GPT-5.4 vs gpt-oss-20b

GPT-5.4 at $2.88 in and $17.25 out and gpt-oss-20b at $0.035 in and $0.149 out — per million tokens, from the same wallet.

GPT-5.4

OpenAI

2.8¢

for a client proposal

$2.88 in · $17.25 out / 1M

1.05M context · released 6 months ago

Full page →

gpt-oss-20b

OpenAI

0.03¢

for a client proposal

$0.035 in · $0.149 out / 1M

131K context · released August 2025

Full page →

Asking all both at once — identical prompt, identical context — costs about 2.8¢ for a typical client proposal.

At a glance

Cheapest input: gpt-oss-20b at $0.035 per million tokens.
Cheapest output: gpt-oss-20b at $0.149 per million tokens.
Largest context: GPT-5.4 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

GPT-5.4

1.4¢

gpt-oss-20b

0.01¢

Draft a client proposal from notes

5K in · 800 out

GPT-5.4

2.8¢

gpt-oss-20b

0.03¢

Context-heavy session (Alyph workspace)

155K in · 4K out

GPT-5.4

$0.51

gpt-oss-20b

needs 155K ctx

Analyze a 50-page legal contract

35K in · 1K out

GPT-5.4

$0.12

gpt-oss-20b

0.14¢

Large architecture refactor

250K in · 3K out

GPT-5.4

$0.77

gpt-oss-20b

needs 250K ctx

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

GPT-5.4

gpt-oss-20b

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

Pricing

GPT-5.4

gpt-oss-20b

Input / 1M tokens

$2.88

$0.035

Output / 1M tokens

$17.25

$0.149

Cached input / 1M

$0.287

$0.035

Web search

1.1¢ / search

—

Specs

GPT-5.4

gpt-oss-20b

Provider

OpenAI

Released

6 months ago

August 2025

Context window

1.05M

131K

Max output

128K

131K

Input

Text, Images, and Files

Text

Output

Text

Reasoning

Shows its thinking

Knowledge cutoff

—

2024-06-30

Try it with real numbers

2K tokens in · 500 tokens out.

GPT-5.4

OpenAI

1.4¢

for this task

40% input · 60% output

Full pricing →

gpt-oss-20b

OpenAI

0.01¢

for this task

48% input · 52% output

Full pricing →

All 2, same prompt and context: 1.5¢. That is the entire cost of the comparison.

Your $5 welcome credit covers about 344 of these.

Which should you pick?

For long documents, GPT-5.4 has the largest context window here — 1.05M tokens.

On price, gpt-oss-20b is the cheapest of the two on a typical task, at about 0.03¢.

For images or files, GPT-5.4 can read them directly; gpt-oss-20b is text-only.

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 →

GPT-5.4 pricing →gpt-oss-20b pricing →Add Lyria 3 Clip Preview Add Grok 4.20

Questions, answered

Which is cheaper, GPT-5.4 or gpt-oss-20b?

On a typical client proposal (5K tokens in, 800 out): gpt-oss-20b at 0.03¢; GPT-5.4 at 2.8¢. Long prompts can change the order when long-context rates apply.

Which has the largest context window?

GPT-5.4 — 1.05M tokens, about 1,500 pages.

Can I run GPT-5.4 and gpt-oss-20b 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 2.8¢ for a typical task.

Ask both at once

Identical prompt, identical context, answers side by side — about 2.8¢ for a typical client proposal. Free to start, with $5 of credit.