With the following calculation you can determine your target amount:
The actual amount you need to realize your project
+ 5% reserve
+ cost of goodies (incl. shipping)
+ budget for PR / marketing of project (optional)
+ platform comission (around 10%)
= Target amount for crowdfunding
But consider carefully whether your target amount for your crowdfunding is realistic. If the amount is not collected within the specified period, all collected money will be returned to your supporters. (All-or-nothing principle.)
In Switzerland, the average target amount of successful projects is around CHF 10,000.
Higher target amounts are of course possible, but require a particularly great project and a great deal of commitment on the part of the project initiators.
Crowdify also offers the possibility of a stage funding. This allows you to divide your target amount into several sub-targets and reduce the risk of your project failing completely.
However, this only makes sense for projects that can be easily subdivided into different sub-projects.