Public-evidence forecast

Is it Q-Day?
Not yet.

The answer is not a date. It is an interval — and it moves only when evidence moves it, never when a vendor issues a press release.

No forecast leads this page yet. The current model version is published as a research update — model version #4.

What it does say: 0.3% of simulated futures cross by 2035; 5.1% of simulated futures cross by 2050; 27.7% of simulated futures cross by 2086. The remaining 72.3% never cross inside the model’s horizon, which is why no median is named.

NIST P-256 · forecast interval, P10 to P90 (calendar dates) · model version #4
P10, P50 and P90 dates for the NIST P-256 forecast
P10 (10% of futures cross by) P50 (median estimate) P90 (90% of futures cross by)
2059-10-29 Median unresolved Not defined

The bar ends at the modelled horizon, not at a P90. Percentiles shown as “not defined” fall in the censored tail: too many simulated scenarios never reach a crossing for those percentiles to be estimated, so no upper bound is drawn rather than one being placed at the horizon.

From model version #4, published as a research update. See how this version was produced — its evidence, configuration, code commit and validation.

Independent context

How other institutions frame the quantum threat

These are independent expert and migration outlooks. They use different methodologies and are not inputs to the Q-Day Index.

Expert survey

28–49%
CRQC quite possible within 10 years
51–70%
CRQC likely within 15 years

Survey of 26 experts. Published 9 March 2026.

This is an expert survey, not the Q-Day Index model and not a percentile from our simulation.

Global Risk Institute — Quantum Threat Timeline Report 2025 · checked 10 August 2026

Migration response

2026 → 2030
EU: Member States should start the PQC transition by end-2026; critical infrastructure as soon as possible and no later than end-2030
2028 → 2035
UK NCSC: discovery and planning by 2028, highest-priority migration by 2031, migration complete by 2035

Commission Recommendation (EU) 2024/1101 of 11 April 2024, and NCSC guidance.

Migration deadlines are risk-management timelines, not predictions of the technical date of CRQC/Q-Day.

European Commission and UK NCSC — PQC transition timelines · NCSC guidance · checked 10 August 2026

Different methodologies answer different questions. External outlooks provide context; the Q-Day Index remains a separately versioned, evidence-backed model.

This is a probabilistic model of CRQC capability based on public evidence. Its primary result is a forecast interval built from the percentiles the evidence can resolve. A percentile that does not cross within the model’s horizon is reported as undefined, never estimated, together with the share of scenarios that do not cross. The model is recalculated weekly and does not claim day-level or second-level certainty.

The evidence behind it

Evidence coverage

Approved public evidence currently represented in each model category. These are record counts, not a measure of quality, certainty, importance or completeness.

Approved public evidence records in each model category, with coverage status.
Category Evidence records Status
Hardware 2 Covered
Error correction 1 Covered
Cryptanalysis 1 Covered
Engineering 0 No approved public evidence yet
Strategic momentum 0 No approved public evidence yet
Hidden capability 0 Unknown — no public evidence
Standards 0 No approved public evidence yet
Scientific evidence 0 No approved public evidence yet

Browse and filter all listed evidence, or see the registered sources every category traces back to.