Explainer Jan 26, 2026
The nines: why gate fidelity matters
99.9% vs 99.99% looks like a rounding error but means 10× fewer mistakes. Error correction only pays off above a threshold near “three nines”; crossing “four nines” buys real headroom.
Quantum Computing Tracked metric More on this
Best 2-qubit gate fidelity
How often a two-qubit operation succeeds. The threshold for practical error correction sits around 99.9% (“three nines”).
99.99%Reached · Oct 2025 99.99%“four nines” — comfortable fault tolerance
View on the tracker - 99.92 % Press · 2025-11
- 99.99 % Press · 2025-10
- 99.5 % Press · 2024-12
- 99.97 % Press · 2024
- 99.9 % Press · 2024
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