These tools can be used to calculate your freelance rate. All you have to do is enter your costs and desired income.
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A simple freelance calculator that works out your appropriate hourly rate.
FreelanceSwitch’s lets you add in all of your costs and desired income and then advises you of your hourly rate. There’s a lot of fields to be completed, however the end result is accurate.
An iOS app for freelancers that calculates how much you should charge your clients for your services.