How to write a provisional patent application

A provisional patent application gives an invention a US filing date with less formality than a full application. It is not examined, and it lasts 12 months. To keep that date, a full (non-provisional) application has to be filed within the 12 months. That full application can rely on the provisional only for what the provisional actually describes.

So the real job when writing a provisional is not the paperwork. It is describing the invention completely enough that a later application has something solid to stand on.

What goes in a provisional application

• A written description: what the invention is, how it is made, and how it works.
• Drawings, where they are needed to understand the invention.
• A cover sheet naming the inventors and the title.
• Claims are optional. Many drafters include at least one anyway, because writing a claim forces clarity about what the invention really is.

A section-by-section way to write it

1. Start from what you already have. Gather the invention notes, sketches, code, test results and emails that explain the idea. Most of the description is already in them; it just isn't organized.

2. Name the field and the problem. One sentence on the field, then a short, factual paragraph on the problem the invention solves. Avoid criticizing specific products.

3. Summarize the solution. In plain language, describe the invention's main parts and what they do together. Every element you might later claim should appear here.

4. Write the detailed description. This is the section that matters most.

• Describe each part, and how the parts connect and interact.
• Explain how the invention is used, step by step.
• Add alternatives: other materials, shapes, orders of steps, or ways to implement it ("in some embodiments…"). A description that shows only one version gives a later application less room.
• Include the hard details: ranges, parameters, specific configurations. A filing date covers only what is actually disclosed.

5. Consider at least one claim. A broad claim that lists the essential elements, plus a few narrower claims that add detail.

6. Read it as a stranger would. Could someone skilled in the field build and use the invention from this document alone? If a step depends on something left in your head, write it down.

Common gaps

• Describing only the prototype, not the variations.
• Listing parts without saying how they connect or work together.
• Leaving out the detail that makes the invention work.
• Treating the provisional as a placeholder and planning to "fill it in later". Later additions do not get the earlier date.

See what a complete draft looks like

Our annotated provisional patent application example walks through every section of a synthetic everyday invention. The PatentAgents.ai sample draft shows a full application from title to claims, with no account needed.

Explore a sample draft