I have used the information from the wiki and created a Libreoffice Calc spreadsheet that features the calculation. It is divided into several leaves whereas the first one requires you to insert data. The other leaves are just for data storage and calculation. The shown review score in the first leave is one of the possible review scores for your game that you will see ingame. Keep hitting F9 to cycle through all possible review scores. For experts: You can take a look into the calculations leave and find out your game score, target game score and some more things.
ATTENTION:
This spreadsheet doesn’t consider the penalty because of bugs or releasing a sequel less than 40 weeks after the previous game. Trends are not considered as well. So you’ll have quite good results when you release games without bugs and outside of trends. Of course you shouldn’t release a sequel within 40 weeks after the previous game either. In addition you should avoid using the same topic/genre combination though that is considered in the calculator.
And most of all it only works with one genre.
Most of all you will know your real review score that is calculated by the program. The shown review score in game is not the calculated one. In fact it can be even more than 1 point more or less. To prove that try the following:
Save the game when you have finished creating a new game (before clicking on finish). Then click on finish and wait for the review score. Write it down and load and repeat it. When the shown review scores are different you will know that these are not your real review scores used by the game for calculation of future target gamescores, top gamescores, etc.
And here’s finally the link:
http://jimmartens.bplaced.net/games/gameDevTycoon/GameDevQualityCalculator.ods
Have fun.