Grok 4.3 vs Gemini 3.8 Flash
The AIGROW small-business benchmark cannot tell the two apart, so pick on the job: Gemini 3.8 Flash costs less to read long inputs and Grok 4.3 costs less to write long answers. Grok 4.3 passed 16 of 20 tasks and costs $1.25 in and $2.50 out per million tokens; Gemini 3.8 Flash passed 18 and costs $0.75 in and $3.75 out.
AIGROW credit covers Claude Opus 5.5, Claude Fable 5.2, Claude Fable 5.1, GPT-6 Astra, Claude Sonnet 5.5, GPT-6.1 Sol, GPT-6.1 Terra, Grok 4.7 and Gemini 4 Argon. Gemini 4 Argon below list price
$25 a month brings $110 of API credit and cancels any time; $25 once buys $100. US dollars, standard rate, shortest context band. Cost per pass from the AIGROW small-business benchmark.
- Grok 4.3
- $4.10
- Tasks passed
- 16 of 20
- Gemini 3.8 Flash
- $7.17
- Tasks passed
- 18 of 20
AIGROW small-business benchmark, failed runs included.
xAI's low-cost model against Google's mid tier, with cheaper output on the Grok side. Grok 4.3 costs $4.10 per 1,000 passing answers on the AIGROW small-business benchmark, Gemini 3.8 Flash $7.17. 1,000 support replies cost $4.75 on Grok 4.3 and $3.75 on Gemini 3.8 Flash, so Grok 4.3 costs 27% more.
What each one costs
The API price per million tokens and the cheapest app plan with each model, from the makers’ own pages. Each name opens that model’s full price page.
- Grok 4.3
- On the xAI API, Grok 4.3 costs $1.25 per million input tokens and $2.50 per million output tokens. Grok has a free plan and paid plans from $8/mo (Plus); the plan list does not name Grok 4.3. Plan prices read 22 October 2026.
- Gemini 3.8 Flash
- On the Google API, Gemini 3.8 Flash costs $0.75 per million input tokens and $3.75 per million output tokens.
Side by side
Each maker’s published rate for its standard tier. Cached input is what a repeated prompt prefix costs once the provider has stored it.
| Fact | Grok 4.3 | Gemini 3.8 Flash |
|---|---|---|
| Maker | xAI | |
| Tier | Small and fast | Workhorses |
| Input, per M tokens | $1.25 | $0.75 |
| Output, per M tokens | $2.50 | $3.75 |
| Cached input | $0.20 | $0.075 |
| Context window | 1M | 1.05M |
| Released | Not published | 2 Sep 2026 |
| Weights | Closed weights | Closed weights |
What a job costs on each
1,000 runs of each job at the two list prices. The gap moves from job to job because the models price input, output and cached context differently.
| Job | Grok 4.3 | Gemini 3.8 Flash | Cheaper |
|---|---|---|---|
| Support reply3,000 in, 400 out. | $4.75 | $3.75 | Gemini 3.8 Flash, 21% less |
| Document summary25,000 in, 1,000 out. | $33.75 | $22.50 | Gemini 3.8 Flash, 33% less |
| Agent task80,000 in (70,000 cached), 3,000 out. | $34.00 | $24.00 | Gemini 3.8 Flash, 29% less |
The token counts are ours, chosen to look like real work; the prices are the makers’. A model with no published cache price bills the agent task’s repeated context at its full input rate.
The small print
What each base rate leaves out, from the makers’ own pages: surcharges, discounts, promotions and cache pricing.
- Grok 4.3
- Prompts of 200K tokens or more: $2.50 / $5, cached $0.40. Batch 20% off. xAI no longer lists 'fast' variants; this is its low-cost model. Release date not stated on the official pages. xAI’s pricing page
- Gemini 3.8 Flash
- Launch price through 2026-12-31; from 2027-01-01 it becomes $1.50 / $7.50, cached $0.15. Batch and Flex 50% off; Priority $1.35 / $6.75. Cache storage $0.50 per MTok per hour (rising to $1.00). Google’s pricing page
Other comparisons
Every head to head on the list that involves Grok 4.3 or Gemini 3.8 Flash.
Compare Grok 4.3 and Gemini 3.8 Flash with 52 other models
The price list sets every model’s input and output price side by side, with what a support reply, a document summary and an agent task cost on each.
Prices checked 12 November 2026