What is the difference between GPT-5.6 Luna and Mercury?

GPT-5.6 Luna is developed by OpenAI while Mercury is developed by Inception. GPT-5.6 Luna has a 1.1M token context window vs Mercury's 32K. You can compare their actual outputs across 54 challenges on Rival to see how they differ in practice.

Which is better, GPT-5.6 Luna or Mercury?

It depends on your use case. GPT-5.6 Luna and Mercury each have strengths in different areas. Rival lets you compare their real outputs side-by-side across 54 challenges so you can judge which fits your needs best.

How much does GPT-5.6 Luna cost compared to Mercury?

GPT-5.6 Luna costs $1/M input tokens and Mercury costs $10/M input tokens. GPT-5.6 Luna is $9.00/M cheaper per input. Check their side-by-side outputs on Rival to see if the price difference is justified by quality.

How can I compare GPT-5.6 Luna and Mercury on Rival?

This page shows a side-by-side comparison of GPT-5.6 Luna and Mercury across shared challenges. You can vote on which model produced the better output in a blind duel. Browsing and voting are free. No account is needed to look; signing in only saves your votes and likes.

What is the difference between GPT-5.6 Luna and Mercury?

GPT-5.6 Luna is developed by OpenAI while Mercury is developed by Inception. GPT-5.6 Luna has a 1.1M token context window vs Mercury's 32K. You can compare their actual outputs across 54 challenges on Rival to see how they differ in practice.

Which is better, GPT-5.6 Luna or Mercury?

It depends on your use case. GPT-5.6 Luna and Mercury each have strengths in different areas. Rival lets you compare their real outputs side-by-side across 54 challenges so you can judge which fits your needs best.

How much does GPT-5.6 Luna cost compared to Mercury?

GPT-5.6 Luna costs $1/M input tokens and Mercury costs $10/M input tokens. GPT-5.6 Luna is $9.00/M cheaper per input. Check their side-by-side outputs on Rival to see if the price difference is justified by quality.

How can I compare GPT-5.6 Luna and Mercury on Rival?

This page shows a side-by-side comparison of GPT-5.6 Luna and Mercury across shared challenges. You can vote on which model produced the better output in a blind duel. Browsing and voting are free. No account is needed to look; signing in only saves your votes and likes.

GPT-5.6 Luna vs Mercury: Which Is Better?

Updated Jul 2026

Our Verdict

GPT-5.6 Luna

MercuryRunner-up

No community votes yet. On paper, GPT-5.6 Luna has the edge — newer, bigger context window, major provider backing.

Too close to call

What do GPT-5.6 Luna and Mercury say about your brand?

10 models, one question, verbatim receipts.

or peek at a demo: Notion Linear Vercel

API pricing

Cost per 1M tokens

GPT-5.6 Luna

Input

$1.00

10× cheaper

Output

$6.00

1.7× cheaper

Mercury

Input

$10.00

Output

$10.00

GPT-5.6 Luna is cheaper on both — 10× input, 1.7× output

Writing DNA

Style Comparison

Similarity

53%

Mercury uses 4.3x more emoji

GPT-5.6 Luna

Mercury

59%Vocabulary55%

19wSentence Length40w

0.84Hedging0.39

2.7Bold4.9

4.5Lists3.8

0.00Emoji0.04

1.20Headings1.04

0.10Transitions0.03

Based on 27 + 17 text responses

Research

What we learned reading every model

FAQ

Common questions

Keep exploring

More comparisons

Mercury vs MiniMax M3New provider

Mercury vs Ox AlphaNew provider

Mercury vs Claude Opus 4New provider

Updated Jul 2026

Our Verdict

GPT-5.6 Luna

MercuryRunner-up

No community votes yet. On paper, GPT-5.6 Luna has the edge — newer, bigger context window, major provider backing.

Too close to call

What do GPT-5.6 Luna and Mercury say about your brand?

10 models, one question, verbatim receipts.

or peek at a demo: Notion Linear Vercel

API pricing

Cost per 1M tokens

GPT-5.6 Luna

Input

$1.00

10× cheaper

Output

$6.00

1.7× cheaper

Mercury

Input

$10.00

Output

$10.00

GPT-5.6 Luna is cheaper on both — 10× input, 1.7× output

Writing DNA

Style Comparison

Similarity

53%

Mercury uses 4.3x more emoji

GPT-5.6 Luna

Mercury

59%Vocabulary55%

19wSentence Length40w

0.84Hedging0.39

2.7Bold4.9

4.5Lists3.8

0.00Emoji0.04

1.20Headings1.04

0.10Transitions0.03

Based on 27 + 17 text responses

Research

What we learned reading every model

FAQ

Common questions

Keep exploring

More comparisons

Mercury vs MiniMax M3New provider

Mercury vs Ox AlphaNew provider

Mercury vs Claude Opus 4New provider