Seed 1.6 Flash vs Mercury 3
Seed 1.6 Flash and Mercury 3 cost about the same per output token ($0.30 vs $0.35 per million). Updated October 23, 2026; no benchmark has tested both models yet.
- Coding
- No data
- Overall
- No data
- Output $/M
- $0.30
- Coding
- 29.3
- Overall
- No data
- Output $/M
- $0.35
Seed 1.6 Flash or Mercury 3: which to pick
Only Mercury 3 has a coding score, 29.3 on the Vibe Coding Index; Seed 1.6 Flash has none, so the two cannot be ranked on coding.
Pick Seed 1.6 Flash for output tokens 1.2x cheaper ($0.30 vs $0.35 per million).
No benchmark has tested both yet. Seed 1.6 Flash has none yet; Mercury 3 on Terminal-Bench 4 (Vals AI), Vibe Code Bench (Vals AI) and Tax Agent Bench (Vals AI). Compare them on price and context instead.
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
Only Mercury 3 has a coding score, so no call is made.
One side not measured
Web design
Design Arena: websites
No call
Only Mercury 3 has a Design Arena: websites result, 1226.
Directional only
General
Vals Index
No call
Only Mercury 3 has a Vals Index result, 43.7%.
Directional only
Long documents
Listed context window
Mercury 3
Mercury 3 takes 1M tokens against 262K.
Listed by OpenRouter
Everyday cost
1K input + 500 output tokens
Seed 1.6 Flash
Seed 1.6 Flash $0.0002, Mercury 3 $0.0003 per turn.
List prices
At a glance
- Coding index
- Seed 1.6 Flash not benchmarked, Mercury 3 29.3 from 2 benchmarks.
- Widest category
- None yet: no category has been tested on both models.
- Widest single gap
- None yet: no benchmark has tested both models.
- Output price
- Seed 1.6 Flash $0.30 against Mercury 3 $0.35 per million output tokens, 1.2x apart.
- Context window
- Seed 1.6 Flash takes 262K tokens, Mercury 3 1M.
Benchmark by benchmark
Every board either model has a result on, a category to a fold; bars are each result on a 0 to 100 scale. Only one model is measured on each, so no row names a leader.
CodingDirectional onlySix of these boards feed the Vibe Coding Index2 boards measured
| Benchmark | Seed 1.6 Flash | Mercury 3 | Leader |
|---|---|---|---|
| Terminal-Bench 4 (Vals AI) | Not measured | 3.0% | Only Mercury 3 measured |
| Vibe Code Bench (Vals AI) | Not measured | 60.9% | Only Mercury 3 measured |
| Neither model has a result on the other 41 boards here | |||
Agentic workDirectional onlyPublic boards, shown as published, kept out of the index3 boards measured
| Benchmark | Seed 1.6 Flash | Mercury 3 | Leader |
|---|---|---|---|
| Tax Agent Bench (Vals AI) | Not measured | 18.2% | Only Mercury 3 measured |
| Legal Research Bench (Vals AI) | Not measured | 28.9% | Only Mercury 3 measured |
| Harvey's Legal Agent Benchmark (Vals AI) | Not measured | 5.0% | Only Mercury 3 measured |
| Neither model has a result on the other 39 boards here | |||
Web designDirectional onlyPublic boards, shown as published, kept out of the index6 boards measured
| Benchmark | Seed 1.6 Flash | Mercury 3 | Leader |
|---|---|---|---|
| Design Arena: websites | Not measured | 1226 | Only Mercury 3 measured |
| Design Arena: UI components | Not measured | 1247 | Only Mercury 3 measured |
| Design Arena: game dev | Not measured | 1227 | Only Mercury 3 measured |
| Design Arena: data viz | Not measured | 1201 | Only Mercury 3 measured |
| Design Arena: all code categories | Not measured | 1231 | Only Mercury 3 measured |
| Design Arena: SVG | Not measured | 1174 | Only Mercury 3 measured |
| Neither model has a result on the other 3 boards here | |||
GeneralDirectional onlyPublic boards, shown as published, kept out of the index1 board measured
| Benchmark | Seed 1.6 Flash | Mercury 3 | Leader |
|---|---|---|---|
| Vals Index | Not measured | 43.7% | Only Mercury 3 measured |
| Neither model has a result on the other 47 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
Seed 1.6 Flash costs less
Repository review
50K input + 3K output tokens
Seed 1.6 Flash costs less
Agent loop
200K input + 10K output tokens
Seed 1.6 Flash 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 | ByteDance Seed Seed 1.6 Flash | Inception Mercury 3 |
|---|---|---|
| Maker | ByteDance Seed | Inception |
| Weights | No public weights listed | No public weights listed |
| Released | December 23, 2025 | October 16, 2026 |
| Context window | 262K | 1M |
| Input $/Mtok | $0.075 | $0.10 |
| Output $/Mtok | $0.30 | $0.35 |
| Coding index | Not benchmarked | 29.3 |
| Independent measurements behind it | 0 | 2 |
| Cost per solved task | Not computable | Not computable |
| Source | OpenRouter listing | OpenRouter listing |
Questions
Is Seed 1.6 Flash better than Mercury 3 for coding?
Only Mercury 3 has a coding score, 29.3 on the Vibe Coding Index; Seed 1.6 Flash has none, so the two cannot be ranked on coding. Pick Seed 1.6 Flash for output tokens 1.2x cheaper ($0.30 vs $0.35 per million).
Which is cheaper, Seed 1.6 Flash or Mercury 3?
Seed 1.6 Flash costs $0.075 per million input tokens and $0.30 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, Seed 1.6 Flash or Mercury 3?
Mercury 3, with 1M tokens against 262K.
Has any benchmark tested both Seed 1.6 Flash and Mercury 3?
No benchmark has tested both yet. Seed 1.6 Flash has none yet; Mercury 3 on Terminal-Bench 4 (Vals AI), Vibe Code Bench (Vals AI) and Tax Agent Bench (Vals AI). Compare them on price and context instead. Data as of October 23, 2026.