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DecayFit - Fluorescence Decay Analysis

Time-resolved fluorescence decay fit software

New and hot: One-click export of graphs and data to other applications!

Download latest version (2014.04.17):


- The compiled version requires MATLAB Compiler Runtime (MCR) version 8.3 (R2014a, Win64-bit) installed. The MCR is automatically installed with the software.

- Note that DecayFit for MATLAB does not require any MATLAB skills.

Getting started

You can use DecayFit to:

  • Analyse time-resolved fluorescence decays by iterative reconvolution or modified tailfitting.
  • Perform global optimization: Analyse multiple decays simultaneously by constraining one or more variables globally.
  • Make user defined Gaussian instrument response functions (IRFs).
  • Fit to regular exponential decays of up to four lifetimes.
  • Fit to Gaussian lifetime-distributions.
  • Perform time-resolved FRET analysis: 
    • Fit decays using a Gaussian distribution of donor-acceptor (D-A) distances.
    • Fit decays using the combination of a Gaussian D-A distribution plus an imported D-A distribution, e.g. from MD simulations corresponding to local linker dynamics.
  • Implement your own decay models (only MATLAB version).
  • Perform parameter confidence interval estimation, either via. the Jacobian matrix or by investigating the chi-square surface.
  • Perform an autocorrelation plot analysis.
  • Set shift and scatter as fit parameters; subtract background counts
- DecayFit accepts ASCII files as input and fits can be exported back to ASCII. Data can be loaded in units of ns or channels and in any vector direction. Plots can be modified and exported as high resolution figures. DecayFit can handle multiple figure windows in one session. DecayFit sessions can be saved and reopened.

- DecayFit is particularly useful when you have multiple decays and IRFs.

Feedback on the software

- Did the software open and run properly on your machine?  Yes  No
- To continue improving the software, please take the time to report bugs and suggestions back to me.

- If you have specific needs in addition to those currently provided by DecayFit contact me and I will see to implement it.

New in version 1.4 (2014.04.17)


New functionalities:
 - One-click export of figures to other applications (Ctrl+X). Supported for Windows platforms only.
 - Subtract measured background. Thanks to Mikkel Bregnhøj, Aarhus University, for the suggestion.
 - Support for negative intensity ranges.
 - Auto-checks time-scale when loading data.
 - Plot intensity on regular or log-scale.
 - Added a developers menu
 - Added direct link to bug report and requests.
 - Customize figure and graph windows.
 - Copy data points to clipboard.
 - Added recent files and recent sessions menus.

Bug fixes:
 - Fixed bug in CI calculation. Thanks to Jason B. Benedict, University of Buffalo, for reporting the bug.
 - Fixed bug when loading data with non-integer intensities.

New in version 1.3 (2013.09.10):

 - Force a data import wizard if automated import failed.
 - Merge two or more data sets (i.e. sum counts from different acquisitions).
 - Loading/saving remembers last opened/saved file.
 - Fixed bug when setting ns/channel.
 - Fixed bug in delete function.
 - The software now automatically checks for new updates.
 - Name changed from FluorFit to DecayFit to avoid confusion with FluoFit from PicoQuant.

New in version 1.2 (2013.06.27):

 - Trimmed GUI for different monitors and MATLAB versions
 - Improved loading and saving properties
 - Added a splash screen for the MATLAB version
 - Fixed a few bugs
 - Added documentation in the help menu

New in version 1.1 (2013.02.01):

 - Added two additional fitting models: 'double_exp_uncon' and 'triple_exp_uncon'. These two do not constrain the sum of pre-exponential factors to 1 in the double and triple-exponential decay models, respectively, and may adopt negative pre-factor values.

 - Now possible to plot the intensity-weighted lifetimes in the small parameter-plot window (instead of the amplitude-weighted). This plot setting is possible for the decay models: 2-4 exponentials.

 - Fixed small bug when saving/loading sessions where no extra decay plot-windows have been opened.

Previous versions:

1.3 (2013.09.10):

- The compiled version 1.3 requires MATLAB Compiler Runtime (MCR) version 7.17 (R2012a, Win64-bit) installed. Download the MCR here.


- The compiled version 1.2 requires MATLAB Compiler Runtime (MCR) version 8.0 (R2012b, Win64-bit) installed. Download the MCR here.



- The compiled versions 1.0 and 1.1 require MATLAB Compiler Runtime (MCR) version 8.0 (R2012b, Win32-bit) installed. Download the MCR here.

- Note that version 1.0-1.2 of DecayFit was entitled FluorFit at the time. This was changed from version 1.3 to avoid confusion with the FluoFit software from PicoQuant.