If your prior university do not have any information on their credit system you must document how many credits that forms one year of full time studies in another way – e.g. through the curriculum of your programme. At the Faculty of Science, University of Copenhagen, a full time study is 15 ECTS credits per block - in total 60 ECTS credits covers 1 year of full time studies.
When you have the number of credits from your prior university, you can calculate how many of your credits that corresponds to our ECTS credits. If one year of full time studies at your prior university for instance are 100 credits then 1 of ours ECTS credits corresponds to 100/60=1.67 of your credits. Then you can use this number to calculate the corresponding ECTS credits for one of your courses. If for instance one of your courses gives you 20 credits, then it will corresponds to 20/1,67= 12 ECTS credits.