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Grok 4.3 vs Gemini 3.8 Flash API Cost

Grok 4.3 at $1.25/$2.50 against Gemini 3.8 Flash at $0.75/$3.75 per million tokens: which wins depends on how much your workload generates.

Updated · By Niraj Kumar · 6 sources

Models

Each request

Count text inCount text in
tokens

System prompt, conversation history, documents and tool definitions are all resent on every call.

tokens

The visible answer.

Count tokens from a prompt or JSON payloadShow

Plain text, OpenAI Chat or Responses JSON, or Anthropic Messages JSON. A final assistant message or a response body counts as output. Counted in your browser; nothing is uploaded.

Loading the tokenizer…

Counts use OpenAI's o200k tokenizer, so they are exact for GPT-6 and GPT-5 models, plus a few tokens of message framing. Other providers' tokenizers count the same text differently and do not publish a conversion factor; Anthropic says Claude models from 4.7 on produce about 30% more tokens than earlier Claude models. For an exact count on another model, paste one of its API responses: the usage it reports is shown above.

tokens

Thinking tokens are billed as output. Leave at 0 for models or settings that do not reason.

Volume

PricePrice

30,000 requests over 30 days.

Discounts

%
0%100%

The share of input that repeats exactly at the start of every request, such as a fixed system prompt. The prompt caching calculator prices cache writes and expiry in detail.

Batch APIBatch API
Cheaper for this workloadGemini 3.8 Flash18% less, saving $26.25 a month
Grok 4.3
$150.00 a month
$0.005 a request · 9th cheapest of 24
Gemini 3.8 Flash
$123.75 a month
$0.00413 a request · 8th cheapest of 24
At 10× the volume
$262.50 a month apart
Cheapest listed model
Claude Haiku 5.5
$16.50 a month
Side by side
MeasureGrok 4.3Gemini 3.8 Flash
Input, per 1M tokens$1.25$0.75
Cache hit, per 1M tokens$0.20$0.075
Output, per 1M tokens$2.50$3.75
Context window1M tokens1.05M tokens
Max outputNot published65.5K tokens
Batch discount20%50%
Long-context surchargeAbove 200K inputNone
Input cost a month$112.50$67.50
Output cost a month$37.50$56.25
Every model on this workload, per month3,000 tokens in, 500 out, 1,000 a day. Hover or focus a row for rates.
  1. 1Claude Haiku 5.5Anthropic$16.50
  2. 2GPT-6 LunaOpenAI$16.50
  3. 3Qwen3.8 FlashAlibaba$20.55
  4. 4GPT-5.6 LunaOpenAI$36.00
  5. 5DeepSeek V4.1 FlashDeepSeek$45.00
  6. 6Qwen3.7 PlusAlibaba$60.00
  7. 7Gemini 3.5 Flash-LiteGoogle$64.50
  8. 8Gemini 3.8 FlashGoogle$123.75
  9. 9Grok 4.3xAI$150.00
  10. 10Claude Haiku 4.5Anthropic$165.00
  11. 11DeepSeek V4 ProDeepSeek$178.20
  12. 12Grok 4.7xAI$270.00
  13. 13Qwen3.8 MaxAlibaba$270.00
  14. 14Claude Sonnet 5.5Anthropic$330.00
  15. 15Claude Sonnet 5Anthropic$330.00
  16. 16GPT-6.1 SolOpenAI$330.00
  17. 17GPT-6 SolOpenAI$330.00
  18. 18GPT-5.6 TerraOpenAI$360.00
  19. 19Gemini 3.1 ProGoogle$360.00
  20. 20Claude Opus 5.5Anthropic$660.00
  21. 21GPT-5.6 SolOpenAI$660.00
  22. 22Claude Opus 5Anthropic$825.00
  23. 23Claude Fable 5.1Anthropic$1,650
  24. 24GPT-6 AstraOpenAI$1,650

How the Grok 4.3 vs Gemini 3.8 Flash API Cost works

cost = (fresh input × input rate + cached input × cache rate + (output + reasoning) × output rate) ÷ 1,000,000

This page uses the same method as the LLM API Cost Calculator, which explains each term and assumption in full.

Worked example

A chat feature sending 3,000 input tokens and getting 500 back, 1,000 times a day, priced on both models with no caching.

  1. 1Grok 4.3: 3,000 × $1.25 + 500 × $2.50, ÷ 1,000,000 = $0.005 a request, $150.00 a month
  2. 2Gemini 3.8 Flash: 3,000 × $0.75 + 500 × $3.75, ÷ 1,000,000 = $0.00413 a request, $123.75 a month
  3. 3Difference: $26.25 a month

Gemini 3.8 Flash is $26.25 a month cheaper for this workload, 18% less.

Frequently asked questions

Which is cheaper, Grok 4.3 or Gemini 3.8 Flash?

At standard list rates, Gemini 3.8 Flash is 17% cheaper than Grok 4.3 on a typical chat request (3,000 tokens in, 500 out); Grok 4.3 is 29% cheaper than Gemini 3.8 Flash on output-heavy generation (500 in, 2,000 out); and Gemini 3.8 Flash is 36% cheaper than Grok 4.3 on a large cached prompt (20,000 in, 90% cached, 500 out). Grok 4.3 charges $1.25 input and $2.50 output per million tokens; Gemini 3.8 Flash charges $0.75 and $3.75.

Is Grok 4.3 or Gemini 3.8 Flash cheaper?

It depends on the mix. Gemini 3.8 Flash has the cheaper input, $0.75 against $1.25, and Grok 4.3 the cheaper output, $2.50 against $3.75, so input-heavy work such as retrieval favours Gemini and generation favours Grok. That holds only until December 31, 2026: Gemini's rates double on January 1, 2027, after which Grok 4.3 is cheaper on both.

Sources

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