It usually takes about 5 years after the provisional filing date before a patent is granted. A US non- provisional application is filed 2 and a half years after the provisional, and each round of office actions and responses takes at least six months. Slow prosecution can have the advantage of deferring costs until after your next round of fundraising.
If you want to obtain a patent quickly, prosecution can be compressed to less than one year by immediately filing a US non-provisional application, paying for expedited processing, filing narrow claims that won’t provoke the examiner to issue a restriction requirement or multiple rejections, and responding to office actions in a timely manner.
