Gemini 3.1 Pro Preview Custom Tools vs GPT-3.5 Turbo 16k

Gemini 3.1 Pro Preview Custom Tools at $2.30 in and $13.80 out and GPT-3.5 Turbo 16k at $3.45 in and $4.60 out — per million tokens, from the same wallet.

Gemini 3.1 Pro Preview Custom Tools

Google

2.3¢

for a client proposal

$2.30 in · $13.80 out / 1M

1.05M context · released 5 months ago

Full page →

GPT-3.5 Turbo 16k

OpenAI

2.1¢

for a client proposal

$3.45 in · $4.60 out / 1M

16K context · released August 2023

Full page →

Asking all both at once — identical prompt, identical context — costs about 4.3¢ for a typical client proposal.

At a glance

Cheapest input: Gemini 3.1 Pro Preview Custom Tools at $2.30 per million tokens.
Cheapest output: GPT-3.5 Turbo 16k at $4.60 per million tokens.
Largest context: Gemini 3.1 Pro Preview Custom Tools 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 3.1 Pro Preview Custom Tools

1.1¢

GPT-3.5 Turbo 16k

0.92¢

Draft a client proposal from notes

5K in · 800 out

Gemini 3.1 Pro Preview Custom Tools

2.3¢

GPT-3.5 Turbo 16k

2.1¢

Context-heavy session (Alyph workspace)

155K in · 4K out

Gemini 3.1 Pro Preview Custom Tools

$0.41

GPT-3.5 Turbo 16k

needs 155K ctx

Analyze a 50-page legal contract

35K in · 1K out

Gemini 3.1 Pro Preview Custom Tools

$0.09

GPT-3.5 Turbo 16k

needs 35K ctx

Large architecture refactor

250K in · 3K out

Gemini 3.1 Pro Preview Custom Tools

$1.21

GPT-3.5 Turbo 16k

needs 250K ctx

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 3.1 Pro Preview Custom Tools

GPT-3.5 Turbo 16k

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

Pricing

Gemini 3.1 Pro Preview Custom Tools

GPT-3.5 Turbo 16k

Input / 1M tokens

$2.30

$3.45

Output / 1M tokens

$13.80

$4.60

Cached input / 1M

$0.230

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Web search

1.6¢ / search

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Specs

Gemini 3.1 Pro Preview Custom Tools

GPT-3.5 Turbo 16k

Provider

Google

OpenAI

Released

5 months ago

August 2023

Context window

1.05M

16K

Max output

66K

Input

Text, Audio, Images, Video, and Files

Text

Output

Text

Reasoning

Shows its thinking

Answers directly

Knowledge cutoff

—

2021-09-30

Try it with real numbers

2K tokens in · 500 tokens out.

Gemini 3.1 Pro Preview Custom Tools

Google

1.1¢

for this task

40% input · 60% output

Full pricing →

GPT-3.5 Turbo 16k

OpenAI

0.92¢

for this task

75% input · 25% output

Full pricing →

All 2, same prompt and context: 2.1¢. That is the entire cost of the comparison.

Your $5 welcome credit covers about 241 of these.

Which should you pick?

For long documents, Gemini 3.1 Pro Preview Custom Tools has the largest context window here — 1.05M tokens.

On price, GPT-3.5 Turbo 16k is the cheapest of the two on a typical task, at about 2.1¢.

For images or files, Gemini 3.1 Pro Preview Custom Tools can read them directly; GPT-3.5 Turbo 16k is text-only.

If you want to watch the model think, Gemini 3.1 Pro Preview Custom Tools shows reasoning; the other answers directly.

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 3.1 Pro Preview Custom Tools pricing →GPT-3.5 Turbo 16k pricing →Add Lyria 3 Clip Preview Add Grok 4.20

Questions, answered

Which is cheaper, Gemini 3.1 Pro Preview Custom Tools or GPT-3.5 Turbo 16k?

On a typical client proposal (5K tokens in, 800 out): GPT-3.5 Turbo 16k at 2.1¢; Gemini 3.1 Pro Preview Custom Tools at 2.3¢. Long prompts can change the order when long-context rates apply.

Which has the largest context window?

Gemini 3.1 Pro Preview Custom Tools — 1.05M tokens, about 1,500 pages.

Can I run Gemini 3.1 Pro Preview Custom Tools and GPT-3.5 Turbo 16k 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 4.3¢ for a typical task.

Ask both at once

Identical prompt, identical context, answers side by side — about 4.3¢ for a typical client proposal. Free to start, with $5 of credit.