Latest Info

TriLookup Users




Latest Information on TriLookup

Date Posted Description


As of March 27, 2020, TriLookup is free for all future and current users, without any restrictions as to the type of use or the number of users. To register and activate your free copy of TriLookup please use the credentials below.

Registered User Name: TRILOOKUP
Registration Code:      
Number of Licenses:     Unlimited

We have also made the full 64 version of TriLookup available for free download. The 64 version doesn't require registration.

The source code is still protected, but we are planning to eventually change TriLookup to Open Source. If you would like to get an earlier access to the TriLookup source code, please contact us at info@trimill.com


Version 3.0

·         Introduced TriLookupLite as a freeware edition of TriLookup.

·         Rewritten portions of the TriLookup user’s manual and Help File.

·         Updated Website .


Version 2.4

·         Added automatic installation for Excel 2010.

·         Fixed the NumLock bug in Excel 2007 and 2010 (TriLookup would turn the NumLock off after starting Excel).


Version 2.3

 ·         From this release forward, TriLookup will also install automatically on Excel for Windows versions 2013 and 2016.

·         From this release forward, a version of TriLookup is also available for Excel 64 bit. Due to restrictions imposed by 64 bit Excel, this version differs from the regular TriLookup in a few details, as follows:

o   All dialogs and menu entries removed.

o   The TriLookup functions appear in the "Lookup & Reference" category of the Insert Function dialog (not a separate TriLookup category like in the 32 version).

o   This version does not allow for 30-day evaluation and does not require the registration code to be activated. For that reason it is available only to registered TriLookup users by email request to info@trimill.com at no additional cost (our policy doesn’t include making money by selling you the same software over and over again).

o   This version also works on Excel 2011 for Macintosh, which doesn’t support regular TriLookup. Unfortunately, no version of TriLookup works on Mac Excel 2008 because, due to strange wisdom that has been guiding Microsoft, that one doesn’t support VBA.

·         New feature was added in TVPOLYDATA and THPOLYDATA functions. They now have one more optional parameter at the end, called QR_mode. When QR_mode is set to True (default is False), TriLookup will solve the least squares equation using Householder QR decomposition method (for more details on QR decomposition method see https://en.wikipedia.org/wiki/QR_decomposition). When QR_mode parameter is omitted or set to False, Excel's internal MINV function is used. The functions are otherwise backward compatible with existing spreadsheets.


Version 2.2

·        From this version on TriLookup will also work on Excel for Macintosh versions 98, 2001, and X.

·        Fixed a bug in the TVPOLYDATA and THPOLYDATA functions that caused R² to be calculated as 1 when the actual value of R²  was less than 0.01.

·        Changed the way the best fit curve is determined by the TVPOLYDATA and THPOLYDATA functions. The curve with the maximum value of R² is selected as the best fit curve, as stated in TriLookup documentation. Previous versions picked the curve with the minimum Sum(Error²). While in most cases the maximum R² corresponds to the minimum Sum(Error²), sometimes the two don't coincide.

·        TriLookup example workbooks were reformatted to use old style Forms controls instead of ActiveX controls on the worksheets. This solved compatibility issue on Macintosh and it also shortens the time required to open the example workbooks.

·        A new combo box has been added to the worksheets in the Interactive Examples workbook which lets you select whether or not to hide the #N/A points on the line diagrams. The process of removing the #N/A points can take a long time on a slow computer.

·        Starting in this version, the evaluation version of TriLookup will stop functioning after 30 days and all TriLookup functions will return the following message:

“Error: TriLookup 30 day evaluation period expired!”


Version 2.1

·        A new parameter called Index_mode has been added to the TVLOOKUP, TVLKP, THLOOKUP, THLKP, TVPOLYDATA and THPOLYDATA functions. Index_mode is used to explicitly choose the way lookup and return rows/columns are selected: either by their titles (Index_mode = FALSE), or by their index number, i.e. the position in Table_array (Index_mode = TRUE).

Note that in version 2.0 the way of identifying lookup and return rows/columns was not explicitly specified. Instead, identifying a row/column by its title took precedence over specifying it by its index number, which in some cases could have caused ambiguity regarding which row/column is being selected. This ambiguity has been eliminated with the addition of the Index_mode parameter.

Note that Index_mode is the last parameter in the list, it is optional and its default value is FALSE. Therefore, the formulas created with TriLookup versions 1.x, (which only allows selecting lookup and return rows/columns by titles) will not be affected and can be used without modifications. However, the formulas created with TriLookup version 2.0 that implicitly use row/column selection by index number, have to be modified by setting Index_mode = TRUE.

Thanks to Mark Ivanov from EchoStar Satellite Corporation for suggesting the option of specifying lookup and return rows/columns by position, and for pointing out the shortcomings of the method implemented in Version 2.0.


Version 2.0

·        Thanks to Laurent Longre’s FunCustomize.dll add-in, the problem described in section Problem After Moving Old Workbooks with TriLookup Functions to Another Computer was eliminated. The new workbooks will automatically reference TriLookup 2.0 if you refer to any of the TriLookup functions in the cell formulas. The references will stay valid after the workbook is moved from one computer to another.

·        Thanks to Laurent Longre’s FunCustomize.dll add-in, the Formula Palette dialog now also displays a short help message for each of the function parameters.

·        In addition to identifying the lookup and return rows/columns by their titles, you can now also use the Lookup_title and Return_title parameters to specify the lookup and return rows/columns by their position in Table_array (1 for the first row/column, 2 for the second row/column, etc.).  The affected functions are TVLOOKUP, TVLKP, THLOOKUP, THLKP, TVPOLYDATA and THPOLYDATA.

·        The TriLookup functions now appear in a separate TriLookup function category in the Paste Function dialog.

·        Fixed the bug that caused T2LOOKUP, T2LKP, T3LOOKUP and T3LKP functions to return a #VALUE error when the number of rows multiplied by the number of columns exceeded 32767.


Link to Version 1.2 Fixed

If you downloaded and installed version 1.2 between January 15 and January 21 2004, chances are that you got the version 1.1 again because of an incorrect link on the TriLookup Download page. If this is the case, you should download version 1.2 again and reinstall it.


Version 1.2

  • The setup program will now also install TriLookup for Excel 2003 in addition to Excel 97, 2000 and 2002 (XP).

  • Fixed a bug in handling extrapolation for Interpolate (X/Y/Z_interpolate) = 6, when the values of the last three points in the series (the ones used to calculate the extrapolated result) are not uniformly ascending or uniformly descending, i.e., they produce a local maximum or a local minimum.

    Versions 1.0 and 1.1 return Excel’s #VALUE error, even for Error_msg = TRUE.

    Version 1.2 returns a #N/A error, or if Error_msg = TRUE the following error message:

“N/A {Err.315} Cannot extrapolate for Interpolate = 6, when the end 3-point segment has a minimum or a maximum.”

  • Changed the way extrapolation is performed when Interpolate (X/Y/Z_interpolate) = 6.

    Versions 1.0 and 1.1 extrapolate by extending the hyperbolic curve defined by the end 3-point segment. Due to divergent nature of the hyperbolic curve, this usually leads to highly unpredictable results.

    Version 1.2 extrapolates by extending the tangent drawn through the end point of the hyperbolic curve defined by the end 3-point segment. The extrapolated values now lie on a straight line, which makes the results of extrapolation much more predictable.

  • Fixed a bug in the TriLookup Interactive Examples.xls workbook which prevented hiding of the #N/A points on the line graphs.


Version 1.1

Some minor changes and bug fixes:

  • Added switching to manual calculation when loading interactive example to avoid recalculation.

  • Fixed a bug in processing tables with constant Y values in TVPOLYDATA and THPOLYDATA.


The following error message window pops up when you try to use TriLookup example workbooks in Excel XP (2002):

Error: 1004: Programmatic Access to Visual Basic Project is not trusted


Microsoft Excel 2002 contains a new security feature that allows you to choose whether or not programmatic access to the Visual Basic project should be trusted.
The default setting is to not trust programmatic access to the Visual Basic project.

TriLookup uses programmatic access in order to establish reference from the example workbooks to TriLookup.xla.

Resolution Option 1

To allow programmatic access to TriLookup, and all other Visual Basic projects, follow these steps:

  1. On the Tools menu, point to Macro and then click Security.
  2. In the Security dialog box, click the Trusted Sources tab.
  3. Click to select the Trust access to Visual Basic Project check box.

Resolution Option 2

To remove programmatic reference from the example workbooks, follow these steps:

  1. Press <Alt><F11> to open Visual Basic Editor.
  2. Locate the name of the workbook in the Project Explorer window and click on it.
  3. Click on Modules and then on double click on mMain.
  4. Find Sub InitializeWorkbook() and comment our or delete the following line:
  5. GetTriLookupReference
  6. Close Visual Basic Editor and save the example workbook under a different name.  


Version 1.0

• Initial release of TriLookup

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