Scale Soaring UK

Hello all.
Is there anyone who can tell me how to determine the CG if it is not mentioned in the plans or manual? I have asked the same question in our Dutch forum but the answers were not so usefull to me. Is there a formula or something like that?
Regards,
Timo
The Netherlands

Lots of cg calculator programmes out there Timo - such as https://www.ecalc.ch/cgcalc.php

Simon