• Custom models: you can also define models yourself, using a very large library of built-in mathematical functions, and parameters in your models can take any name that you like. For more advanced users, a model can be as complex as necessary, as long as it can be expressed as a Python function. This allows the creation of extremely complicated models, instead of the normal one-line-equation models limitation in other software. Further, the number of parameters is unlimited.
• Functions: much like models, a suite of built-in functions (over 40) can be evaluated, and you can define your own custom functions as well.
• Ranking of results: results are automatically ranked by your choice of score, correlation coefficient, standard error, or coefficient of determination.
• Validated: validated against the Statistical Reference Datasets Project of the National Institute of Standards and Technology. These datasets can be downloaded directly at http://www.itl.nist.gov/div898/strd/general/dataarchive.html, but are also included verbatim in the CurveExpert distribution for you to use yourself.
• Quality spreadsheet: the built-in spreadsheet allows you to manually enter data and/or modify it with a suite of data transformation tools. Data entry and cutting and pasting capabilities are as easy as Excel.
• Localization: Importing data or interoperating in European-style environments (which use a comma as a decimal) is extremely easy; regional settings are automatically obeyed, or can be selectively enabled in order to match your particular workflow.
• Logging: a log of actions is kept across sessions of the software, in case you need to recreate a particular result. A messages pane keeps you informed of the status of every computed result.
• Documentation: Extensive documentation in HTML, PDF, and EPUB format, available both directly from the software and online at http://docs.curveexpert.net/curveexpert/pro.

CurveExpert Basic is a subset of the functionality contained in CurveExpert Professional and is intended for more casual/infrequent users.  The list below is a specific list of differences between the two; the items are listed as features that CurveExpert Pro supports, but CurveExpert Basic does not.

• Advanced models
• Functions and custom functions
• Weighting for regressions
• Linear and polynomial splines
• Polynomial regressions only supported up to 4th degree in CurveExpert Basic.
• Built-in digitizer that can be used to generate datasets from images.
• datasets with multiple independent variables are not supported in CurveExpert Basic.
• Three types of smoothers (Moving Average, Lowess, and Savitzky-Golay) that CurveExpert Basic does not include.
• Extended result detail, residuals, convergence curves, and parameter histories shown in CurveExpert Pro.
• Ability to evaluate points on the resulting curve fit, differentiate, integrate, and compute arclength is included in CurveExpert Pro.
• In CurveExpert Pro, new plots can be created and customized with any results placed upon them; in CurveExpert basic, there is one plot per result.
• Comparing two regressions is not supported in Basic
• Multiple cores when computing large sets of results; CurveExpert Basic does not.
• User customizable plug-ins
• User customizable graph themes
• 3D visualization
• graphing: annotations and addition of shapes and images not supported in CurveExpert Basic.
• Hot linking (tracking of data file updates) not supported in CurveExpert Basic.

I'm really impressed by the enhanced options of CurveExpert Professional, streamlined to give the professional the most quick answer to detect dependencies within its data, express them via formulas, and even calculate with them immediately. Definitively there isn't anything better on the market!

--Ralf Fritzsch, Federal Waterways Research Institute, Hamburg, Germany

CurveExpert Basic was indispensable in my long and arduous search for an equation to fit highly curved, serpentine data. With a certain amount of trial and error I ultimately found a solution – a combination of sine terms, arctangent terms, and a fourth-order polynomial – but I needed 19 parameters to make it fit. CurveExpert was the only curve fit program which I found that would work. Not only did CurveExpert allow enough parameters but it fit the curve to the data exceedingly well – in fact I would call it a perfect fit.

I find that Curve Expert Professional is more versatile and much easier to use than CurveExpert Basic, for example, when entering the initial guesses for the parameters. The graphics of CurveExpert Professional are far superior, as well.

--M. Nealon

As an Embedded Software Engineer who is involved with the control of medical devices, the ability to quickly determine the underlying relationship of easily-gathered empirical data is quite an advantage. CurveExpert has proven to be an invaluable tool when used in this respect and has saved countless hours of unnecessary effort. The information gained through CurveExpert is easily applied to process analysis, simulation and control purposes. CurveExpert's publication grade data plots make presentation and development documentation quite simple. The software is a real joy to use and the affordable price means this software has been created to be utilized by a wide range of end users from student to professional.

--S. Nickerson, Sr. Software Design Engineer

CurveExpert has been a wonderful go-to application when I need to fit data very quickly.  In some cases, I’ve developed and implemented a simple model in five minutes, and I could never do that with most other software.  Just copy and paste in the data points, hit “CurveFinder,” watch it crank through the models automatically, then grab the best one and go.  The models all provide the formulas and coefficients needed to use them in something simple, such as a spreadsheet.  I find especially useful the Sigmoidal family of models for a lot of my call center data.  I highly recommend this software to anyone wanting to quickly understand the relationship between two variables.

--TJM

I use CurveExpert Professional infrequently but it is nice having that extra tool in your bag when you need it; especially when CurveExpert works easily, accurately and as automatically or manually as you choose. My application is sensors attached to complex SCADA systems where precision calibration of measurement data is required. A vendor will provide calibration data and a curve fit which rarely match. I use CurveExpert to resolve the disconnects. I do not use the majority of CurveExpert's capability but for the past 15 years CurveExpert has completely solved my sensor calibration problems. And the customer service CurveExpert provides is second to none.

-- Michael C Maguire, Senior RF Systems Engineer, Consultant (formerly of SpaceX)

We use CurveExpert [Basic] extensively in our research on probability distributions of forest fires. As an exploratory and analytical tool it is unparalleled in its flexibility, ease of use, and accuracy.

--Don Falk, Associate Professor, University of Arizona

I have used CurveExpert [Basic] to fit some Temperature vs Time dehydration food data to give me a grounding for the basic fitting function to be used. One can then modify the basic fitting function accordingly to give meaning to the fit parameters calculated by curve expert.  I especially find useful the automatic fit function.

--Rabindranath Ramsaroop, Trinidad. West Indies.

I have used CurveExpert Basic for years and it is one of the most indispensible applications in my arsenal. CurveFinder is one of the most useful features in CurveExpert Basic and I will likely lean on it heavily in CurveExpert Professional. Does most of the hard work for you in coming up with the "best" curve fit.

I have just started to explore CurveExpert Professional and as I expected I am definitely going to upgrade. The new graph interface is very nice. A lot to work with there to get really high quality plots. The ability to use a subset of TeX is awesome. I use MathType from Design Science in Office documents so having TeX in CurveExpert Professional plots is a real plus for documentation.

The help file appears quite well done and not just an afterthought. The ability to directly download a PDF version from the help file is nice.

--Larry Zipper

In project design engineering, and other engineering activities as well, the evaluation of the physical phenomenon is greatly improved supported in the program, which allows the visualization of the behavior of the variables involved.

The program is amazingly smart and well architected. Involves the mathematical components that participate in functions and its physical setting.

I appreciate your dedication, intelligence and accuracy in the preparation of this valuable tool.

Mainly for the unpretentious simplicity as you released your creation to the scientific and engineering field.

--Iwan Sabatella, Correcta Engineering, Curitiba - Brasil