For the website JavaScript version (not needed if you're not JS specialist) and also Win, Mac and Linux apps for downloading. Extremely simple: Customer enters following information: * Space between rows in meters * Space between wines in meters After information entered and "Calculate" button is clicked the calculator will tell "Your density by hectare" And the formula to calculate this = 10000 / (Space between rows * Space between wines) It will be in English, Spanish and French language. Please, do not quote if you can't do it very fast - we need it this week! You can quote this if you can't do JavaScript as we'll do it ourselves. Just write with quote that it's without JavaScript version for website.