Gemini 3.5 Flash vs Grok 4.5

Gemini 3.5 Flash at $1.73 in and $10.35 out and Grok 4.5 at $2.30 in and $6.90 out — per million tokens, from the same wallet.

Gemini 3.5 Flash

Google

1.7¢

for a client proposal

$1.73 in · $10.35 out / 1M

1.05M context · released 3 months ago

Full page →

Grok 4.5

xAI

1.7¢

for a client proposal

$2.30 in · $6.90 out / 1M

500K context · released 1 month ago

Full page →

Asking all both at once — identical prompt, identical context — costs about 3.4¢ for a typical client proposal.

At a glance

Cheapest input: Gemini 3.5 Flash at $1.73 per million tokens.
Cheapest output: Grok 4.5 at $6.90 per million tokens.
Largest context: Gemini 3.5 Flash at 1.05M tokens — about 1,500 pages.

Cost per task

Estimated totals at the rates above. Solid bar is input, lighter bar is output.

Quick code fix

2K in · 500 out

Gemini 3.5 Flash

0.86¢

Grok 4.5

0.8¢

Draft a client proposal from notes

5K in · 800 out

Gemini 3.5 Flash

1.7¢

Grok 4.5

1.7¢

Context-heavy session (Alyph workspace)

155K in · 4K out

Gemini 3.5 Flash

$0.31

Grok 4.5

$0.38

Analyze a 50-page legal contract

35K in · 1K out

Gemini 3.5 Flash

$0.07

Grok 4.5

$0.09

Large architecture refactor

250K in · 3K out

Gemini 3.5 Flash

$0.46

Grok 4.5

$1.19

Long-context rate applied at this input size.

Solid part of each bar is input tokens, the lighter part is output. Models that don’t fit a task are marked instead of priced.

Cost vs Token Amount

Drag the slider to adjust the split between input and output workload.

80% Input20% Output

Gemini 3.5 Flash

Grok 4.5

Adjust the ratio slider to change how output tokens influence the final price for equivalent workloads.

Pricing

Gemini 3.5 Flash

Grok 4.5

Input / 1M tokens

$1.73

$2.30

Output / 1M tokens

$10.35

$6.90

Cached input / 1M

$0.172

$0.345

Web search

1.6¢ / search

0.57¢ / search

Specs

Gemini 3.5 Flash

Grok 4.5

Provider

Google

xAI

Released

3 months ago

1 month ago

Context window

1.05M

500K

Max output

66K

—

Input

Text, Images, Video, Files, and Audio

Text, Images, and Files

Output

Text

Reasoning

Shows its thinking

Knowledge cutoff

2025-01-01

—

Try it with real numbers

2K tokens in · 500 tokens out.

Gemini 3.5 Flash

Google

0.86¢

for this task

40% input · 60% output

Full pricing →

Grok 4.5

xAI

0.8¢

for this task

57% input · 43% output

Full pricing →

All 2, same prompt and context: 1.7¢. That is the entire cost of the comparison.

Your $5 welcome credit covers about 299 of these.

Which should you pick?

For long documents, Gemini 3.5 Flash has the largest context window here — 1.05M tokens.

On price, Gemini 3.5 Flash is the cheapest of the two on a typical task, at about 1.7¢.

Or don’t pick. Send the identical prompt to all both, read the answers side by side, and keep the winner. How to run a fair bake-off →

Gemini 3.5 Flash pricing →Grok 4.5 pricing →Add Lyria 3 Clip Preview Add Grok 4.20

Questions, answered

Which is cheaper, Gemini 3.5 Flash or Grok 4.5?

On a typical client proposal (5K tokens in, 800 out): Gemini 3.5 Flash at 1.7¢; Grok 4.5 at 1.7¢. Long prompts can change the order when long-context rates apply.

Which has the largest context window?

Gemini 3.5 Flash — 1.05M tokens, about 1,500 pages.

Can I run Gemini 3.5 Flash and Grok 4.5 side by side on Alyph?

Yes — that is what Alyph is built for: the identical prompt with identical context to all 2, answers rendered side by side, billed from one wallet. This exact combination costs about 3.4¢ for a typical task.

Ask both at once

Identical prompt, identical context, answers side by side — about 3.4¢ for a typical client proposal. Free to start, with $5 of credit.