Inter partes review is the post-grant invalidity tool defendants reach for first when prior art exists and the asserted claims look broad. The PTAB invalidates challenged claims at high rates, the timeline is fast (12-18 months from petition to final written decision), and a stay of the parallel district-court litigation is common after institution. (Background on the post-grant tools →)
It's also expensive. Here's what an IPR actually costs in 2026 — USPTO fees, attorney fees, expert costs, hearing prep — and how to decide whether the spend makes sense for your case.
The headline number
For a typical contested IPR challenging a single patent with 20 or fewer claims, all-in cost from petition through final written decision runs approximately $300,000 to $500,000, including USPTO fees, attorney fees, and expert costs. A petition that doesn't institute costs about $150,000-$200,000 (you've spent the petition-stage money but not the post-institution money). A petition with multiple patents or many claims can exceed $700,000.
Those numbers come from the AIPLA Economic Survey of IP attorney costs, supplemented by recent post-institution data from PTAB statistics and member-firm reports at AIPLA / IPO. Actual costs vary widely by firm rate, technology complexity, and litigation posture — they are lower for routine cases handled by IP boutiques and higher for complex cases at AmLaw 100 firms.
USPTO fees
The PTAB charges a two-tier fee: petition (filing) and post-institution. The full fee schedule is on the USPTO fee schedule page; fees adjust periodically — verify against the live schedule before budgeting. The numbers below reflect the schedule in force as of May 2026:
| Stage | Base fee (claims 1-20) | Per additional claim |
|---|---|---|
| IPR petition request | ~$23,750 | ~$525 over 20 |
| IPR post-institution | ~$33,750 | ~$1,000 over 15 |
So a routine IPR challenging 15-20 claims pays the USPTO about $57,500 total — roughly half upfront when filing the petition, the other half if and when the PTAB institutes review. Larger IPRs can drive the USPTO total over $100,000 — a meaningful but ultimately small fraction of the overall budget.
Post-Grant Review (PGR) fees are roughly the same. Covered Business Method (CBM) review was sunset in 2020. Ex parte reexamination is much cheaper (~$12,000 USPTO fee) but limited to patents/printed-publications-only prior art and doesn't get a stay.
Attorney fees: where the real money goes
Attorney fees on an IPR break into three phases:
Phase 1: Petition drafting (~$120,000-$200,000)
Drafting a competent IPR petition is the most analytically dense work in the whole process. The petitioner has to:
- Identify and develop the prior art (most petitions cite 2-5 references).
- Build claim charts mapping each claim limitation to the cited art.
- Construct anticipation (§ 102) and obviousness (§ 103) arguments with motivation-to-combine analysis. (Background on § 103 →)
- Draft the proposed claim construction under Phillips (since 2018, IPRs use the same standard as district courts).
- Lock in the experts and prepare their declarations.
Typical attorney time: 200-400 hours from a 2-3 person team at $500-$800/hour blended rate. Add 80-150 hours of expert time. AIPLA-survey median for the petition phase alone runs around $150,000.
The petition is also where IPR estoppel risk is locked in — every prior art reference you reasonably could have raised is barred from the parallel litigation if the IPR institutes. (How estoppel works →)
Phase 2: Post-institution discovery and briefing (~$150,000-$300,000)
If the PTAB institutes (the petitioner gets one shot at convincing the panel during a 3-month preliminary phase), the case moves into:
- Patent owner response (the patent holder's brief defending the claims).
- Petitioner reply.
- Limited depositions of declarants — typically 2-4 expert depositions.
- Motions to amend (the patent owner can attempt to substitute narrower claims).
- Sur-replies and observations.
PTAB's twelve-month statutory deadline for the final written decision keeps this phase tightly scheduled. Attorney time: 300-500 hours, plus expert time of 50-100 hours. Costs concentrate around the depositions (each deposition session costs ~$15,000-$25,000 in attorney + court reporter + travel).
Phase 3: Oral hearing (~$30,000-$60,000)
The hearing is a one-hour-per-side argument before a three-judge PTAB panel. Most of the cost is preparation — moot courts, demonstratives, hearing-prep deposition reviews. The actual hearing happens in Alexandria, Virginia or via video; travel and time-day-of are minor.
Expert witness costs
Technical experts are essential — the PTAB strongly prefers expert declarations on motivation to combine, claim construction, and obviousness analysis. Expert costs:
- Hiring and onboarding: $5,000-$15,000.
- Declaration drafting (petition stage): $20,000-$50,000.
- Deposition prep + testimony: $15,000-$40,000 per expert per deposition.
- Hearing prep: $10,000-$30,000.
A typical IPR uses 1-2 technical experts. Total expert cost across all phases: $50,000-$150,000, sometimes more for highly specialized fields (semiconductor process, RF engineering, pharma chemistry).
Other costs
- Court reporter / transcripts: $3,000-$8,000 per deposition.
- Demonstratives / graphics: $5,000-$20,000 (charts, claim diagrams, slides).
- Translation of foreign prior art: $1,000-$5,000 per document if the art is in Japanese, Chinese, Korean, or German (common in semiconductor and electronics cases).
- Travel + hotel for hearings: $3,000-$8,000 per attorney for the hearing day.
Total typical range
Putting it all together, a single-patent IPR through final written decision lands in this range:
| Component | Low | High |
|---|---|---|
| USPTO fees | $25,000 | $100,000 |
| Petition-phase attorney fees | $120,000 | $200,000 |
| Post-institution attorney fees | $150,000 | $300,000 |
| Expert witness costs | $50,000 | $150,000 |
| Other (depositions, demonstratives, travel) | $20,000 | $50,000 |
| Total | $365,000 | $800,000 |
A median real-world IPR at a competent IP boutique lands close to $400,000 all-in. AmLaw firms sometimes run higher; specialty IP boutiques (Sterne Kessler, Erise IP, Banner Witcoff, Schwegman) can come in at the lower end without sacrificing quality.
When IPR pays
IPR makes economic sense when the parallel district-court damages exposure plus defense cost exceeds the IPR cost by a comfortable margin. The rough decision matrix:
| Scenario | IPR worth filing? |
|---|---|
| Damages exposure > $5M, strong prior art | Yes — almost always |
| Damages exposure $1M-$5M, strong prior art | Often, especially if litigation will go past Markman |
| Damages exposure < $1M, strong prior art | Usually not — early settlement is cheaper |
| Any size, weak prior art | No — file fee shift threats instead |
| Multiple defendants, shared prior art | Yes, if costs split among 3+ defendants |
| Patent already in IPR by another defendant | Join existing IPR (much cheaper) instead of filing new |
The classic case for filing: a non-practicing entity asserts a single broad software patent against multiple defendants, demanding $5M-$20M in license fees per defendant. A $400,000 IPR — split four ways with a joint defense group at $100K per defendant — kills the whole campaign. This is the bargain that made IPR so consequential after the America Invents Act introduced it in 2012.
When IPR doesn't pay
- Damages are too small. Below ~$1M in exposure, settlement at 10-30% of demand is almost always cheaper than $400K of IPR.
- The prior art is weak. PTAB institution rates run around 60-70% historically and have fallen modestly in recent years. If your prior art doesn't already look like a strong § 102 or § 103 case in informal review, the petition probably won't institute, and you've spent $150-200K.
- You're already past Markman. Apple v. Fintiv (and its successors) gives the PTAB discretion to deny institution where parallel litigation is far advanced — courts that "would be done before the PTAB writes a final decision" generate Fintiv denials.
- The patent is too narrow to bother. If the patent's claims are very specific and your product has obvious non-infringement defenses, a non-infringement summary-judgment motion is cheaper.
Cost-reduction tactics
Join an existing IPR
If another defendant has already petitioned, joining as a party is dramatically cheaper than filing a separate IPR — typically $50,000-$150,000 instead of $400K+. PTAB rules on joinder are favorable to defendants who are also being sued on the same patent.
Limit claims challenged
The post-institution USPTO fee scales per claim above 15. Challenging only the claims actually asserted against your product (not every claim in the patent) saves both USPTO fees and attorney drafting time. Most well-run petitions challenge 8-15 claims, not 30+.
Use a focused 2-3 reference invalidity case
Strong IPRs tend to have 2-3 anchor references that map cleanly. The petitioner's instinct to load the petition with 8 references "in case one fails" is usually counterproductive — it dilutes the analysis and creates extra deposition cost.
Joint defense economics
A Joint Defense Group of 3-5 defendants splitting an IPR can drop the per-defendant cost to $80K-$120K. RPX Corporation and Unified Patents both run JDG infrastructure; member companies regularly co-file or share invalidity workups. This is the single largest cost lever available.
File early, before discovery balloons
IPRs filed in the first 6 months after a complaint tend to cost less than IPRs filed after a year of district-court discovery. Once depositions and document discovery are running, your attorney is already paying for parallel work, and the IPR loses some of its cost-isolation benefit.
Settle the IPR instead of running it to FWD
A surprising fraction of IPRs settle after institution — the parties resolve the parallel litigation, and joint termination of the IPR follows. If your settlement leverage is strong post-institution, you may pay only the petition-phase costs ($150K-$200K) and capture much of the upside.
Comparison to district-court litigation
A patent suit defended through trial costs $3,000,000 - $5,000,000 for a typical defendant. Through summary judgment: $1.5M-$3M. Through Markman: $750K-$1.5M.
Even at the upper end of IPR cost, the comparison is favorable:
| Stage | Defense cost |
|---|---|
| IPR through FWD | $300,000 - $500,000 |
| Litigation through Markman | $750,000 - $1,500,000 |
| Litigation through summary judgment | $1,500,000 - $3,000,000 |
| Litigation through trial | $3,000,000 - $5,000,000 |
The bargain: IPR can end the entire matter for the price of a Markman, with a stay of the litigation in the meantime.
What an IPR final written decision actually does
If the PTAB invalidates challenged claims, those claims are canceled as a matter of public record. The patent holder cannot assert them against any defendant in any court. The estoppel cuts both ways: the petitioner is barred from re-litigating any prior art the petitioner reasonably could have raised in the IPR. (How estoppel works →)
If the PTAB confirms validity, the patent holder gains a meaningful enforcement advantage — defendants now face a strong presumption against re-litigation of the same prior art.
Bottom line
An IPR through final written decision typically costs $300,000 - $500,000 all-in. About $50,000 of that is USPTO fees; the rest is attorneys and experts. The cost is meaningful, but compared to a $3M-$5M trial defense, it's a bargain when the prior art is real and damages exposure is large.
The biggest cost lever is joint defense — splitting an IPR among co-defendants drops per-party cost to $80K-$120K and turns IPR into the dominant first-line defense for any well-organized response to NPE assertions.
This article is for general education and is not legal advice. Specific IPR cost depends on your firm, your facts, and your patent. Get a quote from an experienced PTAB practitioner before committing.