Pick Claude Opus 5.5 for performs at roughly claude fable 5.1's level on most work, at 40% lower typical workload cost than opus 5 or anthropic reports it surpasses fable 5.1 on agentic coding, knowledge work, computer use, visual chart recognition, and multidisciplinary reasoning. Pick IBM Granite 4.1 for enterprise-grade open weights - apache 2.0, iso 42001-certified, cryptographically signed or efficient hybrid mamba-2/transformer design - much lower memory and faster inference. Choose IBM Granite 4.1 if you need self-hosting or data privacy; Claude Opus 5.5 if you want a managed API.
Claude Opus 5.5 (Anthropic) and IBM Granite 4.1 (IBM) are two of the models people most often weigh against each other in 2026. Claude Opus 5.5 is anthropic's September 22, 2026 update: Fable 5.1-level performance at 40% lower cost than Opus 5, with faster output and cheaper caching. IBM Granite 4.1 is iBM's most complete open-weight enterprise release - small, Apache-2.0, long-context and governance-friendly, built to deploy efficiently rather than top the leaderboard. They diverge most on price, context window and open vs. closed weights — each quantified below from the models' real specs.
Key differences
Cost model: IBM Granite 4.1 ships open weights you can self-host (hardware cost only, no per-token fee), while Claude Opus 5.5 is API-metered at $4/$20 per 1M tokens. Your choice depends on whether you want zero marginal cost at the price of running infrastructure.
Context window: Claude Opus 5.5 holds 2× more — 1M tokens (~1,500 pages) vs 512K (~768 pages). But effective recall usually fades long before the advertised ceiling, so the bigger number only helps if the model reasons over it.
Recency: Claude Opus 5.5 is the newer model by about 5 months (released September 22, 2026), usually meaning fresher training data and capabilities.
Specifications
Spec
Claude Opus 5.5
IBM Granite 4.1
Provider
Anthropic (US)
IBM (US)
Released
September 22, 2026
April 29, 2026
Context window
1M tokens (~1,500 pages)
512K (~768 pages)
Price (in/out)
$4/$20 per 1M tokens
Open weight (self-host / free)
Open weight?
No — API only
Yes — self-hostable
Modalities
text, image, code
text, code
SWE-Bench Verified
Not published
Not published
MRCR v2 @ 1M
Not published
Not published
Who wins what
Performs at roughly Claude Fable 5.1's level on most work, at 40% lower typical workload cost than Opus 5: Claude Opus 5.5 — Anthropic's September 22, 2026 update: Fable 5.1-level performance at 40% lower cost than Opus 5, with faster output and cheaper caching — and it carries the larger 1M tokens context.
Anthropic reports it surpasses Fable 5.1 on agentic coding, knowledge work, computer use, visual chart recognition, and multidisciplinary reasoning: Claude Opus 5.5 — IBM Granite 4.1 is comparatively weak here — best as a workhorse; reasoning-heavy tasks favor larger models
Pricing cut to $4/$20 per million tokens (20% below Opus 5's $5/$25), cache reads down 60% to $0.20/MTok: Claude Opus 5.5 — Its 1M tokens window holds about 2× more than IBM Granite 4.1's 512K in a single prompt.
Enterprise-grade open weights - Apache 2.0, ISO 42001-certified, cryptographically signed: IBM Granite 4.1 — Open weights make this possible at all — Claude Opus 5.5 is API-only, so it cannot leave the vendor's servers.
Efficient hybrid Mamba-2/transformer design - much lower memory and faster inference: IBM Granite 4.1 — Claude Opus 5.5 is comparatively weak here — not a reasoning-ceiling upgrade over Fable 5.1 — pitched as matching its performance at lower cost, not beating it outright
512K-token context on small, deployable dense models (3B/8B/30B): IBM Granite 4.1 — Claude Opus 5.5 is comparatively weak here — like Opus 5, the headline 1M-token context is not uniformly available across every platform and plan — some API paths default to a smaller window
Lowest cost at scale: IBM Granite 4.1 — Its weights are open, so at volume you pay for your own hardware instead of Claude Opus 5.5's $4/$20 per 1M tokens.
Largest single-prompt input: Claude Opus 5.5 — Its 1M tokens window is about 2× larger than IBM Granite 4.1's 512K, fitting roughly 1,500 pages in one prompt.
Which should you pick?
A cost-sensitive startup shipping high volume: IBM Granite 4.1 — At Open weight (self-host / free) it undercuts Claude Opus 5.5, and on millions of tokens that margin decides the monthly bill.
Someone analysing very long documents or codebases: Claude Opus 5.5 — Larger 1M tokens window fits more in one prompt.
A team with data-privacy or self-hosting needs: IBM Granite 4.1 — Open weights let you run it on your own hardware; Claude Opus 5.5 is API-only.
Anyone whose priority is performs at roughly claude fable 5.1's level on most work, at 40% lower typical workload cost than opus 5: Claude Opus 5.5 — It is specifically built for that.
Anyone whose priority is enterprise-grade open weights - apache 2.0, iso 42001-certified, cryptographically signed: IBM Granite 4.1 — That is its strongest area.
Claude Opus 5.5: where it fits
Anthropic's September 22, 2026 update: Fable 5.1-level performance at 40% lower cost than Opus 5, with faster output and cheaper caching. Released September 22, 2026 by Anthropic, it is built for performs at roughly Claude Fable 5.1's level on most work, at 40% lower typical workload cost than Opus 5, anthropic reports it surpasses Fable 5.1 on agentic coding, knowledge work, computer use, visual chart recognition, and multidisciplinary reasoning, pricing cut to $4/$20 per million tokens (20% below Opus 5's $5/$25), cache reads down 60% to $0.20/MTok, and output speed increased over 30% versus Opus 5.
Its trade-offs are real: not a reasoning-ceiling upgrade over Fable 5.1 — pitched as matching its performance at lower cost, not beating it outright, like Opus 5, the headline 1M-token context is not uniformly available across every platform and plan — some API paths default to a smaller window, and first model in the 5.5 line; Anthropic has signaled Sonnet 5.5 and Haiku 5.5 are still weeks away, so the lower tiers of the family aren't out yet. At $4 in / $20 out per million tokens, it sits in the mid price band.
IBM Granite 4.1: where it fits
IBM's most complete open-weight enterprise release - small, Apache-2.0, long-context and governance-friendly, built to deploy efficiently rather than top the leaderboard. Released April 29, 2026 by IBM, it is built for enterprise-grade open weights - Apache 2.0, ISO 42001-certified, cryptographically signed, efficient hybrid Mamba-2/transformer design - much lower memory and faster inference, 512K-token context on small, deployable dense models (3B/8B/30B), and free to self-host; governance-friendly for on-prem and regulated deployments.
Its trade-offs: not a frontier-intelligence competitor - built for efficient deployment, not top benchmark scores, best as a workhorse; reasoning-heavy tasks favor larger models, instruct models are text-focused (vision and speech are separate family members), and efficiency and performance claims are IBM's own. As an open-weight model, its running cost is your own hardware rather than a per-token fee.
The bottom line for this matchup
The defining split here is open vs. closed. IBM Granite 4.1 gives you weights you control — self-host it, fine-tune it, keep data in-house, pay only for hardware. Claude Opus 5.5 gives you a managed, always-updated API with no infrastructure to run. Teams with GPUs, privacy requirements, or huge volume often favour the open model; teams that want zero ops and the latest capabilities favour the closed one. Capability is close enough that this operational question, not the benchmark, usually decides it.
Frequently asked questions
Is Claude Opus 5.5 or IBM Granite 4.1 better for coding?
Public SWE-Bench figures are not available for either model, so the honest test is your own repository — run an identical real bug through both. By design, Claude Opus 5.5 leans toward performs at roughly claude fable 5.1's level on most work, at 40% lower typical workload cost than opus 5 while IBM Granite 4.1 leans toward enterprise-grade open weights - apache 2.0, iso 42001-certified, cryptographically signed, and that positioning usually predicts which feels better on your codebase.
Which is cheaper, Claude Opus 5.5 or IBM Granite 4.1?
IBM Granite 4.1 is open-weight, so self-hosting means no per-token fee (you pay for hardware instead), while Claude Opus 5.5 is API-metered at $4/$20 per 1M tokens. For most teams without GPUs, the API model is cheaper to start; at very high volume, self-hosting can win.
Which has the bigger context window?
Claude Opus 5.5 — 1M tokens vs 512K, about 2× larger. Useful only if the model actually reasons over the full window, which not all do.
Can I use both Claude Opus 5.5 and IBM Granite 4.1 together?
Yes — a multi-model platform like LumiChats gives you Claude Opus 5.5, IBM Granite 4.1 and 40+ others under one ₹69/day pass (about $1/day), so you can draft with one and cross-check with the other instead of buying two subscriptions.
Which is newer, Claude Opus 5.5 or IBM Granite 4.1?
Claude Opus 5.5 — released September 22, 2026, about 5 months after IBM Granite 4.1.
Claude Opus 5.5 vs IBM Granite 4.1
Anthropic · US | IBM · US · Updated June 2026
Quick verdict
Pick Claude Opus 5.5 for performs at roughly claude fable 5.1's level on most work, at 40% lower typical workload cost than opus 5 or anthropic reports it surpasses fable 5.1 on agentic coding, knowledge work, computer use, visual chart recognition, and multidisciplinary reasoning. Pick IBM Granite 4.1 for enterprise-grade open weights - apache 2.0, iso 42001-certified, cryptographically signed or efficient hybrid mamba-2/transformer design - much lower memory and faster inference. Choose IBM Granite 4.1 if you need self-hosting or data privacy; Claude Opus 5.5 if you want a managed API.
Claude Opus 5.5 (Anthropic) and IBM Granite 4.1 (IBM) are two of the models people most often weigh against each other in 2026. Claude Opus 5.5 is anthropic's September 22, 2026 update: Fable 5.1-level performance at 40% lower cost than Opus 5, with faster output and cheaper caching. IBM Granite 4.1 is iBM's most complete open-weight enterprise release - small, Apache-2.0, long-context and governance-friendly, built to deploy efficiently rather than top the leaderboard. They diverge most on price, context window and open vs. closed weights — each quantified below from the models' real specs.
Key differences at a glance
▸Cost model: IBM Granite 4.1 ships open weights you can self-host (hardware cost only, no per-token fee), while Claude Opus 5.5 is API-metered at $4/$20 per 1M tokens. Your choice depends on whether you want zero marginal cost at the price of running infrastructure.
▸Context window: Claude Opus 5.5 holds 2× more — 1M tokens (~1,500 pages) vs 512K (~768 pages). But effective recall usually fades long before the advertised ceiling, so the bigger number only helps if the model reasons over it.
▸Recency: Claude Opus 5.5 is the newer model by about 5 months (released September 22, 2026), usually meaning fresher training data and capabilities.
Side-by-side specs
Spec
Claude Opus 5.5
IBM Granite 4.1
Provider
Anthropic (US)
IBM (US)
Released
September 22, 2026
April 29, 2026
Context window
1M tokens (~1,500 pages)
512K (~768 pages)
Price (in/out)
$4/$20 per 1M tokens
Open weight (self-host / free)
Open weight?
No — API only
Yes — self-hostable
Modalities
text, image, code
text, code
SWE-Bench Verified
Not published
Not published
MRCR v2 @ 1M
Not published
Not published
Who wins what
Performs at roughly Claude Fable 5.1's level on most work, at 40% lower typical workload cost than Opus 5
Claude Opus 5.5
Anthropic's September 22, 2026 update: Fable 5.1-level performance at 40% lower cost than Opus 5, with faster output and cheaper caching — and it carries the larger 1M tokens context.
Anthropic reports it surpasses Fable 5.1 on agentic coding, knowledge work, computer use, visual chart recognition, and multidisciplinary reasoning
Claude Opus 5.5
IBM Granite 4.1 is comparatively weak here — best as a workhorse; reasoning-heavy tasks favor larger models
Pricing cut to $4/$20 per million tokens (20% below Opus 5's $5/$25), cache reads down 60% to $0.20/MTok
Claude Opus 5.5
Its 1M tokens window holds about 2× more than IBM Granite 4.1's 512K in a single prompt.
Enterprise-grade open weights - Apache 2.0, ISO 42001-certified, cryptographically signed
IBM Granite 4.1
Open weights make this possible at all — Claude Opus 5.5 is API-only, so it cannot leave the vendor's servers.
Efficient hybrid Mamba-2/transformer design - much lower memory and faster inference
IBM Granite 4.1
Claude Opus 5.5 is comparatively weak here — not a reasoning-ceiling upgrade over Fable 5.1 — pitched as matching its performance at lower cost, not beating it outright
512K-token context on small, deployable dense models (3B/8B/30B)
IBM Granite 4.1
Claude Opus 5.5 is comparatively weak here — like Opus 5, the headline 1M-token context is not uniformly available across every platform and plan — some API paths default to a smaller window
Lowest cost at scale
IBM Granite 4.1
Its weights are open, so at volume you pay for your own hardware instead of Claude Opus 5.5's $4/$20 per 1M tokens.
Largest single-prompt input
Claude Opus 5.5
Its 1M tokens window is about 2× larger than IBM Granite 4.1's 512K, fitting roughly 1,500 pages in one prompt.
Which should you pick?
A cost-sensitive startup shipping high volume
→ IBM Granite 4.1
At Open weight (self-host / free) it undercuts Claude Opus 5.5, and on millions of tokens that margin decides the monthly bill.
Someone analysing very long documents or codebases
→ Claude Opus 5.5
Larger 1M tokens window fits more in one prompt.
A team with data-privacy or self-hosting needs
→ IBM Granite 4.1
Open weights let you run it on your own hardware; Claude Opus 5.5 is API-only.
Anyone whose priority is performs at roughly claude fable 5.1's level on most work, at 40% lower typical workload cost than opus 5
→ Claude Opus 5.5
It is specifically built for that.
Anyone whose priority is enterprise-grade open weights - apache 2.0, iso 42001-certified, cryptographically signed
→ IBM Granite 4.1
That is its strongest area.
Claude Opus 5.5: where it fits
Anthropic's September 22, 2026 update: Fable 5.1-level performance at 40% lower cost than Opus 5, with faster output and cheaper caching. Released September 22, 2026 by Anthropic, it is built for performs at roughly Claude Fable 5.1's level on most work, at 40% lower typical workload cost than Opus 5, anthropic reports it surpasses Fable 5.1 on agentic coding, knowledge work, computer use, visual chart recognition, and multidisciplinary reasoning, pricing cut to $4/$20 per million tokens (20% below Opus 5's $5/$25), cache reads down 60% to $0.20/MTok, and output speed increased over 30% versus Opus 5.
Its trade-offs are real: not a reasoning-ceiling upgrade over Fable 5.1 — pitched as matching its performance at lower cost, not beating it outright, like Opus 5, the headline 1M-token context is not uniformly available across every platform and plan — some API paths default to a smaller window, and first model in the 5.5 line; Anthropic has signaled Sonnet 5.5 and Haiku 5.5 are still weeks away, so the lower tiers of the family aren't out yet. At $4 in / $20 out per million tokens, it sits in the mid price band.
IBM Granite 4.1: where it fits
IBM's most complete open-weight enterprise release - small, Apache-2.0, long-context and governance-friendly, built to deploy efficiently rather than top the leaderboard. Released April 29, 2026 by IBM, it is built for enterprise-grade open weights - Apache 2.0, ISO 42001-certified, cryptographically signed, efficient hybrid Mamba-2/transformer design - much lower memory and faster inference, 512K-token context on small, deployable dense models (3B/8B/30B), and free to self-host; governance-friendly for on-prem and regulated deployments.
Its trade-offs: not a frontier-intelligence competitor - built for efficient deployment, not top benchmark scores, best as a workhorse; reasoning-heavy tasks favor larger models, instruct models are text-focused (vision and speech are separate family members), and efficiency and performance claims are IBM's own. As an open-weight model, its running cost is your own hardware rather than a per-token fee.
The bottom line for this matchup
The defining split here is open vs. closed. IBM Granite 4.1 gives you weights you control — self-host it, fine-tune it, keep data in-house, pay only for hardware. Claude Opus 5.5 gives you a managed, always-updated API with no infrastructure to run. Teams with GPUs, privacy requirements, or huge volume often favour the open model; teams that want zero ops and the latest capabilities favour the closed one. Capability is close enough that this operational question, not the benchmark, usually decides it.
Want both Claude Opus 5.5 and IBM Granite 4.1 without two subscriptions? LumiChats gives you these plus 40+ models under one ₹69/day pass (about $1/day) — draft with one, cross-check with the other.
Is Claude Opus 5.5 or IBM Granite 4.1 better for coding?
Public SWE-Bench figures are not available for either model, so the honest test is your own repository — run an identical real bug through both. By design, Claude Opus 5.5 leans toward performs at roughly claude fable 5.1's level on most work, at 40% lower typical workload cost than opus 5 while IBM Granite 4.1 leans toward enterprise-grade open weights - apache 2.0, iso 42001-certified, cryptographically signed, and that positioning usually predicts which feels better on your codebase.
Which is cheaper, Claude Opus 5.5 or IBM Granite 4.1?
IBM Granite 4.1 is open-weight, so self-hosting means no per-token fee (you pay for hardware instead), while Claude Opus 5.5 is API-metered at $4/$20 per 1M tokens. For most teams without GPUs, the API model is cheaper to start; at very high volume, self-hosting can win.
Which has the bigger context window?
Claude Opus 5.5 — 1M tokens vs 512K, about 2× larger. Useful only if the model actually reasons over the full window, which not all do.
Can I use both Claude Opus 5.5 and IBM Granite 4.1 together?
Yes — a multi-model platform like LumiChats gives you Claude Opus 5.5, IBM Granite 4.1 and 40+ others under one ₹69/day pass (about $1/day), so you can draft with one and cross-check with the other instead of buying two subscriptions.
Which is newer, Claude Opus 5.5 or IBM Granite 4.1?
Claude Opus 5.5 — released September 22, 2026, about 5 months after IBM Granite 4.1.
Specifications and benchmarks reflect publicly reported figures as of June 2026 and may change as providers release updates. Always verify on your own workload.