Every other tool answers "run my method." Atlas also answers the money question: what would this circuit cost on a real QPU, and what does the classical route cost instead? The number is built from a formula you can see, with assumptions you can edit — labeled published / measured / derived, never a black box.
deploy/app/economics.pybenchmarks/spend_frontier/ in the repo · pricing snapshot 2026-06-25 · counterfactual framing applies to every QPU figure.multiplier_n45 (QASMBench, 45 qubits) carries #T = 2,646 — on paper, a hard circuit. Atlas routes it CPU: the engine runs it at MPS bond dimension 1, measured classical cost $0.000177/eval. The same job on a QPU: $17,560.86. Magic ≠ hardness.
mqt_randomcircuit_n24 (MQT Bench, 24 qubits): Atlas's own estimators hit their budget — yet the TENSOR route still prices the classical side at $3.91e-4/eval (modeled contraction cost at HPC rates) vs $10,853.50 on a QPU.
sycamore_rcs_53q_depth20 (Sycamore-scale RCS): route ESCALATE — no classical price exists in Atlas's measured reach. The QPU side prices at $1,381.34/eval; the 127-qubit kicked-Ising utility circuit at $4,504. Atlas escalates them instead of pretending.
Everything above is computed, not asserted. This section is the full derivation: shots from precision, mitigation overhead, per-device calibration, vendor billing models, the measured classical side, and where this sits against other cost tools. Every term labeled published / measured / derived.
$0.30 task + 10,060 shots × $0.08/shot, published Braket pricing. At research-grade precision (ε=3e-3, ~112k shots) the same job is ≈ $8,900. Open the panel and recompute — that is the point. See also the corpus-wide exhibit above — the $805-class job appears there as mqt_cdkm_ripple_carry_adder_n18 at $801.26/eval.
To pin an expectation value to additive error ε you need shots that beat shot-noise (error ~ 1/√N):
N_base = ⌈ 1 / ε² ⌉ε=1e-1 → 100 · ε=1e-2 → 10,000 · ε=3e-3 → ~111,111. derived (textbook shot-noise). Vendor floors apply (e.g. IonQ error-mitigation minimum 2,500 shots).
Real hardware is noisy, so a usable expectation value needs error mitigation, whose sample overhead grows exponentially with circuit volume × noise (probabilistic error cancellation):
N = N_base · γ², γ² = e^(4·λ), λ = ε_g · n₂qpublished bound — Quek/Eisert arXiv:2210.11505, Takagi arXiv:2109.04457. n₂q = two-qubit gate count, ε_g = per-gate error (next section).
ε_g or the mitigation model move the QPU cost by orders of magnitude. That is exactly why Atlas exposes ε_g and the formula as editable and sourced — the honest answer to "why this model?" is "PEC, published, and you can swap it," not "trust us." We label it published, never measured.The exponent rides on ε_g, so Atlas uses per-device values, not one generic number:
| Device | ε_g (2-qubit) | Provenance |
|---|---|---|
| IBM (Heron r2) | 2.0e-3 | measured — Atlas's own ibm_kingston RB (2.02e-3 isolated; 3.42e-3 EPLG layered) |
| Rigetti | 5.0e-3 | published — 99.5% 2q fidelity |
| IQM (Garnet/Emerald) | 5.0e-3 | published — 99.51% |
| IonQ (Forte/Aria) | 3e-4 | vendor-claimed — no hard public 2q figure; optimistic, flagged uncertain |
The IBM number is measured on our own hardware runs — and that calibration data ships in the repo (kingston_calibration.json). Note: IBM Quantum device data (job IDs, calibration, results) is IBM's data, used under IBM Quantum's terms — NOT licensed under Apache-2.0; only Atlas's own code/corpus/scripts are. The rest are published/claimed and editable.
Most naïve estimators invent a $/shot for IBM. IBM doesn't bill per shot — it bills per minute of QPU time. Atlas branches:
per-shot (AWS Braket): cost = task_fee + N · per_shot per-minute (IBM): cost = runtime_min · rate_per_minpublished tariffs — AWS Braket (IonQ $0.08/shot + $0.30/task; Rigetti $0.000425; IQM/AQT/QuEra) · IBM plans (Open free · Pay-As-You-Go $96/min · Flex $72/min · Premium $48/min). Verify: AWS Braket pricing · IBM Quantum plans.
The whole verdict is a comparison, so the classical cost is measured, not guessed: Atlas times the real MPS/tensor contraction (quimb) for the circuit and prices the wall-clock at a cloud-CPU rate. The reference machine is a dev Apple M4 (24 GB) — see the per-estimator ceilings on the Evidence page.
A laptop that settles the circuit in milliseconds at near-zero cost, versus the QPU job above, is the "don't spend" verdict in dollars.
IonQ Forte, a small tractable circuit a laptop runs in ms:
| Precision ε | Shots (incl. mitigation) | QPU $/job |
|---|---|---|
| 1e-1 / 3e-2 | 2,500 (vendor floor) | $200.30 |
| 1e-2 (casual) | ~10,060 | ≈ $805 |
| 3e-3 (research-grade) | ~111,781 | ≈ $8,900 |
Every row is recomputable from §1–4 with the published pricing; the panel lets you change vendor, ε and campaign size and watch the number move.
Vendor pricing tools — AWS Braket, IBM Quantum, IonQ — price their own hardware: useful once you've decided to run, silent on whether you should. Fault-tolerant resource estimators — Microsoft's Azure Quantum Resource Estimator and BenchQ — answer a different, future question: the physical qubits and runtime a large algorithm would need on a fault-tolerant machine that does not yet exist. Work on quantum economic advantage and the QEA online calculator estimate theoretical crossover points by algorithm class, not the measured cost of your circuit today. Atlas fills the near-term gap between them: it triages whether this specific circuit is classically simulable, measures what running it classically actually costs, and sets that against published QPU pricing — one auditable spend-or-don't-spend verdict for the hardware you can rent right now. We are not aware of another tool that combines all three.
Pricing shown is a dated snapshot under declared assumptions; classical time is measured, QPU cost is published pricing; decision support, not financial advice.
ε_g from our own QPU runs); (3) per-shot-vs-per-minute modeled correctly; (4) full auditability — every term labeled and sourced. The page you are reading is the moat: a cost number you can recompute, versus a black-box calculator you can't.