Step 5 Preview vs Seed 2.1 Turbo
Too close to call on our weighted score (Seed 2.1 Turbo 57, Step 5 Preview 57). The right pick depends on what you value most.
StepFunStep 5 Preview
57/100- ECI—
- Price$1.00 / $2.70
- Context1M
ByteDance SeedSeed 2.1 Turbo
57/100- ECI—
- Price$0.445 / $2.23
- Context256K
Add a model
Make it a three-way comparison.
Too close to call
It is close. Our weighted score puts them within a point (Seed 2.1 Turbo 57/100, Step 5 Preview 57/100), so choose by what matters most for your work: Seed 2.1 Turbo on price and Step 5 Preview for long inputs. The score weighs price 50%, inputs & features 30%, context window 20%. None of the shared benchmarks cover every model here yet, so capability is left out of this verdict.
- CapabilityNot enough dataNo independent benchmark covers every model here yet
- Lowest priceSeed 2.1 TurboSeed 2.1 Turbo $0.891 · Step 5 Preview $1.43 per 1M tokens (3:1 blend)
- Longest contextStep 5 PreviewStep 5 Preview 1,000,000 · Seed 2.1 Turbo 256,000 tokens
- Widest inputsSame inputsStep 5 Preview: Text, Images, Video · Seed 2.1 Turbo: Text, Images, Video
- Self-hostingNo open weightsBoth are available only through APIs
| Measure | Weight | Step 5 Preview | Seed 2.1 Turbo |
|---|---|---|---|
| Price | 50% | 43 | 52 |
| Inputs & features | 30% | 80 | 80 |
| Context window | 20% | 60 | 36 |
| Overall | 100% | 57/100 | 57/100 |
Left out because at least one model lacks the data: capability. The remaining weights were rescaled.
Every spec in one table
Highlighted cells lead their row. Dashes mean the data is not published.
| Specification | Step 5 PreviewStepFun | Seed 2.1 TurboByteDance Seed |
|---|---|---|
| Capability | ||
| Capabilities Index (ECI) | — | — |
| ECI rank | — | — |
| Price per million tokens | ||
| Input | $1.00 | $0.445 (best) |
| Output | $2.70 | $2.23 (best) |
| Cached input | $0.05 (best) | $0.089 |
| Blended (3:1) | $1.43 | $0.891 (best) |
| Long-context rate | Same rate | Same rate |
| Price source | Official StepFun (Global) API | Official Volcengine Ark API |
| Limits | ||
| Context window | 1,000,000 tokens (best) | 256,000 tokens |
| Max output | 1,000,000 tokens (best) | 256,000 tokens |
| Inputs and features | ||
| Text | Yes | Yes |
| Images | Yes | Yes |
| PDFs | No | No |
| Audio | No | No |
| Video | Yes | Yes |
| Reasoning | Yeslow · medium · high | Yesminimal · low · medium · high · xhigh · max |
| Tool calling | Yes | Yes |
| Structured output | Yes | Yes |
| Availability | ||
| Weights | Proprietary | Proprietary |
| API model ID | step-5-preview | doubao-seed-2-1-turbo-260628 |
| API providers | 7 (best) | 4 |
| Released | Sep 16, 2026 | Jun 23, 2026 |
| Knowledge cutoff | — | — |
What would a month cost?
Enter your expected volume in millions of tokens. List prices only; caching and batch discounts would lower these.
- Step 5 Preview$15.40
- Seed 2.1 Turbo$8.91
Which should you choose?
Which is better: Step 5 Preview or Seed 2.1 Turbo?
It is close. Our weighted score puts them within a point (Seed 2.1 Turbo 57/100, Step 5 Preview 57/100), so choose by what matters most for your work: Seed 2.1 Turbo on price and Step 5 Preview for long inputs. The score weighs price 50%, inputs & features 30%, context window 20%. None of the shared benchmarks cover every model here yet, so capability is left out of this verdict.
Which is cheaper, Step 5 Preview or Seed 2.1 Turbo?
Seed 2.1 Turbo is cheaper at $0.445 input / $2.23 output per million tokens (official Volcengine Ark API price). Step 5 Preview costs $1.00 input / $2.70 output per million tokens (official StepFun (Global) API price). At a typical mix of three input tokens to one output token, that is $0.891 per million tokens for Seed 2.1 Turbo versus $1.43 for Step 5 Preview (1.6× as much).
Which scores higher on benchmarks?
There is no independent benchmark that covers both models yet. Step 5 Preview has not been scored yet and Seed 2.1 Turbo has not been scored yet.
Which is better for coding?
There are no published SWE-bench Verified results for Step 5 Preview and Seed 2.1 Turbo yet, so there is no like-for-like coding score. Test both on a sample of your own tasks. Both support tool calling for agent workflows.
Which has the bigger context window?
Step 5 Preview has the largest context window at 1,000,000 tokens, against 256,000 for Seed 2.1 Turbo. Maximum output per response: Step 5 Preview up to 1,000,000, Seed 2.1 Turbo up to 256,000 tokens.
Which can read images, PDFs, audio or video?
Step 5 Preview accepts text, images and video; Seed 2.1 Turbo accepts text, images and video. They handle the same number of input types.
Are any of these open source?
No. Step 5 Preview and Seed 2.1 Turbo are proprietary and only available through APIs and apps.
Which is newer?
Step 5 Preview is the newest, released Sep 16, 2026. Seed 2.1 Turbo came out Jun 23, 2026.
How do you decide the winner?
Each model gets a 0–100 score on capability (50%, independent benchmark results); price (25%, blended price per million tokens (3 input : 1 output), log scale); inputs & features (15%, image, PDF, audio and video input, tool calling, structured output and reasoning); context window (10%, maximum tokens per request, log scale). Dimensions missing for any model are dropped and the remaining weights rescaled, so every model is judged on the same evidence. Specs and prices come from public model listings and the labs’ own API pages; capability scores come from independent benchmark runs. Data updated Oct 4, 2026.
