GPT-5.6 Luna vs Qwen3 8B vs Grok 4.20

GPT-5.6 Luna at $0.115 in and $0.690 out, Qwen3 8B at $0.135 in and $0.523 out, and Grok 4.20 at $1.44 in and $2.88 out — per million tokens, from the same wallet.

GPT-5.6 Luna

OpenAI

0.11¢

for a client proposal

$0.115 in · $0.690 out / 1M

1.05M context · released 1 month ago

Full page →

Qwen3 8B

Qwen

0.11¢

for a client proposal

$0.135 in · $0.523 out / 1M

131K context · released April 2025

Full page →

Grok 4.20

xAI

0.95¢

for a client proposal

$1.44 in · $2.88 out / 1M

2M context · released 4 months ago

Full page →

Asking all three at once — identical prompt, identical context — costs about 1.2¢ for a typical client proposal.

At a glance

Cheapest input: GPT-5.6 Luna at $0.115 per million tokens.
Cheapest output: Qwen3 8B at $0.523 per million tokens.
Largest context: Grok 4.20 at 2M tokens — about 2,900 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-5.6 Luna

0.06¢

Qwen3 8B

0.05¢

Grok 4.20

0.43¢

Draft a client proposal from notes

5K in · 800 out

GPT-5.6 Luna

0.11¢

Qwen3 8B

0.11¢

Grok 4.20

0.95¢

Context-heavy session (Alyph workspace)

155K in · 4K out

GPT-5.6 Luna

2.1¢

Qwen3 8B

needs 155K ctx

Grok 4.20

$0.23

Analyze a 50-page legal contract

35K in · 1K out

GPT-5.6 Luna

0.47¢

Qwen3 8B

0.52¢

Grok 4.20

$0.05

Large architecture refactor

250K in · 3K out

GPT-5.6 Luna

3.1¢

Qwen3 8B

needs 250K ctx

Grok 4.20

$0.74

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

GPT-5.6 Luna

Qwen3 8B

Grok 4.20

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

Pricing

GPT-5.6 Luna

Qwen3 8B

Grok 4.20

Input / 1M tokens

$0.115

$0.135

$1.44

Output / 1M tokens

$0.690

$0.523

$2.88

Cached input / 1M

$0.011

—

$0.230

Web search

0.57¢ / search

—

0.57¢ / search

Specs

GPT-5.6 Luna

Qwen3 8B

Grok 4.20

Provider

OpenAI

Qwen

xAI

Released

1 month ago

April 2025

4 months ago

Context window

1.05M

131K

Max output

128K

—

Input

Files, Images, and Text

Text

Text, Images, and Files

Output

Text

Reasoning

Shows its thinking

Knowledge cutoff

2026-02-16

2025-03-31

2025-09-01

Try it with real numbers

2K tokens in · 500 tokens out.

GPT-5.6 Luna

OpenAI

0.06¢

for this task

40% input · 60% output

Full pricing →

Qwen3 8B

Qwen

0.05¢

for this task

51% input · 49% output

Full pricing →

Grok 4.20

xAI

0.43¢

for this task

67% input · 33% output

Full pricing →

All 3, same prompt and context: 0.54¢. That is the entire cost of the comparison.

Your $5 welcome credit covers about 922 of these.

Which should you pick?

For long documents, Grok 4.20 has the largest context window here — 2M tokens.

On price, Qwen3 8B is the cheapest of the three on a typical task, at about 0.11¢.

For images or files, GPT-5.6 Luna and Grok 4.20 can read them directly; Qwen3 8B is text-only.

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

GPT-5.6 Luna pricing →Qwen3 8B pricing →Grok 4.20 pricing →Try other combinations →

Questions, answered

Which is cheapest — GPT-5.6 Luna, Qwen3 8B, or Grok 4.20?

On a typical client proposal (5K tokens in, 800 out): Qwen3 8B at 0.11¢; GPT-5.6 Luna at 0.11¢; Grok 4.20 at 0.95¢. Long prompts can change the order when long-context rates apply.

Which has the largest context window?

Grok 4.20 — 2M tokens, about 2,900 pages.

Can I run GPT-5.6 Luna, Qwen3 8B, and Grok 4.20 side by side on Alyph?

Yes — that is what Alyph is built for: the identical prompt with identical context to all 3, answers rendered side by side, billed from one wallet. This exact combination costs about 1.2¢ for a typical task.

Ask all three at once

Identical prompt, identical context, answers side by side — about 1.2¢ for a typical client proposal. Free to start, with $5 of credit.