Seed 2.1 Turbo vs Gemini 3.8 Flash
Official ByteDance Seed and Google API prices and LMArena scores, checked 2026-10-29. Add up to 2 more models to compare 4.
Seed 2.1 Turbo costs less; quality is n/a.
Seed 2.1 Turbo is 1.5x cheaper on input and output. LMArena has no task both models are ranked on, so quality is n/a here. Gemini 3.8 Flash has the longer context window (1M vs 256K tokens). A medium month (20M input + 5M output tokens) costs $22.50 on Seed 2.1 Turbo and $33.75 on Gemini 3.8 Flash.
- Pick Seed 2.1 Turbo if you want the lower bill ($22.50 vs $33.75 for a medium month).
- Pick Gemini 3.8 Flash if you need the 1M context window or you reuse long prompts (cached input $0.075 vs $0.10).
Medium: 20M input + 5M output tokens a month at list price (short-context rate, no caching or batch discounts).
Marked side is better: lower for prices, higher for context and scores. Bars are scaled to the larger of the two.
| Spec | Seed 2.1 Turbo | Gemini 3.8 Flash |
|---|---|---|
| Price per 1M tokens | ||
| Input | $0.50 | $0.75 |
| Cached input | $0.10 | $0.075 |
| Output | $2.50 | $3.75 |
| Blend 3:1 | $1 | $1.50 |
| Sample month, medium | $22.50 | $33.75 |
| Context | ||
| Context window | 256K tokens | 1M tokens |
| Quality (LMArena, out of 100) | ||
| Coding | Not ranked | 16/100 #25 of 50 |
| Chat | Not ranked | 54/100 #5 of 51 |
| Creative writing | Not ranked | 56/100 #5 of 51 |
| Roleplay and characters | Not ranked | 46/100 #3 of 51 |
| Reasoning and math | Not ranked | 85/100 #3 of 51 |
| Vision | Not ranked | 80/100 #4 of 33 |
| Long documents | Not ranked | Not ranked |
| Cheap bulk and agents | Not ranked | 52/100 #12 of 34 |
| Details | ||
| Provider | ByteDance Seed | |
| API model id | seed-2.1-turbo | gemini-3.8-flash |
| Notes | BytePlus ModelArk price. Prompts up to 256K. | Through Dec 31, 2026. From Jan 1, 2027: $1.50 in, $7.50 out. |
| Sources | ||
| Last checked | 2026-10-29 | 2026-10-29 |
| Official pricing | ByteDance Seed pricing | Google pricing |
Plans from data checked hourly against each vendor's official pricing page. Vendors state limits in different units, so we quote them as published. Team and enterprise plans are per seat.
API prices in USD per 1M tokens from each provider's official pricing page. Blend 3:1 = (3 x input + output) / 4. Sample month = stated input and output tokens at the list price, no caching. Quality: relative score out of 100 on each LMArena leaderboard (100 = top model we price on that board, n/a = not ranked there), data licensed CC BY 4.0. See how we pick.
Where each one ranks on LMArena
Relative score out of 100 on each leaderboard (100 = the top model we price there), with the rank among the models from our API price table that appear on that board.
- Coding (Code Arena): Seed 2.1 Turbo not ranked, Gemini 3.8 Flash #25 of 50 (16/100)
- Chat (Text Arena): Seed 2.1 Turbo not ranked, Gemini 3.8 Flash #5 of 51 (54/100)
- Creative writing (Text Arena creative writing): Seed 2.1 Turbo not ranked, Gemini 3.8 Flash #5 of 51 (56/100)
- Roleplay and characters (Text Arena multi-turn): Seed 2.1 Turbo not ranked, Gemini 3.8 Flash #3 of 51 (46/100)
- Reasoning and math (Text Arena math): Seed 2.1 Turbo not ranked, Gemini 3.8 Flash #3 of 51 (85/100)
- Vision (Vision Arena): Seed 2.1 Turbo not ranked, Gemini 3.8 Flash #4 of 33 (80/100)
- Long documents (Document Arena): Seed 2.1 Turbo not ranked, Gemini 3.8 Flash not ranked
- Cheap bulk and agents (Agent Arena): Seed 2.1 Turbo not ranked, Gemini 3.8 Flash #12 of 34 (52/100)
Pricing details from the official pages
Seed 2.1 Turbo lists $0.50 input, $2.50 output, $0.10 cached input per 1M tokens on ByteDance Seed pricing. Gemini 3.8 Flash lists $0.75 input, $3.75 output, $0.075 cached input per 1M tokens on Google pricing. Prices checked 2026-10-29.
- Seed 2.1 Turbo: BytePlus ModelArk price. Prompts up to 256K.
- Gemini 3.8 Flash: Through Dec 31, 2026. From Jan 1, 2027: $1.50 in, $7.50 out.
Sample monthly bill at list price, no caching: Light (2M input + 0.5M output tokens): $2.25 vs $3.38. Medium (20M input + 5M output tokens): $22.50 vs $33.75. Heavy (200M input + 50M output tokens): $225 vs $337.50.
FAQ
Is Seed 2.1 Turbo cheaper than Gemini 3.8 Flash?
Seed 2.1 Turbo costs $0.50 input and $2.50 output per 1M tokens; Gemini 3.8 Flash costs $0.75 and $3.75. For a medium month (20M input + 5M output tokens) Seed 2.1 Turbo is cheaper: $22.50 vs $33.75.
Which is better for coding, Seed 2.1 Turbo or Gemini 3.8 Flash?
Code Arena score: Seed 2.1 Turbo n/a (not ranked), Gemini 3.8 Flash 16/100. We do not guess missing scores.
Which has the bigger context window?
Seed 2.1 Turbo: 256K tokens. Gemini 3.8 Flash: 1M tokens.
How much do Seed 2.1 Turbo and Gemini 3.8 Flash cost per month?
Light (2M input + 0.5M output tokens): $2.25 vs $3.38. Medium (20M input + 5M output tokens): $22.50 vs $33.75. Heavy (200M input + 50M output tokens): $225 vs $337.50. Pick your own token counts in the plan vs API calculator.
Where do these numbers come from?
Prices come from each provider's official pricing page, checked daily. Quality is the relative score on the LMArena leaderboard dataset, licensed CC BY 4.0. Where a model is not ranked we show n/a.
Sources
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