DeepSeek V3 vs Mercury 3
Updated October 21, 2026. 4 benchmarks have a result for both. Coding is ranked on the Vibe Coding Index; every other board is shown as published.
Decision reading
Neither model has a coding score yet, so the two cannot be ranked on coding.
DeepSeek V3 has the edge where what matters is Design Arena: websites or Design Arena: UI components, where it leads.
- Shared results
- 4
- DeepSeek V3 only
- 9
- Mercury 3 only
- 0
- Like-for-like categories
- 1 of 9
Shared results can support a head-to-head reading. Results only one model has describe coverage, not superiority.
Which one for your work
Each card is decided by one number both models carry. Where only one has it, the card says so and makes no call.
Coding
Vibe Coding Index, six public coding benchmarks
No call
Neither has a coding score yet.
One side not measured
Web design
Design Arena: websites
Mercury 3
Mercury 3 leads, 1241 against 1120.
Same board, both measured
Long documents
Listed context window
Mercury 3
Mercury 3 takes 1M tokens against 164K.
Listed by OpenRouter
Everyday cost
1K input + 500 output tokens
Mercury 3
DeepSeek V3 $0.0008, Mercury 3 $0.0003 per turn.
List prices
At a glance
- Coding index
- DeepSeek V3 not benchmarked, Mercury 3 not benchmarked.
- Widest category
- Web design, 18.3 points apart on average over 4 shared benchmarks.
- Widest single gap
- Design Arena: UI components: DeepSeek V3 1093 against Mercury 3 1268, 21.9 points apart on a 0 to 100 scale.
- Output price
- DeepSeek V3 $0.9594 against Mercury 3 $0.35 per million output tokens, 2.7x apart.
- Context window
- DeepSeek V3 takes 164K tokens, Mercury 3 1M.
Benchmark by benchmark
First the score: boards each model leads, per category, where both have a result. Then every board, a category to a fold; bars are each result on a 0 to 100 scale, so compare the two in a row, not one row with another.
| Category | DeepSeek V3 | Bars | Mercury 3 | Ties |
|---|---|---|---|---|
| Web design | 0 | 4 | ||
| All shared boards | 0 | 4 |
CodingDirectional onlySix of these boards feed the Vibe Coding Index2 boards, none shared
| Benchmark | DeepSeek V3 | Mercury 3 | Leader |
|---|---|---|---|
| Aider polyglot | 70.2% | Not measured | Only DeepSeek V3 measured |
| SWE-bench Lite | 30.7% | Not measured | Only DeepSeek V3 measured |
| Neither model has a result on the other 36 boards here | |||
IntelligenceNot comparablePublic boards, shown as published, kept out of the index0 boards, none shared
| Benchmark | DeepSeek V3 | Mercury 3 | Leader |
|---|---|---|---|
| Neither model has a result on 2 boards here | |||
Agentic workNot comparablePublic boards, shown as published, kept out of the index0 boards, none shared
| Benchmark | DeepSeek V3 | Mercury 3 | Leader |
|---|---|---|---|
| Neither model has a result on 39 boards here | |||
ReasoningDirectional onlyPublic boards, shown as published, kept out of the index1 board, none shared
| Benchmark | DeepSeek V3 | Mercury 3 | Leader |
|---|---|---|---|
| GPQA Diamond (Epoch AI run) | 71.2% | Not measured | Only DeepSeek V3 measured |
| Neither model has a result on the other 20 boards here | |||
MathDirectional onlyPublic boards, shown as published, kept out of the index1 board, none shared
| Benchmark | DeepSeek V3 | Mercury 3 | Leader |
|---|---|---|---|
| OTIS Mock AIME | 48.9% | Not measured | Only DeepSeek V3 measured |
| Neither model has a result on the other 12 boards here | |||
KnowledgeNot comparablePublic boards, shown as published, kept out of the index0 boards, none shared
| Benchmark | DeepSeek V3 | Mercury 3 | Leader |
|---|---|---|---|
| Neither model has a result on 17 boards here | |||
Web designLike-for-likePublic boards, shown as published, kept out of the index04
| Benchmark | DeepSeek V3 | Mercury 3 | Leader |
|---|---|---|---|
| Design Arena: websites | 1120 | 1241 | Mercury 3 |
| Design Arena: UI components | 1093 | 1268 | Mercury 3 |
| Design Arena: game dev | 1053 | 1215 | Mercury 3 |
| Design Arena: data viz | 1089 | Not measured | Only DeepSeek V3 measured |
| Design Arena: 3D | 1087 | Not measured | Only DeepSeek V3 measured |
| Design Arena: all code categories | 1108 | 1236 | Mercury 3 |
| Design Arena: SVG | 977 | Not measured | Only DeepSeek V3 measured |
| Neither model has a result on the other 2 boards here | |||
GeneralDirectional onlyPublic boards, shown as published, kept out of the index2 boards, none shared
Image generationNot comparablePublic boards, shown as published, kept out of the index0 boards, none shared
| Benchmark | DeepSeek V3 | Mercury 3 | Leader |
|---|---|---|---|
| Neither model has a result on 5 boards here | |||
What each workload costs
Three fixed token mixes at each model's listed price, so per-token rates become a bill.
Chat turn
1K input + 500 output tokens
Mercury 3 costs less
Repository review
50K input + 3K output tokens
Mercury 3 costs less
Agent loop
200K input + 10K output tokens
Mercury 3 costs less
Listed OpenRouter rates, without cache or batch discounts. A workload that does not fit a model's context window would need splitting.
Specification differences
The leading value in a row is marked; a row with a missing value names no leader. Our two rows are marked in red.
| Specification | DeepSeek V3 | Inception Mercury 3 |
|---|---|---|
| Maker | DeepSeek | Inception |
| Weights | Open weights | No public weights listed |
| Released | December 26, 2024 | October 16, 2026 |
| Context window | 164K | 1M |
| Input $/Mtok | $0.2887 | $0.10 |
| Output $/Mtok | $0.9594 | $0.35 |
| Coding index | Not benchmarked | Not benchmarked |
| Independent measurements behind it | 0 | 0 |
| Cost per solved task | Not computable | Not computable |
| Source | OpenRouter listing | OpenRouter listing |
Questions
Is DeepSeek V3 better than Mercury 3 for coding?
Neither model has a coding score yet, so the two cannot be ranked on coding. DeepSeek V3 has the edge where what matters is Design Arena: websites or Design Arena: UI components, where it leads.
Which is cheaper, DeepSeek V3 or Mercury 3?
DeepSeek V3 costs $0.2887 per million input tokens and $0.9594 per million output tokens; Mercury 3 costs $0.10 and $0.35. Cost per solved task is known for neither of them.
Which has the bigger context window, DeepSeek V3 or Mercury 3?
Mercury 3, with 1M tokens against 164K.
How many benchmarks is the DeepSeek V3 vs Mercury 3 comparison based on?
4 benchmarks have a result for both models as of October 21, 2026. DeepSeek V3's coding index rests on 0 independent benchmarks and Mercury 3's on 0. Where only one model has a result, the page says so instead of naming a winner.