Model comparison
DeepSeek-V3.1-Terminus vs DeepSeek V4.1 Flash
DeepSeek V4.1 Flash is the stronger model overall, scoring 50.3 to 42.6 on the Noometry Index.
Last verified . 15 shared benchmarks.
DeepSeekSummary
- They share 15 benchmarks with published results for both. DeepSeek-V3.1-Terminus scores higher in 0 categories and DeepSeek V4.1 Flash in 7 categories; 7 gaps are clear of the uncertainty.
- The widest gap is in reasoning, where DeepSeek V4.1 Flash leads 46.2 to 25.7.
- The biggest single-benchmark swing is LMCA: 28.6% for DeepSeek-V3.1-Terminus and 47% for DeepSeek V4.1 Flash.
- DeepSeek V4.1 Flash is cheaper at $0.15 / $0.60 per million input/output tokens, against $0.30 / $1 for DeepSeek-V3.1-Terminus.
- DeepSeek V4.1 Flash accepts more context: 1M tokens versus 164K.
Side by side
| DeepSeek-V3.1-Terminus | DeepSeek V4.1 Flash | |
|---|---|---|
| Provider | DeepSeek | DeepSeek |
| Noometry Index | 42.6 | 50.3 |
| Released | 2025-09-22 | 2026-09-09 |
| Weights | Open | Open |
| Context window | 164K | 1M |
| Max output | 66K | 393K |
| Input $ / M tokens | $0.30 | $0.15 |
| Output $ / M tokens | $1 | $0.60 |
| Results tracked | 16 | 25 |
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Category by category
Coding DeepSeek V4.1 Flash leads
DeepSeek-V3.1-Terminus: 41.5 (#114), DeepSeek V4.1 Flash: 52.8 (#29)
| Benchmark | DeepSeek-V3.1-Terminus | DeepSeek V4.1 Flash |
|---|---|---|
| SciCode | 40.6% | 51.9% |
| LMArena Coding | 1426 | 1511 |
| ALE-Bench | 745.17 | 1,092 |
| LMArena WebDev | — | 1620 |
Reasoning DeepSeek V4.1 Flash leads
DeepSeek-V3.1-Terminus: 25.7 (#126), DeepSeek V4.1 Flash: 46.2 (#39)
| Benchmark | DeepSeek-V3.1-Terminus | DeepSeek V4.1 Flash |
|---|---|---|
| CritPt | 1.7% | 14.3% |
| LMArena Hard Prompts | 1427 | 1485 |
| DTBench | 81.3% | 89.9% |
| LMCA | 28.6% | 47% |
| Kagi LLM Benchmark | 57.4% | — |
| NYT Connections (extended) | — | 89.6% |
| Surface Evolver Bench | — | 46.3% |
| Epoch Capabilities Index | — | 155.01 |
Math DeepSeek V4.1 Flash leads
DeepSeek-V3.1-Terminus: 35.7 (#138), DeepSeek V4.1 Flash: 48.4 (#52)
| Benchmark | DeepSeek-V3.1-Terminus | DeepSeek V4.1 Flash |
|---|---|---|
| LMArena Math | 1402 | 1493 |
| ProofBench | — | 54% |
Knowledge Not comparable
DeepSeek-V3.1-Terminus: —, DeepSeek V4.1 Flash: 41.6 (#97)
| Benchmark | DeepSeek-V3.1-Terminus | DeepSeek V4.1 Flash |
|---|---|---|
| LMArena Expert | — | 1505 |
Multilingual DeepSeek V4.1 Flash leads
DeepSeek-V3.1-Terminus: 52.3 (#87), DeepSeek V4.1 Flash: 55.5 (#29)
| Benchmark | DeepSeek-V3.1-Terminus | DeepSeek V4.1 Flash |
|---|---|---|
| LMArena Non-English | 1407 | 1452 |
| LMArena Russian | 1434 | 1473 |
| LMArena Chinese | — | 1506 |
| LMArena French | — | 1448 |
| LMArena Spanish | — | 1499 |
Instruction Following DeepSeek V4.1 Flash leads
DeepSeek-V3.1-Terminus: 74.4 (#96), DeepSeek V4.1 Flash: 77.6 (#24)
| Benchmark | DeepSeek-V3.1-Terminus | DeepSeek V4.1 Flash |
|---|---|---|
| LMArena Instruction Following | 1406 | 1475 |
Long Context DeepSeek V4.1 Flash leads
DeepSeek-V3.1-Terminus: 43.5 (#88), DeepSeek V4.1 Flash: 45.2 (#46)
| Benchmark | DeepSeek-V3.1-Terminus | DeepSeek V4.1 Flash |
|---|---|---|
| LMArena Longer Query | 1426 | 1476 |
Writing & Preference DeepSeek V4.1 Flash leads
DeepSeek-V3.1-Terminus: 61.3 (#87), DeepSeek V4.1 Flash: 65.8 (#43)
| Benchmark | DeepSeek-V3.1-Terminus | DeepSeek V4.1 Flash |
|---|---|---|
| LMArena Text | 1420 | 1465 |
| LMArena Creative Writing | 1404 | 1436 |
| LMArena Multi-Turn | 1411 | 1460 |
| EQ-Bench Creative Writing | — | 1540 |
Frequently asked questions
Is DeepSeek-V3.1-Terminus better than DeepSeek V4.1 Flash?
DeepSeek V4.1 Flash is the stronger model overall, scoring 50.3 to 42.6 on the Noometry Index.
Which is cheaper, DeepSeek-V3.1-Terminus or DeepSeek V4.1 Flash?
DeepSeek V4.1 Flash is cheaper. It lists at $0.15 per million input tokens and $0.60 per million output tokens; DeepSeek-V3.1-Terminus lists at $0.30 and $1.
Is DeepSeek-V3.1-Terminus or DeepSeek V4.1 Flash better for coding?
DeepSeek V4.1 Flash scores higher on coding benchmarks: 52.8 versus 41.5 in the Noometry coding category.
Which has the bigger context window?
DeepSeek V4.1 Flash does, with 1M tokens against 164K.
How many benchmarks do DeepSeek-V3.1-Terminus and DeepSeek V4.1 Flash share?
15 benchmarks have published results for both models. DeepSeek-V3.1-Terminus has 16 scored results on Noometry and DeepSeek V4.1 Flash has 25.