Current Version: 5.0 (Released: 08/08/2014)


QtFuzzyLite 5 is an entirely new Qt-based graphic user interface for fuzzylite. Its goal is to significantly speed up the design process of your fuzzy logic controllers, while providing a very useful, functional and beautiful graphic user interface that allows you to easily design and directly interact with your fuzzy logic controllers in real time.

QtFuzzyLite 5 was re-built from the ground up to provide a beautiful interface, a better experience, and lots of relevant information that reveal intimate details of your fuzzy logic controllers.

QtFuzzyLite 5 is the perfect companion for teaching fuzzy logic control, and the best application today to design fuzzy logic controllers with the most complete set of features. Furthermore, with a new and different perspective, QtFuzzyLite 5 encourages the new generation of scientists and engineers to rethink fuzzy logic control and seriously consider the wonderful set of new opportunities and features that fuzzylite will add to your applications, not to mention that you will be truly incorporating Artificial Intelligence into your applications.

Please, notice that, QtFuzzyLite 5 is now a commercial and closed-source application for the sole purpose of raising funds to continue the development of the fuzzylite family of products, all of which will always remain free and open source.

… there are still many things to do!!!

To buy a license, please click below. After your purchase, you will automatically receive an email with your FuzzyLite License Key.

Please, read the End User License Agreement (EULA) before purchasing a license.
Your purchase is an implied agreement that you accept the conditions expressed in the EULA.

In addition, you can also contribute with a donation that I will spend on the product of your choice.

NZ$49.99 NZ

QtFuzzyLite Single License
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  • All the features and improvements of fuzzylite v5.x.
  • Significantly improved graphic user interface.
  • New graphic views: Ordinal and Singleton, both provide more information for every controller, especially Mamdani and Takagi-Sugeno
  • Design your controllers with multiple rule blocks.
  • Benchmark your fuzzy logic controllers.
  • A click away from exporting every component to the FuzzyLite Language fll.
  • Manually sort terms within a variable, or automatically according to the centroids.
  • Show predefined templates when importing controllers.
  • Completely redesigned Term Editor.
  • Better options for cloning of terms: Manual, Range, Symmetric, Next Term.
  • Live editing of Rules, and Discrete and Function terms.
  • Tooltips showing coordinates, and Vertical and Horizontal guides.
  • Surface 2D
  • Type of Engine and the inference reasons.
  • New terms: Concave, Cosine and Spike.
  • Visualize \(\tilde{y}\) or \(\mu(y)\) in Output Variables.
  • Redesigned FldExporter that allows: exporting a specific number of results over the variables range, export from a custom FuzzyLite Dataset, and save results to files. Plus, export headers, input values and output values.
  • Option to export to C++ without using the namespaces.
  • QtFuzzyLite.ini to customize many aspects such as number of decimals, look and feel, confirm quit, resolution of defuzzifiers, window geometry, graphics resolutions, show templates of importing.
  • Improved check for updates.
  • Natural support for NaN and Inf values in components.
  • A lot more visual information.
  • More beautiful graphics.
  • … and many more!


QtFuzzyLite v5.0 in Windows XP (Cleanlooks L&F)

QtFuzzyLite v5.0 in Windows XP (Cleanlooks L&F)

QtFuzzyLite v5.0 in Ubuntu Linux (Cleanlooks L&F)

QtFuzzyLite v5.0 in Ubuntu Linux (Cleanlooks L&F)

QtFuzzyLite v5.0 in Mac OS X (Snow Leopard)

QtFuzzyLite v5.0 in Mac OS X (Snow Leopard)


tutorial on fuzzylite
tutorial on qtfuzzylite

End User License Agreement


This SOFTWARE PRODUCT is protected by copyright laws and international
copyright treaties, as well as other intellectual property laws and
treaties. This SOFTWARE PRODUCT is licensed, not sold.

End User License Agreement

This End User License Agreement ("EULA") is a legal agreement between you
(either an individual or a single entity) and FuzzyLite Limited with regard
to the copyrighted Software (herein referred to as "SOFTWARE PRODUCT" or
"SOFTWARE") provided with this EULA. The SOFTWARE PRODUCT includes computer
software, the associated media, any printed materials, and any "online" or
electronic documentation. Use of any software and related documentation
("Software") provided to you by FuzzyLite Limited in whatever form or media,
will constitute your acceptance of these terms, unless separate terms are
provided by the software supplier, in which case certain additional or
different terms may apply. If you do not agree with the terms of this EULA,
do not download, install, copy or use the Software. By installing, copying
or otherwise using the SOFTWARE PRODUCT, you agree to be bound by the terms
of this EULA. If you do not agree to the terms of this EULA, FuzzyLite
Limited is unwilling to license the SOFTWARE PRODUCT to you.

  1. Eligible Licensees. This Software is available for license solely to
    SOFTWARE owners, with no right of duplication or further distribution,
    licensing, or sub-licensing. IF YOU DO NOT OWN THE SOFTWARE, THEN DO NOT

  2. License Grant. FuzzyLite Limited grants to you a personal,
    non-transferable and non-exclusive right to use the copy of the Software
    provided with this EULA. You agree you will not copy the Software except as
    necessary to use it on a single computer. You agree that you may not copy
    the written materials accompanying the Software. Modifying, translating,
    renting, copying, transferring or assigning all or part of the Software, or
    any rights granted hereunder, to any other persons and removing any
    proprietary notices, labels or marks from the Software is strictly
    prohibited. Furthermore, you hereby agree not to create derivative works
    based on the Software. You may not transfer this Software.

  3. Copyright. The Software is licensed, not sold. You acknowledge that no
    title to the intellectual property in the Software is transferred to you.
    You further acknowledge that title and full ownership rights to the Software
    will remain the exclusive property of FuzzyLite Limited, and you will not
    acquire any rights to the Software, except as expressly set forth above. All
    copies of the Software will contain the same proprietary notices as
    contained in or on the Software. All title and copyrights in and to the
    SOFTWARE PRODUCT (including but not limited to any images, photographs,
    animations, video, audio, music, text and "applets," incorporated into the
    SOFTWARE PRODUCT), the accompanying printed materials, and any copies of the
    SOFTWARE PRODUCT, are owned by FuzzyLite Limited. The SOFTWARE PRODUCT is
    protected by copyright laws and international treaty provisions. You may not
    copy the printed materials accompanying the SOFTWARE PRODUCT.

  4. Reverse Engineering. You agree that you will not attempt, and if you are
    a corporation, you will use your best efforts to prevent your employees and
    contractors from attempting to reverse compile, modify, translate or
    disassemble the Software in whole or in part. Any failure to comply with the
    above or any other terms and conditions contained herein will result in the
    automatic termination of this license and the reversion of the rights
    granted hereunder to FuzzyLite Limited.

  5. Disclaimer of Warranty. The Software is provided "AS IS" without warranty
    of any kind. FuzzyLite Limited disclaims and makes no express or implied
    warranties and specifically disclaims the warranties of merchantability,
    fitness for a particular purpose and non-infringement of third-party rights.
    The entire risk as to the quality and performance of the Software is with
    you. FuzzyLite Limited does not warrant that the functions contained in the
    Software will meet your requirements or that the operation of the Software
    will be uninterrupted or error-free. FuzzyLite Limited IS NOT OBLIGATED TO

  6. Limitation of Liability. FuzzyLite Limited's entire liability and your
    exclusive remedy under this EULA shall not exceed the price paid for the
    Software, if any. In no event shall FuzzyLite Limited be liable to you for
    any consequential, special, incidental or indirect damages of any kind
    arising out of the use or inability to use the software, even if FuzzyLite
    Limited has been advised of the possibility of such damages, or any claim by
    a third party.

  7. Rental. You may not loan, rent, or lease the SOFTWARE.

  8. Upgrades. If the SOFTWARE is an upgrade from an earlier release or
    previously released version, you now may use that upgraded product only in
    accordance with this EULA. If the SOFTWARE PRODUCT is an upgrade of a
    software program which you licensed as a single product, the SOFTWARE
    PRODUCT may be used only as part of that single product package and may not
    be separated for use on more than one computer.

  9. OEM Product Support. Product support for the SOFTWARE PRODUCT is provided
    publicly by FuzzyLite Limited or other users via the forums available at For private support, you may contact
    FuzzyLite Limited, but beware that additional costs will apply.

  10. No Liability for Consequential Damages. In no event shall FuzzyLite
    Limited be liable for any damages whatsoever (including, without limitation,
    incidental, direct, indirect special and consequential damages, damages for
    loss of business profits, business interruption, loss of business
    information, or other pecuniary loss) arising out of the use or inability to
    use this SOFTWARE PRODUCT, even if FuzzyLite Limited has been advised of the
    possibility of such damages. Because some states/countries do not allow the
    exclusion or limitation of liability for consequential or incidental
    damages, the above limitation may not apply to you.

  11. Indemnification By You. If you distribute the Software in violation of
    this Agreement, you agree to indemnify, hold harmless and defend FuzzyLite
    Limited from and against any claims or lawsuits, including attorney's fees
    that arise or result from the use or distribution of the Software in
    violation of this Agreement.