There are a few things you’ll need to consider when setting your crowdfunding target.
First, determine what your needs are.
Have an estimate from your publisher, publishing team, or a freelancer? Use that as your target.
Need to cover living costs while you finish your first draft? Figure out how much time you’ll need to write it and what that time will cost you.
Want to do some promotion for your book? Do some research to figure out the costs.
Remember to include the cost of crowdfunding.
You’ll now have a starting number. Add to this the cost of platform fees (5% + credit card processing) and reward fulfillment. If these are costs that you’re prepared to shoulder on your own, you won’t need to add these to your target. If you’re not, you’ll want to include them and make sure that you can still cover some of these costs if your target falls short. A safe bet is to add 15% of your goal to your campaign target to cover your costs.
Now that you’ve got a good idea about how much you’ll need to raise, think about whether you can afford to proceed with your plans if you do or don’t raise all that money. If you’re raising funds to work with a specific publisher, chances are you’ll need an all-or-nothing campaign (where the funds will not be charged to your funders if you don’t meet your target) unless you can cover the rest of the costs yourself.