Reasonable Royalty Patent Damages: How Courts Set the Number

When a patent is infringed and the owner cannot prove lost profits, the law falls back on a floor: reasonable royalty patent damages. Under 35 U.S.C. § 284, a court must award damages “adequate to compensate for the infringement, but in no event less than a reasonable royalty for the use made of the invention.” That single sentence drives a large share of the money in US patent litigation, and yet what counts as “reasonable” is one of the most contested questions in the field. This guide explains how the number is actually built, and what separates an analysis that holds from one a court throws out.

What Are Reasonable Royalty Patent Damages?

Reasonable royalty patent damages are the compensation a court awards for infringement when the patent owner does not, or cannot, prove lost profits. The statutory basis is 35 U.S.C. § 284, which sets the reasonable royalty as a damages floor rather than a ceiling. It answers a specific question: what would a willing licensor and a willing licensee have agreed to pay for a licence, negotiated just before infringement began?

Because most patent owners are not direct competitors of the infringer, or cannot meet the strict causation test for lost profits, the reasonable royalty is the damages theory in the majority of cases. A widely cited PwC analysis found that in roughly 80% of cases where courts awarded damages to practicing entities from 2007 to 2016, they awarded reasonable royalties rather than lost profits.

The royalty is usually expressed as a rate applied to a royalty base, the revenue attributable to the infringing product. Getting both the rate and the base right, and defensibly linking them to the patented feature, is the entire game.

The 15 Georgia-Pacific Factors

The framework almost every US court uses comes from Georgia-Pacific Corp. v. United States Plywood Corp., 318 F. Supp. 1116 (S.D.N.Y. 1970). That decision set out 15 factors an expert weighs to reconstruct the hypothetical licence negotiation. They are not a formula; they are a structured checklist of the commercial reality on both sides of the table.

1. Established royalties the patentee has actually received for the patent
2. Rates the licensee pays for comparable patents
3. The nature and scope of the licence (exclusive or not, territory, field of use)
4. The licensor’s policy of maintaining its patent monopoly by not licensing
5. The commercial relationship between the parties (competitors or not)
6. The value of the patented feature in promoting sales of other products
7. The remaining term of the patent and duration of the licence
8. The established profitability and commercial success of the product
9. The utility and advantages of the patent over old modes and devices
10. The nature of the invention and benefits to those who have used it
11. The extent of the infringer’s use and evidence of its value
12. Customary profit or royalty in the particular business
13. The portion of profit attributable to the invention versus other elements
14. Expert testimony on a reasonable royalty
15. The outcome of a hypothetical arm’s-length negotiation between the parties

A rigorous analysis does not simply recite all fifteen. It shows which factors actually move the rate on the facts of the case, and ties each to real evidence, an existing licence, a comparable transaction, a profit study, rather than to assertion.

The Fall of the 25% Rule: Uniloc v. Microsoft

For decades, damages experts leaned on the “25% rule of thumb”: start by assigning 25% of the infringer’s profit on the product to the patent, then adjust with the Georgia-Pacific factors. The Federal Circuit ended that practice in Uniloc USA, Inc. v. Microsoft Corp., 632 F.3d 1292 (Fed. Cir. 2011), holding “as a matter of Federal Circuit law that the 25 percent rule of thumb is a fundamentally flawed tool.”

The court’s reasoning matters for anyone building a royalty today: a starting point that bears no relation to the specific facts of the case cannot be rescued by later Georgia-Pacific adjustments. In Uniloc the flawed methodology helped produce a $388 million jury award that was set aside on damages. The decision did not weaken the Georgia-Pacific factors themselves; it required that every input, above all the starting rate, be tied to the real facts and the specific hypothetical negotiation.

The practical lesson is that a modern reasonable royalty must be built from comparable licences and case-specific evidence, not from a convenient percentage. This is also why disciplined IP valuation work, benchmarking real arm’s-length licences, has become central to credible damages testimony.

Apportionment and the Royalty Base

Even a well-supported rate fails if it is applied to the wrong base. The apportionment requirement forces the damages to reflect the value of the patented feature, not the whole product. Under the entire market value rule, an expert may use the total product revenue as the base only when the patented feature drives customer demand for the entire product, a demanding standard that courts police closely.

In practice this means isolating the smallest saleable patent-practicing unit, or otherwise carving out the revenue attributable to the invention, before the rate is applied. Failing to apportion is one of the most common reasons damages awards are reduced or vacated on appeal. Reasonable royalty patent damages that survive scrutiny almost always rest on a base the expert can defend as tied specifically to the patented advance.

Apportionment and rate are not independent, either. A rate drawn from a licence that already covers only the patented feature should not be applied to a whole-product base, and vice versa; double-counting value is a classic error opposing experts probe for. The cleanest analyses keep the rate and the base internally consistent, so the two together measure the invention’s contribution once, not twice.

How Large Are Patent Damages in Practice?

Headline verdicts distort perception. According to the 2024 Marcum Patent Litigation Study, the overall median US patent damages award from 2003 to 2022 was about $3.7 million, a figure far below the nine-figure awards that make news. Most cases resolve well below the blockbuster numbers, and reasonable royalties, being tied to a defined base and rate, tend to produce more grounded figures than lost-profits theories.

For a patent owner, that reality argues for building the royalty analysis early and rigorously, because a disciplined, evidence-based number is both more defensible in court and more persuasive in the settlement negotiations where most matters actually end.

Building a Defensible Royalty Analysis

A reasonable royalty that withstands a Daubert challenge and cross-examination shares the same DNA as a credible valuation. It selects a rate from comparable, arm’s-length licences adjusted for scope and term; it apportions to a defensible base; it walks through the Georgia-Pacific factors that actually matter on the facts; and it documents every input to a traceable source.

That is precisely the discipline behind the relief-from-royalty and comparable-benchmarking work in our IP valuation service, and we walk through it end to end in a related IP valuation case study. For the licensing side of the same question, see our guide to patent royalty rates. The through-line is simple: a number is only worth what the evidence and reasoning behind it can defend.

Need a Defensible Royalty or Damages Analysis?

PerspireIP builds royalty and valuation analyses tied to real licence evidence and documented to the standard a court applies. Talk to our team about your matter.

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