the part most freelancers skip is separating taxes from actual take-home when they set their rate. A rate that looks great gross can be sobering once income tax, NI (or your local equivalent), pension and unpaid holidays come off.
I run a free UK take-home pay calculator at TakeHomePayPro (https://takehomepaypro.co.uk/) for UK-based readers it's a quick sanity check on what a day rate actually leaves you with each month after deductions. Worth running your "true rate" through something like that before quoting it to a client.