Maidenhead grid calculator for Windows by OH2ECG


On this page you can download a simple Windows program that calculates distances and bearings between two Maidenhead grid locators. The Maidenhead grid is used extensively by radio amateurs to easily provide location information in a very condensed form. Many on-line services and ham utility programs provide tools for calculating the distance and bearing from one grid locator to another. This little stand-alone program is a handy and fast off-line utility you can keep running all the time for rapid access in a spare spot on your screen.

Installing and using the software

The software is delivered as a ZIP-package containing one executable gridcalc.exe and two settings files. Download the ZIP-file using the link at the end of this page and extract the files inside to an empty directory on your computer

Double click the gridcalc.exe executable or use your preferred method to start the software. Once the program is started, it will display a simple window waiting for your input:

The software will accept 1 to 6 -character grid locators. First enter your own locator in the My locator field and then the target locator in the DX locator field.

The software will recalculate the bearing and distance everytime a new character is entered. You can also enter space or question mark instead of a valid locator character. In this case the software will estimate the values to the midpoint of the possible values for the character. The same estimation happens if a locator has an odd number of characters. This may become handy when you're having problems copying the locator of the DX and are trying to turn your antenna towards it with partial locator information.

The calculated values will also automatically be recalculated as you type in more accurate locators with 4 or 6 characters:


The software comes with two text files gridcalc.ini and main.ini that contain various settings, parameters, user interface texts, values saved between sessions etc. Feel free to examine and modify these using your favorite text editor. Most probable candidates for modification have been documented inside the files.

Units of distance and angle

The software is shipped with kilometers as the unit of distance and degrees as the unit of angle. You can change these by providing multipliers in the gridcalc.ini file:
As an example if you want to see the distances in miles and angles in grads, change these to:
In this case you probably also want to change the corresponding user interface texts in main.ini file to something like this:
Item5LBLEnglish=Dir. (grad):
Item7LBLEnglish=Dist. (miles):


The software comes with two built-in user interface languages, English and Finnish. The default language is English. You can switch between the two by editing gridcalc.ini file and 'commenting out' the undesired language with a semicolon character:
; Select the user interface language by uncommenting the desired line.
You can also create your own translation using the following procedure:

1) Comment out all the current languages in gridcalc.ini and add the name of the new language like this:

; Select the user interface language by uncommenting the desired line.
2) Make copies of all ItemXLBLEnglish items in main.ini file, change the name of the language to the one you defined above and then provide your own translations as is done for the first item below:
Item1LBLEnglish=My locator:
Item1LBLFinnish=Oma lokaatt.:
Item1LBLKlingon=wI' Daq 


This software is purely a personal contribution, it is not a product of any company.

I provide this software free of charge to the ham radio community and other parties who may find it interesting or useful. There is no support and absolutely no guarantees for this software.

You are free to use this software for any purpose be it personal, academic or commercial as long as you understand and comply with all the conditions presented in this section ('Disclaimers'), otherwise you are not allowed to download or use this software.

These terms apply to the software available for public download at the moment. The terms of possible future versions of this software may change at any time without prior notice.


Please read the disclaimers in the above section first. Once you've read and agreed to them you can download the latest version of the grid calculator software from here:

Download Maidenhead grid calculator for Windows by OH2ECG v1.1 (135 kilobytes)

Version history


If you have any comments about this software, you're welcome to e-mail me to If you are a ham radio operator and find it useful, your paper QSL card via the bureau as a simple greeting without QSO info would be appreciated.

13th June 2015
73 de Ari Paananen OH2ECG