I can recommend Curve Expert;

http://www.curveexpert.net/

The free basic version is free and very easy to use. Very helpful tool!

If you have a model you could try DynaFit (http://www.biokin.com/dynafit/). It uses numerical integration and requires some effort to master its programming but examples can be copied and modified to suit. It is available without charge to university researchers.

My experience is that almost all mathematics could be done using "R" it is open source, it is command-line or script based, scalable and there are a lot of packages.....

take a look at http://cran.r-project.org/ and http://www.bioconductor.org/

R have NLS which can fit your data in any equation, challenge is how to find out best equation.

PROAST is a great bit of software designed by Wout Slob in the RIVM. The European food standards agency use it for these purposes and it is updated regularly and heavily validated. http://www.rivm.nl/en/Library/Scientific/Models/PROAST

Hi,

Here is a list of linux alternatives to Originlab which I guess is a pretty similar software to what you use:

http://alternativeto.net/software/originlab/?platform=linux

I personally didn't check all of them but I would suggest to check grace which I used in the past, at the beginning it might have a bit difficult learning curve but after it has some advantages.

They are generic fitting/plotting tools and I would guess that it is difficult to

address the "challenge is how to find out best equation". If you just need to check the RMS or CHI2 then it might be not too complicated.

In all my cases involving finding the best curve I had to code a bit.

Hope it helps.

Curve expert could be helpful: http://www.curveexpert.net/

@Fabio, Thanks for URL, it have interesting free software particularly fitxy which fite various types of shape.

@Nicolas, This URL is about commercial software, I am looking for open source or free software.

I would have serious reservations about using a tool like Tablecurve2d if you plan to make anything of the F statistic values and the like that it produces. It looks like this tool could easily lead a researcher into serious problems with overfitting. Trying out over a thousand models is certain to invalidate the resulting statistical measures of the chosen model.

Linas Balciauskas

Main problem should be not the curve fitting (there are many software packages available, and they will make fit almost any curve), but interpretation of results. If you fit polynom of 3rd, 4th order - how you interpret your finding, then?

I can recommend Curve Expert;

http://www.curveexpert.net/

The free basic version is free and very easy to use. Very helpful tool!

You can use free trial of "Eureqa" software by Nutonian (google it). It was free sometime ago, by still free 30 days trial.

I can recommend TableCurve 2D and CurveExpert Professional

I recently tried http://www.mycurvefit.com where u just copy paste your data and then you can even quickly define own equations...

http://www.mycurvefit.com

We use linear and non-linear mathematical cure fitting in intelligent power systems, especially in the parametric modelling of thermodynamic and electrical concentrated solar power systems, smart microgrid power optimization and scheduling optimization.

In our desktop experiments, we tried LabFit but found it very difficult to use. The software is unable to read data multicolumn data from csv and excel files for example.

Then learned about Datafit by Oakdale Engineering and found it much easier to use. When you use it, select "all models" in the curve fitting strategy then it ranks the solutions and polynomials in terms of best fit hierarchy options. One can then plot each to curve in a different color in overlay mode and see/judge the curve fit for each solution and parameter set.

The options for DataFit with non linear curves is however limited and we struggled for example to model simple daily energy and electrical load profile curves (used in load forecasting archetypes) with the model options available in the menus. Low price end, but good to see trial version first.

Simfit is another, free open-source option for Windows and Linux usef in simulation curve fitting with plotting. like Data-fit, the library of models allow for user-defined equations to be added to the model set.

Regards Gerro

SigmaPlot 13 now is working well. Its model library is very full and it is possible to add and edit models.

https://github.com/zunzun/pyeq2

Zun zun. I have used it's online version but now it is not working, but her is a git gepository. Ther is also Zunzun.com discussion group - Google Groups

https://groups.google.com/forum/#!forum/zunzun_dot_com

HTH

Fityk, R (glm, lm, nls, etc...)...

I should recommend qtiplot which is really handy in curve fitting (but limited in 2 coloumn data).

Check out https://terpconnect.umd.edu/~toh/spectrum/InteractivePeakFitter.htm

Data master 2003 is a  good free software for fitting  and data acquisition , allowing constrained nonlinear fitting, and user defined models with limited statistical evaluation of fits.

Origin software is one of the best for all kind of fittings, ect...... ,

http://www.lightstone.co.jp/lsieng.html

Good luck

Curve Expert is the one I use for curve-fitting. It is very straightforward and does a very good job at fitting the data. It has helped me a lot in my research. It has versions for all platforms as well. The basic suite is free.

I can recommend you ndcurvemaster:  www.ndcurvemaster.eu (for Win and Mac).for auto fitting of an unlimited number of input variables: x1, x2, x3,..., xn and their combinations: x1*x2, x1*x3, x2*x3,..., xn-1*xn

Zunzun website is active again. This is the best... However you can use the libraries in Python in your computer installing the appropriate packages in Linux...

my suggestion is to use the myassays.com

e.g. I used 4PL using the following link. The web based one is free.

https://www.myassays.com/four-parameter-logistic-curve.assay

Try AssayFit Pro, it is a free and online solution and can be used in Excel, R and python too.

http://www.assayfit.com

Curve Expert Pro for curve fitting and data analysis!! & It is a cross-platform software.

https://www.curveexpert.net/products/curveexpert-professional/

I hate sounding mercenary, but for $10 you can download my very flexible but VERY easy-to-use polynomial curve-fitting program from the website given below. PolyFit 1.1 does linear, quadratic, cubic, & exponential regression, and also does quadratic and cubic regression for TWO independent variables (i.e., a 'family' of curves). Input data are imported from EXCEL, results are tabulated and plotted and can be exported to EXCEL. 'Goodness-of-fit' parameters are calculated. SDs or CVs for the input data can also be entered.

https://www.drsimplescience.com/fitting-tool.html

I would recommend you to use curve expert free version. It works well in Mac, Windows and Linux

Let me know how it goes!

I would like to announce that I have a created and published a new free version of NdCurveMaster software for one independent variable. Please feel free to check it out, any feedback is welcome.

Click on https://www.ndcurvemaster.com and go to download, it is called NdCurveMaster 2D. It is for Mac and PC

All the best.

Tomasz

Which of the suggested apps can handle two independent variables?

I read this thread of answers to this important question! I went ahead and tried "CurveExpert Professional" from Hyams Development. I have been extremely impressed.

Extremely easy to use and it enables you to write simple equations, which are translated into the Python programming language. If you desire more complex equations this can of course be developed in the Python language.

Highly recommended and worth once off fee of $79!

Regards,

Gary

I recommend mathematica

I recommend datafit program

I recommend excel solvertool.

Is there any specific curve fitting toolbox for MATLAB functions?

Can you explain a little bit more in detail what you mean with Matlab functions? Maybe explain your problem, and then the community can help your better.

In general: The curve-fitting app in Matlab allows to use standard equations and create any kind of user-defined equations, which can be tested in example data. If the boundary conditions allow a reasonable regression, the code may be deployed to allow more automatic processing of data.

I recommend Sigmaplot12.0, it is free for one month

GeoGebra (free, multi-platform software) is dynamic mathematics software for all levels of education that brings together geometry, algebra, spreadsheets, graphing, statistics and calculus in one easy-to-use package.

Curve Fitting is supported and very easy to figure...

Euerqa is a software that creates formulas for several variables in large sets of data.

If you don´t license for specific software, I recommend use the SOLVER tool in Excel. Adicionally send you a litte example in a excel spreadsheet with a data fitting.

Did you ever used the GeoGebra Luis Morales-Salinas?

I recommend LABFIT, it is free for one month (or more) and very user friendly. This software fitted response(y) with 6 independent variables(X1, X2 and ...) and 10 adjustable parameters(maximum).

u can use this link

http://www.curveexpert.net/

For all who want to achieve some main learning goals regarding Curve fitting in a very impressive manner, check my free tool:

https://www.researchgate.net/project/CARBONARA

One of my hobbies in questions such as this is determining how long it takes for someone to recommend R. This thread got there in 2 steps. R is more a programming language than a program per se. It is sort of like recommending LaTeX for all your word processing needs. A lot of people do that too, but if you have better things to do with your time than learn programming languages, I wouldn't do either. Popular software for ordinary humans usually revolves around some version of Grace -- xmgrace, qtgrace, SciDAVis, and LabPlot.

Euerqa is the best software that can deal with any type of data. Moreover, it is based on genetic algorithms. So, I strongly recommend Eureqa for any discipline. The accuracy and complication of math forms were solved in Eureqa. NASA & other academic institutions in the U.S. are using this software since 2011.

By the way, it does not require any coding. It is easy to use.

To Saeed Alzahrani : is that software Free?

Is Eureqa available free online or not?

I want this to elaborate my data using curve fitting.....

I have installed curve-expert professional 2.6.5.... for trial...

But it give me good fitting only polynomial regression degree 14 ....

It is has no physical value.....

I need fitting model like Fourier series...

Sin or cosin, funtion which represents polarization of light.........,.

Kindly suggest me a good free online software, from where I will get best fitting and equation with coefficients as well......

@ Anton Vrdoljak: Unfortunately, you have to buy it. However, You are able to download the free trial for 30 days. I used the free trial and it produced some good equations that I needed for my research. The download link is below.

https://www.nutonian.com/products/eureqa-desktop/

Good luck!

To Saeed Alzahrani : Thank you very much for your answer.

I can recommend sigma plot.

To Sajjad Kharabati : I can bet it is great software, but it is not free...

To Sajjad Kharabati :

Now i tried to install it. But at the end i need serial number. If it available free, kindly guide me in this respect.

To: Saeed Alzahrani

I have install Euerqa. I don't understand how i can get curvefitting equation according to my data point.

I need mathematical equation cosin or sin function type according my data point curvefitting.

Have you tried non-linear least squares curve fitting - http://www.colby.edu/chemistry/PChem/scripts/lsfitpl.html

My preference is zunzun.com but that is no longer available on line

https://mycurvefit.com/

Online, free and apparently flexible in respect of functions

Armin Sepp.

It is not valid for higher data.

We will do some payment in dollars for higher values.

I have 36 values of data.

I tried this online curvefitting online version.

I need a software or online free version to get equation against my data points.

To Sidra Batool : Try GeoGebra, it is free program.

For all who want to achieve some main learning goals regarding Curve fitting in a very impressive manner, check my free tool:

https://www.researchgate.net/project/CARBONARA

I use spss

Thanks Anton vrdoljak.

I will try it

I think https://www.qtiplot.com/ is a good candidate. It is cross-platform and free. It includes useful functions for data fitting: linear, polynomial, exponential, logistic, Boltzmann, Gaussian, Lorentzian and Pseudo-Voigt.

Here is the qtiplot software for various systems:

• https://pkgs.org/search/?q=qtiplot

Hi Valerio Bellizzomi I'm using QtiPlot (0.9.8.9 svn 2288) on linux and I don't have those limitations. It is the newest version for linux and it can be installed by executing the following terminal command: sudo apt-get install qtiplot.

Here is the qtiplot software for various systems:

• https://pkgs.org/search/?q=qtiplot

I would recommend the Curve Expert.

I was looking this question, thanks

I recommend ndCurveMaster 2D - it is for free

PolyFit is also available for free. It is disgustingly simple to use and will fit linear, 2nd order, 3rd order, exponential, and 3rd order with two independent variables. You can have it for free from my website at http://alum.mit.edu/www/zamenhof

This is not a free software, but maybe, if you have matlab, its curve fitting app is a good option.

Thank you sir

If you want to try 4 different curve fit libraries, you can try out our prototype tool:

https://curvefit.tu-chemnitz.de/

Implementations in the backend are:

- Flanagan's library

- Matlab curve fit functionality from the OptimizationToolbox

- Octave Curve Fitting

and a frontend Javascript library (which - after loading the page - works also offline):

- Javascript (ml.js)

For simple fit functions all libraries work well, for more complex ones, try out yourself.

Kind regards,

Danny

You can try GraphRobot (www.graphrobot.com), a free smart web app that can fit different curves and plot the fitted curves.

Try curve expert.

An interesting free and powerful option is SCiPy1, a Python-based ecosystem of open-source software for mathematics, science, and engineering. In particular the optimization2 package. Here3 is an example for curve fitting.

1 https://scipy.org/

2 https://docs.scipy.org/doc/scipy/reference/tutorial/optimize.html#optimization-scipy-optimize

3 https://docs.scipy.org/doc/scipy/reference/tutorial/optimize.html#example-of-solving-a-fitting-problem

https://youtu.be/wWIZyxrp04I