Claude Fable 5.1 Paid vs INMercury 3 Paid
Claude Fable 5.1 vs Mercury 3 compared — price per token, context window, multimodality, openness and which to choose. Full 2026 breakdown.
Claude Fable 5.1 — full profile › · Mercury 3 — full profile ›
Prices & specs refreshed from live data · olud.ai
Open-model prices = cheapest provider via OpenRouter; official maker rates may be higher.
$50 /M outputManaged API (no infra to run)
$0.35 /M outputManaged API (no infra to run)
Claude Fable 5.1 vs Mercury 3 specs
| Spec | Claude Fable 5.1 | Mercury 3 | Winner |
|---|---|---|---|
| Maker | Anthropic | Inception | – |
| Type | Proprietary | Proprietary | – |
| Context window | 1M tokens | 1M tokens | = Tie |
| Input price | $10/M | $0.1/M | INMercury 3 |
| Output price | $50/M | $0.35/M | INMercury 3 |
| Vision / multimodal | Yes | No | |
| Tool / function calling | Yes | Yes | = Tie |
| Self-hostable | No (API only) | No (API only) | – |
| License | Proprietary | Proprietary | – |
Price gap & when to choose each
Mercury 3 is ~143× cheaper than Claude Fable 5.1 on output tokens ($0.35 vs $50 per M tokens).
- You want frontier performance through a managed API
- You value reliability & ecosystem
- You don't want to manage infrastructure
- You want frontier performance through a managed API
- You want the lower output price
- You value reliability & ecosystem
- You don't want to manage infrastructure
Feature comparison
| Capability | Claude Fable 5.1 | Mercury 3 |
|---|---|---|
| Open weights (downloadable) | ✗ | ✗ |
| Self-hostable | ✗ | ✗ |
| Runs fully offline | ✗ | ✗ |
| Vision / multimodal | ✓ | ✗ |
| Tool / function calling | ✓ | ✓ |
| 1M+ context window | ✓ | ✓ |
Benchmarks: Claude Fable 5.1 vs Mercury 3
Independent benchmark scores measured by Artificial Analysis. Higher is better (except latency).
Benchmark data by Artificial Analysis.
How Claude Fable 5.1 and Mercury 3 score
| Criterion | Claude Fable 5.1 | Mercury 3 |
|---|---|---|
| Cost-efficiency | 2.0 | 5.0 |
| Context window | 5.0 | 5.0 |
| Openness | 1.5 | 1.5 |
| Self-hosting | 1.0 | 1.0 |
| Multimodality | 5.0 | 3.5 |
Scores come from live data — output price (cost), context length, open vs closed weights (openness & self-hosting) and vision/tool support (multimodality). Raw task quality isn't scored here; it depends on your benchmark — see the verdict.
What each model is
Claude Fable 5.1 Paid
Claude Fable 5.1 improves on Claude Fable 5 across the board, with the biggest gains in agentic coding, long-running agentic workflows, and knowledge work: long code refactors, front-end and visual...
Mercury 3 Paid
Mercury 3 is a diffusion-based language model from Inception, and the lab's most capable model to date. It is suited for agentic workflows and real-time applications where latency compounds, such...
Frequently asked questions
Claude Fable 5.1 vs Mercury 3 — which is cheaper?
Mercury 3 is cheaper on output ($0.35/M vs $50/M).
Which has the larger context window?
Claude Fable 5.1 offers the larger context window (1M tokens).
Claude Fable 5.1 vs Mercury 3 — which should I pick in 2026?
Choose Mercury 3 for the lower output price ($0.35/M vs $50/M). Choose Claude Fable 5.1 if you need the larger 1M context window.
People also compare
Explore more open-source AI
Browse the full open-source model leaderboard, thousands of tools and live benchmarks — all in one place.
Open the leaderboard →