A common question startups have regarding patents is "Can I put more than one invention into my patent application?"
The simple answer is "yes". The less simple answer is "yes - but the patent examiner may ask you to split them into separate patent applications later".When you file your patent application you have to pay the US Patent and Trademark Office (USPTO) a "filing fee", a "search fee" and an "examination fee". The total of all three of these fees is currently $400 for inventors who can qualify as a micro entity status. If you have more than one invention in your application, an Examiner at the USPTO will likely ask you to separate them out because you only paid the USPTO one fee for one search and one examination. Each different invention needs to have it's own search and examination done.
Why squeeze multiple inventions into just one application?
The main reason people want to add multiple inventions into a single patent application is cost savings. If you have multiple inventions, one cost-saving strategy is to combine as many inventions as you can into a single application and pay just one fee filing fee (you will still have to pay for attorney time).
You can go back later and separate them out as needed or wait for the examiner to force you to separate them.
* Note, if the inventions are really all the same invention with different variations then you can and should file the variations in a single application.
The downside to multiple inventions in a single application?
There are risks and drawbacks to combining multiple inventions into the same patent application.
One drawback is that all the inventions filed in the same application will be given the same expiration date. If you want to extend the life of some of the inventions you stagger their filings.
Another potential drawback is that patents and patent applications can be very valuable assets to a company. If you have just one patent or patent application, some investors or potential business partners may not value that as much as if you had multiple patents or patent applications. A new start-up company could potentially get more funding if they had multiple patents surrounding their inventions versus just having filed a single patent application.