Benchmark guide
What the scores actually mean
Every number on this site comes from an evaluation with a specific design, a specific blind spot, and a specific way of being gamed. This is the field guide: what each benchmark measures, where it breaks, and how much weight it deserves when you are choosing a model.
Last reviewed · August 2026
How to read any benchmark score
Three habits will save you from almost every bad model decision. First, ask what the benchmark rewards rather than what it is named after — a "reasoning" benchmark scored by multiple choice partly rewards elimination tactics, and a preference benchmark partly rewards formatting. Second, ask how old it is: the moment a benchmark becomes prestigious, its questions start leaking into training data, and scores rise without capability rising with them. Third, ask who ran it. A lab reporting its own launch numbers chose the prompting, the scaffolding and the retry budget; an independent harness did not.
Then apply the gap rule. Benchmarks with a few hundred items have a noise band of several percentage points. If two models are within about three points of each other on a single eval, treat them as tied and let a second, independent signal break the tie. That is precisely why this site aggregates rather than crowning a winner from one chart — the reconciliation logic is documented on the methodology page.
The benchmarks we track
Human preference, head-to-head
LMArena Elo (Chatbot Arena)
- Measures
- Anonymous humans are shown two model responses to their own prompt and pick the better one. Wins and losses feed an Elo rating, the same system used to rank chess players.
- Scale
- Roughly 1,100–1,700. A 100-point gap means the higher model wins about 64% of pairings; 200 points means roughly 76%.
- Strength
- It is the only widely-cited number driven by real user prompts rather than a fixed question set, so it cannot be memorised in advance, and it captures things no automated eval does — tone, formatting, whether the answer is actually useful.
- Blind spot
- It measures preference, not correctness. Models that write longer, better-formatted, more confident answers win pairings even when they are wrong, and labs now optimise explicitly for that. It also skews toward short, casual prompts because that is what voters type.
- How to use it
- Treat Elo as a floor test for conversational quality. A frontier model that is not near the top of Arena has a real usability problem — but being #1 on Arena alone does not make a model state of the art.
Graduate-level science reasoning
GPQA Diamond
- Measures
- 448 multiple-choice questions in biology, physics and chemistry, written by PhD holders and filtered so that non-expert humans with unrestricted web access still score around 34%. The Diamond subset is the hardest, most heavily validated slice.
- Scale
- Percentage correct. Domain experts score roughly 65–74%. Frontier models now sit in the 70–90% band.
- Strength
- It is genuinely hard, it resists search-engine shortcuts by design, and it separates models that reason from models that pattern-match. It remains one of the cleanest proxies for deep technical competence.
- Blind spot
- Multiple choice allows lucky guessing and rewards elimination strategies. With only 448 items, a few percentage points of difference is inside the noise band. Contamination pressure grows every month it stays popular.
- How to use it
- Use GPQA to compare reasoning tiers, not to split hairs. A 6-point gap is meaningful; a 1-point gap is not.
Real GitHub issues, real repositories
SWE-bench Verified
- Measures
- 500 human-validated issues drawn from real Python open-source projects. The model gets the repository and the issue text, and must produce a patch. It passes only if the project's own hidden tests pass afterwards.
- Scale
- Percentage of issues resolved. Frontier models are now in the 60–85% range; two years ago the state of the art was under 15%.
- Strength
- The pass criterion is objective and unforgeable — either the maintainers' test suite goes green or it does not. It is the closest thing the field has to a measurement of useful engineering work.
- Blind spot
- It is Python-only and skewed toward a handful of large repositories. Scores vary substantially with scaffolding — the agent loop, retry budget and tooling around the model can move results by ten points or more, so numbers from different harnesses are not directly comparable.
- How to use it
- The single most predictive number for 'can this model fix a bug in my codebase'. Always check which harness produced a quoted score. See the live ranking on the coding leaderboard.
Autonomous work in a real shell
Terminal-Bench
- Measures
- The model is dropped into a sandboxed terminal and given a task — compile something, debug a broken environment, wrangle files, recover a failing service — then judged on whether the end state is correct.
- Scale
- Percentage of tasks completed. Scores are much lower than other benchmarks; leaders sit in the 30–60% range.
- Strength
- It tests the whole agentic loop: planning, using tools, reading error output, recovering from its own mistakes, and knowing when to stop. Chat benchmarks miss all of this entirely.
- Blind spot
- It is young, the task set is small, and results are highly sensitive to the harness and time budget. Failures are often environmental rather than cognitive.
- How to use it
- The best available signal for whether a model can be trusted to run unattended. Weight it heavily for agent products, lightly for chat products.
Novel abstract reasoning
ARC-AGI-2
- Measures
- Visual grid puzzles where each task follows a rule the model has never seen. A handful of input/output examples are given; the model must infer the transformation and apply it. Tasks are built so memorisation cannot help.
- Scale
- Percentage solved. Humans solve most tasks; models score in the low single digits up to roughly 30% at large reasoning budgets.
- Strength
- It is the most contamination-resistant benchmark in wide use, because the rules are novel by construction. It measures fluid intelligence rather than retrieved knowledge.
- Blind spot
- The format — coloured grids — is narrow and unlike almost any production workload. High-scoring runs often burn enormous compute per task, so the headline number can be economically meaningless.
- How to use it
- A research signal about generalisation, not a procurement signal. Interesting for the trajectory of the field; rarely decisive for choosing a model.
Multi-language code editing
Aider Polyglot
- Measures
- 225 hard exercises across C++, Go, Java, JavaScript, Python and Rust. The model must edit existing files correctly, using a real diff format, and the result is checked against unit tests.
- Scale
- Percentage of exercises solved, usually reported alongside an edit-format compliance rate.
- Strength
- It measures the unglamorous skill that dominates day-to-day coding: producing a valid edit to existing code without breaking the surrounding file. Being multi-language, it also exposes Python-only overfitting.
- Blind spot
- Exercises are self-contained and small, so it says little about navigating a large unfamiliar codebase.
- How to use it
- Read it together with SWE-bench. A model strong on SWE-bench but weak on Aider usually has a format-compliance problem your tooling will feel immediately.
Contamination-resistant, rotating questions
LiveBench
- Measures
- A broad benchmark covering maths, coding, reasoning, data analysis, language and instruction following, where questions are refreshed regularly from recent sources so they cannot have been in a training set.
- Scale
- 0–100 aggregate across categories, with per-category breakdowns.
- Strength
- The rotation policy directly attacks the biggest problem in benchmarking — contamination — and the category breakdown reveals lopsided models that a single aggregate would hide.
- Blind spot
- Because the question set changes, scores from different periods are not strictly comparable, and the aggregate mixes very different skills into one number.
- How to use it
- A good breadth check. Use the category breakdown rather than the headline figure whenever it is available.
Broad knowledge, harder variant
MMLU-Pro
- Measures
- A rebuilt version of the classic MMLU exam covering 14 subject areas, with ten answer options instead of four and noisy or trivial questions removed.
- Scale
- Percentage correct. Frontier models sit in the 75–90% band.
- Strength
- Wide subject coverage and enough difficulty to remain discriminative after the original MMLU saturated.
- Blind spot
- Still multiple choice, still knowledge-weighted, and heavily contaminated by now. Differences at the top are largely noise.
- How to use it
- A sanity check for breadth of knowledge. Never a tiebreaker between frontier models.
Independently-run composite
Artificial Analysis Intelligence Index
- Measures
- A composite score computed by Artificial Analysis, who run a fixed set of evaluations themselves against production API endpoints and combine the results into one figure, alongside measured price and speed.
- Scale
- Roughly 0–100.
- Strength
- Independently executed under one consistent harness against the endpoint you would actually call — which means it captures quantisation, routing and serving differences that self-reported lab numbers hide.
- Blind spot
- It is a composite, so the weighting is someone else's editorial judgement, and it inherits every weakness of its component evals.
- How to use it
- Excellent as a cross-check against lab-reported figures. If a lab's claim and this index disagree sharply, trust the independently-run number.
Tokens per second, time to first token
Throughput and latency
- Measures
- Output speed measured against live API endpoints: sustained tokens per second once generation starts, and the delay before the first token arrives.
- Scale
- Tokens/second (tens to hundreds) and seconds to first token.
- Strength
- It is a measurement, not an estimate, and it is often the deciding factor for interactive products where a correct answer that arrives too late is a failed answer.
- Blind spot
- It varies by provider, region, load and time of day, and reasoning models emit large volumes of hidden thinking tokens — so raw tokens per second understates how long a response really takes.
- How to use it
- For anything user-facing, weight speed as heavily as quality. For batch work, ignore it and optimise cost per completed task instead.
Which benchmarks should decide your choice?
It depends entirely on the job. If you are shipping a coding assistant, SWE-bench Verified and Aider Polyglot should dominate your decision and Arena Elo should barely register. If you are building an autonomous agent, Terminal-Bench matters more than everything else combined, because a model that cannot recover from its own errors will fail in production regardless of how well it writes. If you are building a consumer chat product, invert it: Arena Elo and latency are your primary axes, since users judge responsiveness and tone long before they audit correctness. For research and analysis work, GPQA and LiveBench carry the most information, and for high-volume batch pipelines the honest metric is cost per completed task — not per token, since reasoning models can emit ten times the tokens for the same visible answer.
The category leaderboards on this site apply exactly that logic with fixed public weights: coding, reasoning, agentic, long context, speed and cost.
The contamination problem
Every fixed benchmark decays. Questions get scraped, discussed, reproduced in tutorials and eventually absorbed into the next pre-training run, so a model can score higher each generation while getting no better at the underlying skill. The field's defences are imperfect but real: rotating question sets (LiveBench), holding out a private split (ARC-AGI), generating novel tasks by construction, and preferring evaluations judged by execution — tests passing, a terminal reaching the right state — rather than by string matching.
Our practical response is to never let one benchmark decide, to weight execution-graded evaluations above multiple-choice ones, and to treat sudden jumps on an old benchmark with suspicion unless an execution-graded benchmark moves with it. The best contamination-proof evaluation, though, is still the oldest one: run the shortlist against your own prompts and see what happens.
Where our numbers come from
Scores shown across the site are aggregated from public leaderboards and published lab results, with the candidate pool and live pricing pulled from the OpenRouter models API. Where a lab has not published a figure, the value is an estimate and is flagged as such rather than presented as measured. Full detail — the sources, the weighting, the guardrails and the refresh cadence — is on the methodology page. If you spot a score that disagrees with its source, please tell us.