Why do quantum market size estimates differ so much?
Published estimates for 2030 range from about $4 billion to more than $20 billion because they measure different layers. Vendor-revenue studies count what quantum companies sell. Economic-impact studies count supply-chain and employment effects. End-use studies count value gained by customers, which can be 10 to 50 times larger. Base years, forecast years, and scope differ too. As of Q3 2026.
Three layers, three answers
Published estimates disagree because they measure three different economic layers, and almost none of them say which one they are using.
Layer one is vendor revenue: what quantum companies are paid. Estimates for 2030 sit between about $4 billion and $20 billion. Layer two is economic impact: the supply chain, employment, and GDP effects that follow from that spending. Layer three is end-use value: the productivity and optimization gains customers capture, which published work puts in the hundreds of billions by 2040.
A tenfold gap between two headline numbers usually means they are measuring different layers, not that one of them is wrong.
Base year and forecast year
Two forecasts with the same growth rate diverge if they start from different places. MarketsandMarkets starts from $3.52 billion in 2025. Grand View Research starts from $1.42 billion in 2024. The higher base carries through every year of the projection.
Forecast end years range from 2030 to 2046 across the published set. A 20-year horizon at 27 percent growth produces a number that cannot be compared with a five-year horizon at 30 percent.
Scope: computing only or all of quantum
Some estimates cover quantum computing. Others cover all quantum technologies, adding sensing, networking, and security. Yole's $17.4 billion by 2035 is a total-quantum figure. TQI's $15.2 billion by 2035 covers computing alone. The two are closer than they look once scope is matched.
How the published estimates line up
| Publisher | Base year and value | Forecast | CAGR | Layer |
|---|---|---|---|---|
| MarketsandMarkets | 2025, $3.52B | $20.20B by 2030 | 41.8% | Vendor revenue |
| Grand View Research | 2024, $1.42B | $4.24B by 2030 | 20.5% | Vendor revenue |
| Fortune Business Insights | 2025, $1.53B | $18.33B by 2034 | 31.6% | Vendor revenue |
| Precedence Research | 2025, $1.44B | $19.44B by 2035 | 29.7% | Vendor revenue |
7 more rows in the dataset
Open the Quantum Market Sizing Dataset →How to compare estimates like for like
Four questions settle most disagreements. Which layer does the number measure? What is the base year and the base value? Does the scope cover computing only or all quantum technologies? Was the estimate built bottom up from company revenue, or top down from an assumed share of an adjacent market?
TQI's model records the answer to all four for its own figures and for every external estimate it triangulates against, which is why the base case sits inside the published range rather than at either edge.
Frequently asked
Use vendor revenue if you sell quantum products or services. Use end-use value if you are estimating what your organization could gain from adopting them. Never add the two.
They usually report value at stake for end users across industries over long horizons, which is a different question from vendor sales.
Most are internally consistent. The error is comparing figures from different layers, base years, or scopes as if they measured the same thing.
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