Software - FWI Calc

Current Stable Version: BETA (15th April 2023)



FWI Calc is a small Windows® 32 bit platform application that allows Fire Danger Indices (FWI + 15 other indices) to be calculated from data obtained from personal weather stations (a small data file that most weather station software is capable of producing is parsed by FWI Calc once a day). It is Freeware.

Important Notes

  • Use the MSI Installation File for new installs, or to upgrade FWICalc if it was previously installed using an MSI file. During the install procedure make sure it is installing to the same folder as your current FWI.exe resides. You may be able to change the installation location during installation, however this may require you to run the MSI file with administrator rights.

    For FWICalc installations that were previously "manually installed" please copy the 5 necessary files from the manual installation notes below to the correct FWICalc folder, overwriting existing files; stop FWICalc running (File / Exit) before doing so.
  • PLEASE NOTE: There has been a very long break (3 years) between updated versions. Its author will attempt to release updated versions from time to time, though users should not expect the software to be fully supported. Errors encountered or improvement ideas can be forwarded to
  • MicroSoft continues to upgrade its security system on All operating systems from Windows 7 - Windows 11. This may prevent the Help File (fwicalc.chm) opening correctly. Use Windows Explorer or My Computer to go to the Help Folder where you installed FWICalc. Right-click on the fwicalc.chm file, select Properties. You should see an unblock button near the bottom of this dialog - click it - the file should now work. Failing this - a PDF (1.16MB) version is now supplied as part of the install. It is also available Here.

What's New...

  • Added FTP encryption type selection (None , Tls, Ssl). Upgraded application to utilise OpenSSL-3 (Builds 118+ require two replacement DLL files .. libcrypto-3.dll & libssl-3.dll).
  • Repaired an error in the Weather Forecast retrieval system affecting European users.
  • Repaired an error in this website code preventing some European users uploading their fire weather indexes to this site.
  • This is a development version, meaning there are some additional functions enabled that assist with fault tracing in the application, they do not affect the overall functionality of the application.

Free Downloads...

This is Freeware, it comes with no warranty or user guarantee, however I do guarantee it is virus/spyware free if uploaded from this site...

THE WINDOWS INSTALLER (MSI) MAY ASK YOU TO REMOVE THE PREVIOUS VERSION BEFORE INSTALLING THIS LATEST PACKAGE (All your data files and settings will be preserved) - Go to Start Menu / Settings / Apps - Click on FWI CALCULATOR - Click on Uninstall.

Operating System        Download        
©Windows 7/8/10/11 (32 or 64bit) (Stable Version BETA)

FWI Calculator has not been specifically written for these operating systems, however the current version does appear to operate without error.

WINDOWS 64 Bit Systems: FWI Calculator may not function on some 64 bit operating systems (no fixes are available)! It is suggested to install FWI Calculator to the "Program Files (x86)" folder (eg. C:\Program Files (x86)\FWI), this is the default in the installer. This should allow the program to run with 32 bit emulation. Failing this try installing in its own separate folder (eg. C:\FWI).
32 bit Windows Installer Package (8.42Mb fwi_calc118.msi)
©Windows 95, 98, 2000, XP, VistaNot Available
©Apple Mac or LinuxNot Available
(For use with Current Version BETA Only!)
You MUST DOWNLOAD ALL 5 FILES! The FWI.exe file, and the four DLL files need to be installed to avoid any compatibility issues, these need to be placed in the main folder (eg. Program Files (x86)/FWI) where you installed FWICalc. The two additional Help Files (fwicalc.chm & fwicalc.pdf) should be placed in the help folder (eg. Program Files (x86)/FWI/help).

NOTE: If you are copying into the "Program Files" or "Program Files (x86)" folders, make sure you have FULL ADMINISTRATOR PRIVELEGES otherwise the files could be written to a "VirtualStore" folder under your User Name!
Application Files
FWI.exe (5.32MB)
fwimath.dll (433KB)
fwidat.dll (1.34MB)
libcrypto-3.dll (3.31MB)
libssl-3.dll (788KB)

Help Files
fwicalc.chm (801KB)
fwicalc.pdf (1.32MB)

The Windows Installer Package will guide you through the setup process.

Help AvailableClick Here to download a PDF (1.31MB) version of the Help File for FWICalc.

Weather Software Web Tag File Downloads...

Note: These files have not been tested on all systems; the "Date Tag" may still cause issues on some systems. FWICalc is looking for mm/dd/yy or dd/mm/yy depending on your countries date format (Year can be 4 digit. Separators can be / or - or .). Some weather software provides individual Day, Month and Year tags so you could create a date tag that consistently works eg. Cumulus: <#month>/<#day>/<#year>.

Click on the links below to download...
24 Hour Rainfall Used (Semi-Colon delimiter)
Weather SoftwareDownload
Weather Displaywd24_input_values.txt
Cumulus (1.9.1+)cu24_input_values.txt
Wetterstation (de)ws24_input_values.txt
Annual Rainfall Used (Semi-Colon delimiter)
Weather SoftwareDownload
WeatherLink (Davis)wl_input_values.htx
Weather Displaywd_input_values.txt
Wetterstation (de)ws_input_values.txt
Example HTX file containing all Web Tags
(to be used as "Input File" for web parsing)
Example Web Input Filefwi1.htx (right click to save)
fwi1.html (parsed file)

Live Example (web outputs for Arthur's Pass)...

Wind Speed
CBICBI DCAngstromAngstrom DCFMIMax Temp
Low Humid
Max Wind
Forecast weather data provided by
F 23/05/20248.07712.00.0066.3261.020.3LW2.2LM0.0LM50LW0VH3645LW00.5LW5.8LW27.38.0
F 22/05/20246.08410.00.0055.5140.510.1LW1.7LM0.0LM50LW0HI1337LW0-1.0LW6.3LW29.56.0
F 21/05/20248.08411.00.0045.3140.110.0LW2.3LM0.0LM60LW0MD123LW0-0.9LW6.1LW29.08.0
F 20/05/202410.0844.00.0030.9130.010.0LW1.0LM0.0LM70LW0LW0LW0-0.6LW5.8LW28.311.0
(15:30hrs) BETA (15-04-2023)

Upgraded application to utilise OpenSSL-3 (This build requires two new DLL files .. libcrypto-3.dll & libssl-3.dll, the previous version 1 crypto files are now redundant) BETA (15-04-2023)

Added FTP encryption type selection (None , Tls, Ssl). A quick fix! BETA (27-03-2023)

Some bugs fixed. Repaired faulty FWI Forecast function for European users. BETA (15-12-2020)

Added predictive 4-5 day fire weather via weather forecasts (requires setup of free account). BETA (25-05-2020)

Fixed an error that was introduced into the BKDI calculation in the previous version, this used a temperature of zero degrees instead of the maximum in the 24 hour period.

v11.3.(1-9).113 BETA (21-04-2020)

Changed some of the statistics and webtags. Changed the format of the main FWI data file to give it more flexibility (it is backed up). You will need to choose your Front Page Chart Titles again (FWI Setup / Application Settings), and HTML Table Setup column headings (Internet / Web/File options). Allowed WX Stn units for humidity to allow for RH Decimal; they are still stored as RH % however. As this is a BETA changes have been made on the fly (Minor Version 1-9). To get the latest edition of the BETA overwrite your application files with the files in the CORRUPTED FILE section (ALL EXE & DLL files required), or use the MSI Install File to upgrade from lower versions (it will remove earlier versions only if originally installed with this technique).

v11.2.1.112 (05-04-2020)

A small data file can be created that POSTS automatically to the FWICalc website (see Application Settings in FWI Setup to enable); requires an internet connection. The data can be viewed in maps or tabular form from within the website. Some further exception handling routines invoked to try and protect against crashes. All data/configuration files are now written to the ProgramData folder (originally written to a virtual location from Windows Vista+); at first startup any original files are copied across, and the application is pointed at these new files.

v11.1.2.111 (18-03-2020)

Enabled "Check for Updates" from within application. This will take you to this webpage if an update is available. You must download the 32 bit Windows Installer Package (8.42Mb fwi_calc118.msi) to upgrade. Repaired the Fireboard so toggling the Danger Text from Uppercase to Title Case now functions. Enhanced the applications error logging procedure so its more useful to the programmer. Other minor changes to prevent errors being raised needlessly. Windows 10 compatibility tweaked.

v11.1.1.110 (14-03-2020)

Allowed ssl (https) input files to be used. Two new dll files must be in the root directory of FWICalc.

v10.5.2.109 (27-03-2017)

Included a Windows version sensor, and tests for Windows 10 compatibility during setup.

v10.5.1.108 (21-03-2017)

Changed code that reads data input file to do some further cleaning of spaces and line-feeds to assist MeteoHub users.

v10.4.1.107 (11-05-2016)

Six critical data files can now be automatically backed up. Go to FWI Setup/Application Settings to select location to save.

v10.3.1.106 (24-02-2016)

Some minor changes required for Windows 10 compatibility.

v10.2.1.105 BETA (13-06-2015)

Minor changes required to previous BETA.

v10.0.0.104 BETA (31-10-2014)

Enhanced Fireboard adjustments. Allowed user to define danger thresholds for Angstrom, GFDI and FFDI indexes. This build will be reissued as Build 105 once it passes muster.

v10.0.0.104 (16-10-2014)

Some minor fixes and improvements.

v9.9.1.97 - (1-06-2013)

Changes to way BKDI is calculated (modified Crane 1982 algorithm). Created Email Alarm system. FWICalc can now read weather data file every 15 minutes and use peak daily values in FFDI, GFDI and optionally in CBI, FMI and Angstyrom indexes. Have changed BKDI index so it now stores as a fractional number (displays as integer however), this creates more accurate calculations and conversions.

v8.8.1.96 (21-02-2013)

Repaired some bugs pointed out.

v8.7.3.95 (07-02-2013)

BKDI now displays and accepts values as per your units rainfall setting (mm/in). Metric range 0-203, Imperial range 0-800. If you have version and wish to upgrade prior to next automatic release upload FWI.exe from the Corrupted Files section and overwrite this existing file in your FWICalc installation folder.

v8.7.2.92-94 (05-02-2013)

Added FFDI, GFDI, BKDI & DF indexes. Revamped main window user interface. Build 93 removes a bug notified when FWICalc is minimised to taskbar and automatic calculations proceed (Cannot focus non-visible window), also includes a Fuel Load Estimator for those folk that asked.

v8.3-6.0.86-91 (BETA 20-01-2013++ Not released)

Moved FWI Math and some Data File functions to DLL (Dynamic Link Library). This reduces some memory usage, and allows the FWI Math functions to be exported to other software. Fireboard now shows indice used and it's value, and title will auto-size. Cure Table can now suggest values based on hemisphere. Minor changes to Setup Page to force correct value entry.

v8.2.0.85 (30-12-2012)

Very minor upgrade to remove some redundant code, and fix my spelling errors. Don't worry if auto-updater is not asking you to upgrade to this version. If you really want it - upload FWI.exe from the "CORRUPTED FILES" upload section and place it in the main FWICalc folder.

v8.1.0.84 (26-12-2012)

Complete revamp of database file format. New fire indexes (Angstrom, FMI) and calculation of Australian Code Red index (from FWI). Fireboard now allows for 6 segment Code Red board, with segment colours selectable via the colour scheme dialog (ie. FWI, FWI Code Red, CBI & Angstrom). Main page window now allows for selection of shown indexes (date is still compulsory). ^fwitable^ now allows for selection and order of indexes plus more flexibility in formatting. Print routine also allows for selection and order of indexes. Multiple new webtags available.

v7.6.1. Builds 81 - 83 (01-12-2012)

All BETA releases with tweaking of ^fwitable^ Webtag format.

v7.6.0.80 (03-11-2012)

Incorporated 2D Fireboard graphic. Minor changes to Import/Export functions. Minor fixes.

v7.5.0.79 (06-08-2012)

Redesigned Import/Export feature to make it less memory intensive when used with large input files. Changed FTP Server setup procedure to prevent log-in failures with some servers. Extended FTP log to provide more detail information. Found solution to errors caused by VWS data files not localising list or decimal separators (data.csv). Other minor changes.

v7.4.0.78 (26-05-2012)

Windspeed units/input can now be m/sec or ft/sec. Both VWS & Cumulus data files can now be directly imported into FWICalc. Numerous other adaptions and changes to take advantage of the new compiler functions.

v7.3.0.77 (27-02-2012)

Completely transferred application production to new compiler language. This version never released as always in TEST BETA.

v7.2.0.76 (14-01-2012)

Restart Button now inserts all missed days at end of FWI Data File with Fudge values. Information Dialog now available that shows information / statistics of FWI Data File. FDC values (FFDC,SFDC,GFDC) have options in both the Application Settings and Web File Setup to be shown as kW/m². PS. This is the last of Holiday Season updates - Cheers!

v7.1.3.75 (07-01-2012)

Included CSV File Import function. Repaired bug that disallowed negative temperatures on some operating systems. Removed a few caution screens that were no longer required.

v7.1.2.74 (5-01-2012)

Interim Update: Provided CSV Export function. Repaired time fault reported on some Windows 7 platforms. Changed editing technique to double-click on data grid. Fixed minor issues reported by users.

v7.01.73 (12-10-2011)

Maintenance update. Fixed minor issues reported by users.

v7.00.72 (10-06-2011)

Forest type selection is now available in setup; this will make FFDC more accurate in specific environments. Forest Type, last GFDC,SFDC & FFDC kilowatt intensities are now available in webtags. Will make them available in web table in next release. Fixed bug in DMC winter calculation.

v6.18.71 (28-05-2011)

A FWICalc Restart button has been added to front-page to assist in getting it going again after data has stopped being processed (to be used if you don't want to put missed day data in manually).

v6.17.70 (14-05-2011)

Fixed an issue with the calculation of the monthly CBI value, and modified Graphing Package to make 3D graphs more robust. Numerous WebTags added for current year highs/lows.

v6.16.69 (3-05-2011)

Fixed error in FTP component causing freeze up if broadband connection fails during transfers. HTML Table Column headings can now be edited by the user & up to 100 rows of data permitted. Further WebTags added.

v6.15.68 (7-01-2011)

Activated automatic update function in Help menu (Check for Updates). This will automatically upload & install FWI Calculator components.

v6.14.67 (6-01-2011)

Included setup function to account for winter ground snow at weather station. Also modified HTML Table function to allow for full expansion of table headings. Fixed some minor bugs in the Environment variable setup routine (scrub must have a height > 0).

v6.13.66 (14-10-2010)

Corrected error that prevented temperature appearing in some webtags.

v6.12.65 (22-09-2010)

File fwiweb.xml is now created irrespective of File Settings so it can uploaded using 3rd party FTP software.

v6.11.64 (12-08-2010)

Corrected bug that prevented decimal separator (as comma) on some machines. Introduced more HTML web tags. Help is now available online as website or PDF file.

v6.10.63 (1-08-2010)

Fixed error in CBI recalculation routines (only effected imperial temperature inputs).

v6.00.62 (4-07-2010)

More issues with Windows 7 implementation patched, these have caused issues with RAS (Dialup modem) connection issues on all operating platforms. Users may need to reapply their RAS settings.

v6.00.61 (21-06-2010)

A problem associated with Windows 7 & some 64bit systems has been creating a "Previous day data not found!" error has been reported by some users - this patch should (hopefully) resolve this.

BETA v6.00.60 (10-06-2010)

Revamped the FWI Setup process (hopefully more intuitive, and self checking). Removed some memory overhead, and fixed some reported bugs.

v5.23.58 + 59 (31-05-2010)

Application is now portable; more than one instance is allowed (from differing folders only) so multiple weather stations can have FWI data processed. Repaired 32bit installer error.

v5.22.57 (24-05-2010)

Removed some minor bugs. Added ^parsetime^ as a new miscellaneous web tag. Changed old 16 bit installer for 32 bit MSI Windows Installer.

v5.22.56 (05-12-2009)

Introduced HTML Help for Windows 98, XP, Vista Users. FTP Log, and Minimise to System Tray now available on start up.

v5.21.55 (29-11-2009)

Can now upload a preformatted XML file to your website, that in turn can be uplifted by this website and utilised in Google Mapping services etc. This version had an introduced problem of "double parsing" weather files.

v5.1.54 (05-11-2009)

Revamped the database to future-proof it (please note that all databases are modified in the installation process - your original data is preserved in file - default53_bak.fwi). Added further facilities in graphing package, GIF images can now be saved with a transparent background.

v5.0.53 (1-11-2009)

Fixed notified bugs (CBI Danger Code & Graph Recall Button Error).

v5.0.52 (29-10-2009)

Entirely replaced graphing package, can now create & FTP graphs to server. Fixed the "Exit" bug! Revised entire program so it should run on Vista.

BETA v5.0.51 (25-10-2009)

Chandler Burning Index now calculated, new graphing package, new Internet / FTP system, new HTML parse tags, fixed bugs.

v4.1.50 (14-06-2007)

Included method of changing Fire Danger Rating colors (Edit/Fire Danger Color Scheme).

v4.1.49 (04-05-2007)

Broadband connection now selectable in RAS/FTP setup dialog.

v4.1.48 (15-04-2007)

Fixed bug effecting HTML table units displayed.

v4.1.47 (05-03-2007)

Fixed some user identified bugs. Enabled the "GRASS CURE TABLE" feature.

v4.1.46 (23-05-2006)

Found a memory leak that needed patching, also reduced the CPU load during processing functions. Removed some redundant buttons. Added the "FUDGE" feature, allows data to continue be written to the data file even if the wx stn software has crashed and stopped creating input files.

v4.1.45 (19-05-2006)

Just some subtle improvements to the graphing package - can now change the colour of most graph elements, can now swap which series is shown in front (handy on area graphs), changed the graph print routine so you can choose printer & print properties, you can now show a red band on the graph which indicates high-extreme fire danger for the chosen indice.

v4.1.44 (17-05-2006)

Wouldn't you know it as soon as I release the new version someone points out a bug. The ActiveX bug in the installer program has been remedied (I hope). I have allowed for selectable delimiting characters in the Weather station input files (default is Line Feed).

v4.1.43 (16-05-2006)

YES there has been a huge gap in the development time. That is because a cooked PC and corrupted backups meant I lost the original source code for the project. I have now rewritten, and reverse engineered the 37,000 lines of code used to create this application. It may look the same, but builds 1..42 have seen a dramatic change in the way it handles the algorithms and other routines. RAS & FTP procedures have been completely rehashed (made more simple I hope), multiple bugs fixed, unit of measurement selection added, hemisphere & country selection added, latitude & longitude now effect some indices, print feature is now enabled, the graphing package has been rewritten, plus a few other tweaks.

v4.0 (16-04-03)

Added "Start Minimised" checkbox on main entry form. This permits the application to start "off screen" which is useful if it is part of a series of applications running automatically on the host PC (such as in an automatic weather station situation).

v3.9 (31-03-03)

Added "Process Now" button to Web Options page to allow forcing of Data File processing irrespective of data already existing (use with caution). Moved "Parse Now" button on Web Options page, and limited function to only parsing files. Data File is no longer processed.

v3.8 (28-03-03)

Added 43 new statistical tags to the parse file tag list (^sta...^).

v3.5 to v3.7 (05-01-03) (Don't ask)

Allowed for extra file in Parse file routine (now x4), but now very extendable. Added Last Fire Danger Rating colour tags to parse file tag list for FF, SF & GF. Streamlined save routines and extended capability of setup routines. Added "Apply" buttons to Web Options & Graph pages to enable changes without leaving page. Sorted out Environment Set/Use default value system. Added "New" to file menu, and rehashed method of file creation.

v3.4 (02-01-03)

Corrected flaw in Display menu "year" routine. Fully automated builtin version updater for versions 3.1+. Slight changes to way display updates itself (no more added blank lines).

v3.3 (23-12-02)

Corrected occassional errors on selecting data in grid. Address data file directly for ALL values now. Save on change now automatic. Changed graphing routine so date range or last record count can be used (limit 100 records displayed). Changed web tags slightly. Only major change ^fwitoday^ becomes ^fwifwi^. This was because "todays" records may not be available at time of parsing so "last" record is displayed instead. Added "Parse Now" button on Web/Options form. If "Input File" date is already present in current records the data WILL NOT be processed, however the "Parse File" WILL be parsed as normal. This prevents Total Rainfall being corrupted. Added "Display" menu item. This allows various opitions on how many records to display in visual grid on base of main form. Year (eg. 2002) is also available. Corrected graph component to accept 100 X-Axis values. Corrected fault in parse file routine.

v3.2 (01-12-02)

Changed some terrible gramatical errors (whoops). Working on PRINT routine, harder than expected, unfinished. Provided a routine to automatically upgrade version non-compatible data files if required. Repaired fault in "Save As" routine. "Print" routine has been disabled in this version whilst I rewrite the code.

v3.1 (29-11-02)

Included algorithms for Forest, Scrubland and Grassland fire intensity (FI) and danger codes (FFDC,SFDC,GFDC). Environment input panel added to Main Page. Updated parse tags to reflect changes to available danger codes (^fwiffdc^,^fwisfdc^,^fwigfdc^) . Minor help system fixes. Revamped & simplified fwicalc.ini file creation process. Realigned, centred text, buttons, edit boxes etc (neatened the thing up).

v3.0 (26-11-02)

Incorporated FTP & Dial-up Connection procedures. Incorporated 96bit encryption routine for password storage. Revised data file storage system from ascii text based to binary random access system. Required creating two data files per profile (*.fwi = fwi data, *.fws = profile setup). Stress tested application. Simplified date format checking routines & error pickup. Repaired StringGrid TopRow bug. Repaired Fire Danger Rating bug. Repaired FTP timer bug.

v2.1 (19-11-02)

Added 2nd series overlay procedure to graphing routines. Included automatic version updater for data files.

v2.0 (17-11-02)

Designed and incorporated graphing capability.

v1.1 (26-10-02)

Added file parse and HTML table routines. Created Windows help file for application.

v1.0 (13-10-02)

First Beta version written. FWI calculations only.

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