Compare / Claude Haiku 5.5 vs Mercury 3
Claude Haiku 5.5 vs Mercury 3
Which is cheaper, which is more capable, and which does better at each kind of work, from 51 results on 4 sources that measured both models.
Of the 51 results both models have, the better value on each. Results whose reported ranges overlap are too close to call.
Results as of 20 October 2026 (catalogue release 2026-10-20-96eb40c3ec63).
Claude Haiku 5.5 or Mercury 3? The short answer
They score about the same, so pick Claude Haiku 5.5: it costs 22% less per deck on DeckBench.
- Spring Prompt overall: Claude Haiku 5.5 43, Mercury 3 39 (out of 100; how the score works).
- Claude Haiku 5.5 is cheaper to run: $0.009 against $0.012 per deck on DeckBench (22% less).
- Mercury 3 is newer: released 19 Oct 2026, against 7 Oct 2026 for Claude Haiku 5.5.
- On our own benchmarks, on the results both models have: Claude Haiku 5.5 does better for decks from an analysis and user surveys; Mercury 3 for marketing planning.
Head to head
Every fact side by side
| Claude Haiku 5.5 | Mercury 3 | |
|---|---|---|
| Price per million tokens | $0.10 in · $0.50 out | $0.20 in · $0.70 out |
| Blended (3 in : 1 out) | $0.20 | $0.33 |
| Cheapest host, blended | – | – |
| Cost per deck (DeckBench) | $0.009 | $0.012 |
| Cached input, per million | – | $0.020 cached input |
| Intelligence Index | 43.4 | – |
| Spring Prompt overall | 43 | 39 |
| Output speed, tokens a second | 240 | – |
| Context window | 1,000,000 tokens | 1,000,000 tokens |
| Released | 7 Oct 2026 | 19 Oct 2026 (newer) |
| Weights | Closed | Closed |
| Developer based in | the US | the US |
Prices are the developer's list price where we have read it, otherwise the typical host on OpenRouter; see every model's price. Intelligence and speed from Artificial Analysis.
Which is better for what
Each model's rank among the models on sale today, for each kind of work, from our own benchmarks and licensed sources. Further right is better; the better rank is in green.
Their slides, side by side
The same brief for both: Manchester store investment review for Hearthside Coffee, an invented company. First slide of each deck from DeckBench.
From our research
- AI Checkpoint: Sol’s new fast lane 9 Oct 2026
- Claude Haiku 5.5 Is Far Better Than Haiku 4.5 at a Tenth of the Price. GPT-6 Luna Still Beats It at Business Work. 8 Oct 2026
- How to Test AI Hallucinations in Business Content 20 Oct 2026
- Mercury 3 first look: very fast with thinking off, too slow with it on 20 Oct 2026
Every shared result
Each model's best result on every measure both have, grouped by benchmark, with the setting that produced it. Under each measure, every model that benchmark has measured is a grey tick, best to the right, so you can see where the two sit in the field. The headline measures of each benchmark come first; the rest are under "Show all". Green marks the better value; where a source reports ranges that overlap, neither is marked.
| Measure | Claude Haiku 5.5 | Mercury 3 |
|---|---|---|
| BulletBench measured by Spring Prompt · 3 results | ||
| Cost per game · Bullet 60sUS dollars, lower is better 6 · 7 of 32 measured | $0.0019no reasoning | $0.0020no reasoning |
| Ladder Elo · Bullet 60sladder Elo, higher is better 24 · 15 of 32 measured | 310no reasoning | 491no reasoning |
| Games lost on time · Bullet 60s% of games, lower is better 18 · 1 of 32 measured | 37.5%no reasoning | 0.0%no reasoning |
| DeckBench measured by Spring Prompt · 3 results | ||
| Cost per deckUS dollars, lower is better 3 · 4 of 24 measured | $0.0091 | $0.0116 |
| Deck ratingrating, higher is betterThe rating weighs each win by how strong the other deck was; the win rate counts wins against whichever decks a model happened to meet, so the two can disagree. 11 · 18 of 24 measured | 1,197 | 812 |
| Accurate decks% of tasks, higher is better 14 · 20 of 24 measured | 33.3% | 0.0% |
| ROASBench measured by Spring Prompt · 3 results | ||
| Overall scorescore out of 100, higher is better 22 · 18 of 24 measured | 24.1 | 26.1 |
| Audience scorescore out of 100, higher is better 18 · 21 of 24 measured | 48.4 | 43.2 |
| Business scorescore out of 100, higher is better 20 · 18 of 24 measured | 13.5 | 17.6 |
| SurveyBench measured by Spring Prompt · 3 results | ||
| Analysis ratingrating, higher is betterThe rating weighs each win by how strong the other analysis was; the win rate counts wins against whichever analyses a model happened to meet, so the two can disagree. 4 · 9 of 13 measured | 1,286 | 752 |
| Cost per taskUS dollars, lower is better 2 · 3 of 12 measured | $0.0185 | $0.0216 |
| Analysis scorepoints of 100, higher is better 5 · 12 of 13 measured | 88.4 | 42.2 |
Show all 51 results (39 more)
| Measure | Claude Haiku 5.5 | Mercury 3 |
|---|---|---|
| BulletBench measured by Spring Prompt · 2 results | ||
| Invalid moves · Bullet 60s% of moves, lower is better 1 · 1 of 32 measured | 0.0%no reasoning | 0.0%low reasoning |
| Median move time · Bullet 60smilliseconds, lower is better 24 · 3 of 32 measured | 1.7 sno reasoning | 0.4 sno reasoning |
| DeckBench measured by Spring Prompt · 14 results | ||
| Caveat dropped% of tasks, lower is better 12 · 12 of 24 measured | 16.7% | 16.7% |
| Clean layout% of tasks, higher is better 6 · 6 of 24 measured | 66.7% | 66.7% |
| Design quality% of the maximum, higher is better 14 · 16 of 24 measured | 61.1% | 58.5% |
| Draft figure quoted% of tasks, lower is better 12 · 12 of 24 measured | 33.3% | 33.3% |
| Findings missing% of tasks, lower is better 17 · 17 of 24 measured | 16.7% | 16.7% |
| Head-to-head win rate% of comparisons, higher is betterThe rating weighs each win by how strong the other deck was; the win rate counts wins against whichever decks a model happened to meet, so the two can disagree. 11 · 16 of 24 measured | 65.8% | 44.0% |
| Layout defects% of tasks, lower is better 6 · 6 of 24 measured | 33.3% | 33.3% |
| Misleading metric used% of tasks, lower is better 22 · 22 of 24 measured | 16.7% | 16.7% |
| Presentable decks% of tasks, higher is better 5 · 12 of 24 measured | 33.3% | 0.0% |
| Recommendation late or wrong% of tasks, lower is better 13 · 22 of 24 measured | 33.3% | 83.3% |
| Slides needing work% of tasks, lower is better 2 · 7 of 24 measured | 16.7% | 33.3% |
| Time per deckseconds, lower is better 5 · 9 of 24 measured | 62.1 | 83.3 |
| Unsupported claims% of tasks, lower is better 17 · 11 of 24 measured | 33.3% | 16.7% |
| Unsupported numbers% of tasks, lower is better 20 · 20 of 24 measured | 16.7% | 16.7% |
| ROASBench measured by Spring Prompt · 6 results | ||
| Consistency scorescore out of 100, higher is better 21 · 19 of 24 measured | 10.6 | 15.1 |
| Contribution profitsimulated US dollars, higher is better 20 · 18 of 24 measured | $32,146 | $104,868 |
| Cost of a runUS dollars, lower is better 4 · 6 of 24 measured | $0.0313 | $0.0533 |
| Months over budgetmonths of 12, lower is better 1 · 1 of 24 measured | 0 | 0 |
| Planning scorescore out of 100, higher is better 13 · 23 of 24 measured | 54.8 | 53.8 |
| Return on ad spendprofit per $1 spent, higher is better 20 · 18 of 24 measured | $0.03 | $0.10 |
| SurveyBench measured by Spring Prompt · 17 results | ||
| Head-to-head win rate% of comparisons, higher is betterThe rating weighs each win by how strong the other analysis was; the win rate counts wins against whichever analyses a model happened to meet, so the two can disagree. 4 · 6 of 13 measured | 65.0% | 48.6% |
| Leading or double-barrelled questions% of tasks, lower is better 4 · 8 of 13 measured | 33.3% | 55.6% |
| Mistaken next steps% of tasks, lower is better 5 · 5 of 13 measured | 22.2% | 22.2% |
| Numbers right% of answers, higher is better 1 · 13 of 13 measured | 100.0% | 63.3% |
| Objectives unanswerable% of tasks, lower is better 1 · 1 of 13 measured | 0.0% | 0.0% |
| Precision ignored% of tasks, lower is better 1 · 1 of 13 measured | 0.0% | 0.0% |
| Research scorepoints of 100, higher is better 5 · 11 of 13 measured | 90.2 | 56.8 |
| Sound research% of tasks, higher is better 5 · 6 of 13 measured | 11.1% | 0.0% |
| Stakeholder's view presumed% of tasks, lower is better 1 · 7 of 13 measured | 0.0% | 22.2% |
| Survey plan scorepoints of 100, higher is better 3 · 6 of 13 measured | 94.5 | 90.8 |
| Survey structure% of tasks, lower is better 7 · 7 of 13 measured | 22.2% | 22.2% |
| Time per taskseconds, lower is better 7 · 10 of 12 measured | 147 | 194 |
| Traps handled% of traps, higher is better 4 · 11 of 13 measured | 94.2% | 60.7% |
| Traps missed% of tasks, lower is better 2 · 7 of 13 measured | 22.2% | 88.9% |
| Unsupported findings% of tasks, lower is better 7 · 4 of 13 measured | 77.8% | 44.4% |
| Wrong numbers% of tasks, lower is better 1 · 9 of 13 measured | 0.0% | 44.4% |
| Wrong recommendation% of tasks, lower is better 3 · 12 of 13 measured | 11.1% | 77.8% |
Compare them with other models
- Claude Haiku 5.5 vs DeepSeek-V4.1-FlashFastest with similar intelligence
- Claude Haiku 5.5 vs Claude Opus 5.5Most intelligent available today
- Claude Haiku 5.5 vs Grok 4.7Just above overall
- Claude Haiku 5.5 vs GPT-6 LunaJust below overall
- Mercury 3 vs Claude Opus 5.5Highest-scoring overall available today
- Mercury 3 vs GPT-6 LunaJust above overall
- Mercury 3 vs GLM-5.3Just below overall
Quick answers
Is Claude Haiku 5.5 better than Mercury 3?
They score about the same, so pick Claude Haiku 5.5: it costs 22% less per deck on DeckBench.
Which is cheaper, Claude Haiku 5.5 or Mercury 3?
Claude Haiku 5.5 is cheaper to run: $0.009 against $0.012 per deck on DeckBench (22% less).
Which is better for decks from an analysis, Claude Haiku 5.5 or Mercury 3?
Claude Haiku 5.5 ranks 11 of 24 models on sale for turning a finished analysis into a deck you could present as it is, against 18 for Mercury 3.
Which is better for user surveys, Claude Haiku 5.5 or Mercury 3?
Claude Haiku 5.5 ranks 4 of 13 models on sale for planning a user survey and reading its results without being misled, against 9 for Mercury 3.
Which is better for marketing planning, Claude Haiku 5.5 or Mercury 3?
Mercury 3 ranks 18 of 24 models on sale for planning a year of ad spend without overspending, against 22 for Claude Haiku 5.5.
Which is better for speed under pressure, Claude Haiku 5.5 or Mercury 3?
Mercury 3 ranks 10 of 27 models on sale for good decisions against a real clock (fast chess), against 17 for Claude Haiku 5.5.
Run Claude Haiku 5.5 and Mercury 3 on your own prompt
Benchmarks aren't your data. Try both side by side in the playground, with the cost of every answer.