A continuation patent application pursues more claims from a specification you already filed.
A divisional carries claims the examiner made you drop. One is voluntary, the other responsive.
Both share the parent's disclosure and priority date, and both expire with it. They add coverage, never term.
And the window for either closes when the parent issues with nothing else pending — permanently, without any reminder.
The three continuing application types
| Type | Adds new matter | Priority | Why filed |
|---|---|---|---|
| Continuation | No | Parent's | Further claims you want |
| Divisional | No | Parent's | Claims the examiner made you drop |
| Continuation-in-part | Yes | Split by matter | Adds an improvement |
All three expire with the earliest parent. See CIP patent for the split-priority problem the third one creates.
Why continuations are valuable
| At original filing | Three years later |
|---|---|
| You guess what competitors will build | You can see it |
| Claims aimed at your own concept | Claims aimed at their product |
| Prior art partly unknown | Examiner has searched it |
| Market unproven | Market visible |
That hindsight advantage is the whole point. A continuation lets you write claims covering what the market actually produced, using a specification filed years earlier.
Nothing else in patent practice offers this. It is the reason sophisticated portfolios keep one application pending at all times.
The restriction requirement
| Issued when | The examiner considers the claims cover distinct inventions |
| Common in | Applications claiming a device and a method of making it |
| You must | Elect one group for examination |
| Non-elected claims | Survive only in a divisional |
| Deadline | Before the parent issues |
| Safe harbour | Divisionals get protection against certain double patenting rejections |
Non-elected claims are lost permanently if no divisional is filed before the parent issues. The restriction requirement is the notice; nothing reminds you afterwards.
The window
| Available while | A parent or earlier continuation is pending |
| Closes | When the parent issues with nothing pending |
| Reminder | None |
| Reopenable | No |
| Effect of missing it | The family is closed permanently |
The parent granting feels like success, and the option disappears in the same moment. That is why this is the most commonly missed decision in a patent's life.
Keeping one continuation pending costs that application's fees and preserves the whole capability.
Divisional versus continuation in practice
| You want | File |
|---|---|
| Claims the examiner made you drop | Divisional |
| Further claims of your own choosing | Continuation |
| Broader claims from the same disclosure | Continuation |
| Claims aimed at a competitor product | Continuation |
| Double patenting safe harbour | Divisional, after restriction |
The safe harbour is a real advantage of the divisional route where a restriction requirement was issued.
Why families close by accident
| Cause | Detail |
|---|---|
| Allowance reads as success | Nobody thinks about further filings |
| No reminder exists | Not a calculated date |
| Issue fee paid promptly | Closes it |
| Counsel reports the grant | Not the closing window |
| No named owner | The root cause |
Diarise the decision on notice of allowance, not on the issue fee.
Copendency is required
| Requirement | Detail |
|---|---|
| Filed while a parent is pending | Not after it issues |
| Chain must be unbroken | A gap breaks priority |
| Specific reference to the parent | In the ADS |
| Common inventor | At least one |
| Common ownership | For terminal disclaimer purposes |
A gap in copendency breaks the chain, and with it the priority claim. Challengers look for this because it is free to establish from public records.
Term runs from the earliest parent
| Filing | Own filing date | Expires |
|---|---|---|
| Parent | 2016 | 2036 |
| Continuation | 2020 | 2036 |
| Divisional | 2021 | 2036 |
| Continuation | 2024 | 2036 |
A continuation filed in 2024 from a 2016 parent has twelve years left, not twenty.
Check Related U.S. Application Data on the front page before calculating any expiry. Buyers, defendants and sellers all miscalculate this. See patent family.
Reading a family's continuity data
| Source | Shows |
|---|---|
| Front page, Related U.S. Application Data | The chain |
| USPTO Patent Center continuity | Parents and children |
| Espacenet | Worldwide family |
| Google Patents | Related applications |
Check continuity before calculating any expiry date. The filing date shown is frequently not the one that governs.
Claim strategy across a family
| Member | Typical claims |
|---|---|
| Parent | Whatever was allowable first |
| Continuation 1 | Broader, or aimed differently |
| Continuation 2 | Written toward a competitor's product |
| Divisional | The non-elected invention |
| Later continuation | Narrower fallbacks |
Depth is what makes a family hard to design around. One broad claim can be invalidated or avoided; claims at several levels leave fewer routes.
Build it while the window is open. Once the family closes, the specification is still there and nothing further can be claimed from it.
What each costs
| Item | Continuation or divisional |
|---|---|
| USPTO fees | Similar to a new application |
| Drafting | Far less — the specification exists |
| What you write | Claims only |
| Prosecution | Depends on reception |
| Maintenance fees | Its own full set |
| Fee | Due after grant | Large | Small | Micro |
|---|---|---|---|---|
| First | 3.5 years | $2,150 | $860 | $430 |
| Second | 7.5 years | $4,040 | $1,616 | $808 |
| Third | 11.5 years | $8,280 | $3,312 | $1,656 |
| Total per member | $14,470 | $5,788 | $2,894 |
Each family member carries its own maintenance fees. A family of five large-entity patents carries over $72,000 across their lives, which is the real cost of depth.
What the specification allows
| You can claim | You cannot |
|---|---|
| Anything the parent disclosed | Anything it did not |
| Narrower versions | New matter |
| Different aspects of the same disclosure | Improvements developed since |
| Method claims from an apparatus disclosure | If supported |
The original specification is the ceiling for the whole family. A thin disclosure limits what every continuation can ever cover, however many you file.
That is the argument for generous drafting at the start, and it is decided years before anyone thinks about continuations. See how to write a patent application.
Double patenting and terminal disclaimers
| Situation | Consequence |
|---|---|
| Continuation claims obvious over the parent | Obviousness-type double patenting rejection |
| Remedy | Terminal disclaimer |
| Effect | Caps the later patent's term to the parent's |
| Also requires | Common ownership |
| Divisional after restriction | Safe harbour applies |
Terminal disclaimers are routine in continuation families and they are why family members expire together even when filed years apart.
Divisionals filed in response to a restriction requirement are protected from certain of these rejections, which is a real advantage of the divisional route.
Worked example: keeping a family open
| Year | Action | Result |
|---|---|---|
| 2018 | Non-provisional filed | Parent |
| 2020 | Restriction requirement | Divisional filed — method claims preserved |
| 2021 | Parent allowed → continuation filed | Family stays open |
| 2022 | Competitor product launches | Now visible |
| 2022 | Continuation claims written toward it | Hindsight advantage |
| 2024 | Second continuation filed | Family still open |
| All members expire | 2038 | From the 2018 parent |
| Outcome | |
|---|---|
| Members | 5 patents |
| Coverage | Broad claim, method claims, claims aimed at a real product |
| Design-around difficulty | High |
| Cost | 5 sets of maintenance fees |
The 2022 continuation is the valuable one and it existed only because the family was never allowed to close.
The divisional preserved claims that would otherwise have been abandoned at the restriction requirement in 2020.
One rule to remember
File before the parent issues. Everything else is detail.
The paperwork
| Item | Detail |
|---|---|
| New Application Data Sheet | With the benefit claim to the parent |
| Specification | Identical to the parent |
| New claims | The point of the filing |
| Declaration | May be able to reference the parent's |
| Fees | Filing, search, examination |
| IDS | Art known, including from the parent's prosecution |
The benefit claim in the ADS is the critical entry. Omitting it or getting it wrong loses the priority date, which is the whole reason for filing.
When not to file one
| Situation | Assessment |
|---|---|
| Nobody practises the claims | Weak case for depth |
| Remaining term short | Continuation expires with the parent anyway |
| Budget constrained | Each member costs full maintenance fees |
| No competitor visibility yet | Wait — but the window closes |
| Specification thin | Nothing further to claim |
The last one is the constraint people discover late. A continuation can only claim what the original specification supports, so a narrow disclosure limits what the whole family can ever cover. See how to write a patent application.
Cost of keeping one pending
| Item | Detail |
|---|---|
| Filing fees | Per application |
| Drafting | Claims only — far less |
| Prosecution | If it draws rejections |
| Maintenance if it grants | A full set |
| Value | The option to claim what competitors build |
The option has real value and a real price. Keeping a family open indefinitely means maintaining whatever grants.
Prosecution differs from the parent
| Parent | Continuation | |
|---|---|---|
| Examiner | Assigned | Usually the same |
| Prior art | Searched | Already known |
| Claims | New | The point |
| Double patenting | Not applicable | Likely raised |
| Speed | Standard queue | Sometimes faster |
The examiner already knows the art, which can make continuation prosecution faster and more predictable than the parent's.
Expect an obviousness-type double patenting rejection and budget a terminal disclaimer.
The decision at allowance
| Step | Detail |
|---|---|
| 1 | Notice of allowance arrives |
| 2 | Ask: is there more to claim from this specification? |
| 3 | Ask: can competitors design around the allowed claims? |
| 4 | Ask: has the market revealed anything since filing? |
| 5 | If yes to any — file before the issue fee is paid |
| 6 | Pay the issue fee within 3 months, no extension |
Diarise this decision when the notice of allowance arrives, not when the issue fee is due. They are different moments and the second is too late to think about it properly.
Before filing one
| Check | Detail |
|---|---|
| Is the parent still pending? | The whole requirement |
| Is there more the specification supports? | Otherwise nothing to claim |
| Has the market revealed anything? | The hindsight advantage |
| Can you fund the extra maintenance fees? | A full set per member |
What you are buying
| Coverage | Additional claims from the same disclosure |
| Optionality | The family stays open |
| Hindsight | Claims aimed at real products |
| Not term | Expires with the parent |
| Cost | Filing, prosecution, and its own maintenance fees |
Optionality is the underrated part. Keeping a family open costs one application's fees and preserves every future claiming decision.
When to file the continuation
| Timing | Assessment |
|---|---|
| On notice of allowance | Standard |
| Earlier, alongside prosecution | Also possible |
| After the issue fee is paid | Too late if the patent has issued |
| From an existing continuation | Keeps the chain going |
Foreign equivalents
| US | Elsewhere | |
|---|---|---|
| Continuation practice | Flexible | More restricted |
| Divisionals | Available | Widely available |
| Unlimited chains | Yes | Frequently not |
| Deadline | Parent issuing | Varies |
US continuation practice is unusually permissive. Strategies built on keeping a chain open indefinitely do not transfer to every jurisdiction. See international patent law.
What most patents become
| Ipiry Patent Survival Curve v1.0 | Rate |
|---|---|
| Survive the 3.5-year fee (2022 cohort) | 85.8% |
| Survive the 7.5-year fee (2018 cohort) | 64.6% |
| Reach full term (2014 cohort) | 41.4% |
| Abandoned before full term | 58.6% |
Computed from 27,273,654 USPTO maintenance fee records covering 8,262,336 US utility patents — see the patent survival curve.
Depth costs money every year. Building a five-member family is a real commitment, and the decision to keep each member comes back three times.
Continuation and divisional applications: the checklist
- A continuation is voluntary; a divisional is responsive to a restriction requirement.
- Neither adds term. Both expire with the earliest parent.
- The window closes when the parent issues with nothing pending. No reminder.
- Keep one application pending to keep the family open.
- File the divisional before the parent issues, or non-elected claims are lost.
- Use continuations to claim what competitors built. That is the hindsight advantage.
- Calculate expiry from Related U.S. Application Data, never the filing date shown.
- Budget maintenance fees per member, not per family.
- Expect terminal disclaimers in continuation families.
- Remember the specification is the ceiling. A thin disclosure limits the whole family.