Mercury 2.5 vs GPT-5.6 Luna
Side-by-side comparison of API pricing, specs, benchmarks, and capabilities
| Specification |
Mercury 2.5Intro price
by Inception
|
by OpenAI
|
|---|---|---|
| Overview | ||
| Status | Current budget | Current mid tier |
| Released | ||
| Pricing per million tokens | ||
| Input | $0.200/Mtok | $0.200/Mtok |
| Output | $0.750/Mtok | $1.20/Mtok |
| Blended avg | $0.338/Mtok | $0.450/Mtok |
| Cached input | $0.020/Mtok | $0.020/Mtok |
| Price basis | These are Inception's LIST prices, per 1M tokens. Mercury 2.5 is currently on an 80%-off promotion, so the rate you actually pay today is $0.04 input / $0.15 output / $0.004 cached input. Inception has not published an end date for the promotion, so we track the list price — the rate the model reverts to — rather than a discounted number that could expire without notice. Inception's own rate card shows both, listing Mercury 2.5 at $0.20 input / $0.02 cached / $0.75 output struck through, alongside the discounted prices. Inception's launch announcement states the same standard pricing of $0.20 / $0.75 per 1M tokens and describes $0.04 / $0.15 as a launch discount. Verified 2026-09-08. | — |
| Specifications | ||
| Context window | 260K tokens | 1M tokens |
| Parameters | Proprietary | Proprietary |
| Speed (TPS) | — | — |
| Modalities | ||
| Input |
text
|
textimage
|
| Benchmarks sources: public leaderboards / Vellum LLM Leaderboard | ||
| Avg benchmark score | — | 90.7 |
| Perf / dollar | — | 201.6 |
| GPQA Diamond | — | 92.3 |
| SWE-Bench Verified | — | 93 |
| Terminal-Bench 2.1 | — | 84.3 |
| HumanEval | — | 93 |
| Independent composite scores each on its own scale — not part of the average above | ||
| AA Intelligence Index | — | 37.5 |
| AA Agentic Index | — | 42.7 |
| AA-Omniscience Index (−100–100) | — | -10.3 |
| GDPval-AA v2 | — | 1489.3 ELO |
| Providers | ||
| Available from |
Inception — $0.200/$0.750/Mtok
|
OpenAI — $0.200/$1.20/Mtok
|
Cost at scale
1M tokens · 50/50 input/output| Volume | Mercury 2.5 | GPT-5.6 Luna | Savings |
|---|---|---|---|
| 1M tokens | $0.34 | $0.45 | $0.11 (24.4%) |
| 10M tokens | $3.38 | $4.5 | $1.13 (25.1%) |
| 100M tokens | $33.75 | $45 | $11.25 (25%) |
| 1000M tokens | $337.5 | $450 | $112.5 (25%) |
When to pick which
distilled from the pricing and spec data above- cost dominates: $0.338/Mtok blended vs $0.450 — 25% less on the same 50/50 token mix
- you need the longer context: 1M tokens vs 260K (4×)
Price movement
recorded changes since we began tracking each model · last checked| Model | Changes | Latest move | Old → new $/M |
|---|---|---|---|
| Mercury 2.5 | 0 | — no move | Stable since we began tracking — no change recorded |
| GPT-5.6 Luna | 1 | price cut on | $1/$6 → $0.2/$1.2/Mtok |
Summary
Mercury 2.5 by Inception costs $0.200/Mtok input and $0.750/Mtok output, with a 260K-token context window. It supports text input.
GPT-5.6 Luna by OpenAI costs $0.200/Mtok input and $1.20/Mtok output, with a 1M-token context window. It supports text, image input.
On a blended cost basis, Mercury 2.5 is 25% cheaper than GPT-5.6 Luna.
The two aren't directly comparable on average benchmark score: GPT-5.6 Luna has published per-benchmark results, while Mercury 2.5 does not yet.
Note: Pricing is per million tokens. Actual costs vary with usage patterns, prompt caching, and batch discounts. Always verify against official provider pricing pages.