Pairwise benchmark snapshot · Aug 16, 2026

Claude Opus 4.5 vs GPT-5.6 Terra benchmark

Name: Claude Opus 4.5 vs GPT-5.6 Terra AI benchmark comparison
Creator: CompareLLM
License: https://creativecommons.org/licenses/by/4.0/

This page compares Claude Opus 4.5 (Anthropic) and GPT-5.6 Terra (OpenAI) using the latest snapshots we have as of Aug 16, 2026. On preference Elo, Claude Opus 4.5 is ahead by 20 points (1,568 vs 1,548; seed-bootstrap (Aug 1, 2026)). On SWE-bench coding, Claude Opus 4.5 resolves 76.8% versus 70.4% (seed-bootstrap (Aug 1, 2026)). GPT-5.6 Terra streams faster (128 tok/s) while GPT-5.6 Terra is the cheaper output token ($6/1M). GPT-5.6 Terra has the larger context window (1.1M tokens). Every cell below is a dated snapshot from a named public source — we do not invent missing scores, and we do not run SWE-bench ourselves.

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Anthropic

Claude Opus 4.5

Anthropic frontier coding and computer-use model. SWE-bench leader on the official mini-SWE-agent harness in the Feb 2026 refresh.

Elo 1,568$25/1M out

OpenAI

GPT-5.6 Terra

OpenAI 5.6 mid tier. Official API $2/$12 per 1M after the Jul 30 2026 price cut.

Elo 1,548$6/1M out

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Quick vs:vs Claude Opus 4.6 vs Claude Sonnet 4.5 vs Claude 3.7 Sonnet vs GPT-5

Interactive Comparison Diagram

Matchup Breakdown

Tug-of-War Matchup Matrix

Category wins across intelligence, speed, and pricing efficiency.

Claude Opus 4.5 (5)vsGPT-5.6 Terra (5)

Claude Opus 4.5: 5W (50%)Overall: Even matchupGPT-5.6 Terra: 5W (50%)

← Claude Opus 4.5GPT-5.6 Terra →

Claude Opus 4.5 (5/5)

Intelligence & Reasoning

Preference Elo, Coding proficiency, SWE-bench & LiveBench accuracy

Preference Elo

1,568vs1,548

Coding Elo

1,574vs1,542

SWE-bench

76.8%vs70.4%

LiveBench

71.2%vs69.1%

GPQA Diamond

84.1%vs82%

Claude Opus 4.5: 5WGPT-5.6 Terra: 0W

GPT-5.6 Terra (2/2)

Speed & Latency

Generation throughput and time to first token responsiveness

Output speed

62 tok/svs128 tok/s

Time to first token

380 msvs160 ms

Claude Opus 4.5: 0WGPT-5.6 Terra: 2W

GPT-5.6 Terra (3/3)

Pricing & Capacity

Cost per million tokens and max context window length

Output price

$25/1Mvs$6/1M

Input price

$5/1Mvs$1/1M

Context window

200kvs1.1M

Claude Opus 4.5: 0WGPT-5.6 Terra: 3W

Capability Matchup Radar

Multi-Dimensional Capability Radar

Each spoke is a skill. Farther from the center is better (0–100th percentile). Tap any dot to inspect details.

Tap any node to inspect

Percentile 0–100

Dimensional AdvantageEven 3–3

Preference Elo

Claude Opus 4.5

20 pts advantage

Throughput Speed

GPT-5.6 Terra

66 tok/s faster

Price Efficiency

GPT-5.6 Terra

$19.00/1M cheaper

Full Benchmark Score Matrix

—

Elo

High is better

+1%1,568

EloHigh is better

1,548

Code Elo

High is better

+2%1,574

Code EloHigh is better

1,542

LiveBench

High is better

+3%71.2%

LiveBenchHigh is better

69.1%

SWE-bench

High is better

+9%76.8%

SWE-benchHigh is better

70.4%

GPQA

High is better

+3%84.1%

GPQAHigh is better

82%

TTFT

Low is better

380 ms

TTFTLow is better

160 ms+138%

Speed

High is better

62 tok/s

SpeedHigh is better

128 tok/s+106%

In $

Low is better

$5/1M

In $Low is better

$1/1M+400%

Out $

Low is better

$25/1M

Out $Low is better

$6/1M+317%

Context

High is better

200k

ContextHigh is better

1.1M+425%

Interactive Simulator

Workload Cost & Savings Calculator

Simulate monthly production API costs based on published $/1M tokens.

Save up to 77% with GPT-5.6 Terra

Monthly Volume50M tokens/mo

Quick Presets:

Token Ratio (In vs Out)70% In / 30% Out

RAG / Search (10% out)Coding / Chat (50% out)

Claude Opus 4.5$550.00 / mo

In: $175.00Out: $375.00

GPT-5.6 Terra$125.00 / mo

In: $35.00Out: $90.00

Estimated Cost Delta

GPT-5.6 Terra is estimated to save $425.00/month ($5,100/year).

Based on 50M tokens (30% gen)

Key Selection Recommendations

1
Claude Opus 4.5:Pick Claude Opus 4.5 when repo-level coding accuracy is the constraint.
2
GPT-5.6 Terra:Pick GPT-5.6 Terra when you are optimizing output cost.
3
GPT-5.6 Terra:Pick GPT-5.6 Terra when time-to-first-token matters more than peak Elo.

Recommended Workload Routing

Repo / coding agentsClaude Opus 4.5

Higher SWE-bench (76.8%).

High-volume chatGPT-5.6 Terra

Lower output list price ($6/1M).

Voice / low-latency UIGPT-5.6 Terra

Lower TTFT (160 ms).

Long-document RAGGPT-5.6 Terra

Larger window (1.1M).

Screenshots / visionClaude Opus 4.5

Both accept images. Defaulting to the higher-Elo side (Claude Opus 4.5).

Target Workload	Recommended Pick	Evaluation Rationale
Repo / coding agents	Claude Opus 4.5	Higher SWE-bench (76.8%).
High-volume chat	GPT-5.6 Terra	Lower output list price ($6/1M).
Voice / low-latency UI	GPT-5.6 Terra	Lower TTFT (160 ms).
Long-document RAG	GPT-5.6 Terra	Larger window (1.1M).
Screenshots / vision	Claude Opus 4.5	Both accept images. Defaulting to the higher-Elo side (Claude Opus 4.5).

Related Editorial Dispatches & Benchmark Notes

View all news

priceJul 30, 2026

GPT-5.6 Terra after the Jul 30 cut: $2/$12 mid-tier

Terra is OpenAI’s Sonnet-class invoice. Use it when Sol is too expensive and Luna is too small.

launchFeb 20, 2026

Claude Opus 4.5 and the Feb 2026 SWE-bench row we still cite

The Feb refresh made 4.5 a coding reference. Newer Opus SKUs exist; this row stays as the dated harness point.

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LIVE

Anthropic

Claude Opus 4.5

Elo 1,568

LiveBench71.2%

SWE-bench76.8%

Speed62 tok/s

Output cost$25/1M

OpenAI

GPT-5.6 Terra

Elo 1,548

LiveBench69.1%

SWE-bench70.4%

Speed128 tok/s

Output cost$6/1M

Frequently Asked Questions

Which is better overall, Claude Opus 4.5 or GPT-5.6 Terra?: Claude Opus 4.5 has the higher preference Elo in our latest snapshot (1,568). “Better” still depends on coding, price, and latency — see the table.
Which is better at coding, Claude Opus 4.5 or GPT-5.6 Terra?: Claude Opus 4.5 leads SWE-bench at 76.8% vs 70.4%. SWE-bench is one harness, not your repo.
Which is cheaper to run in production?: GPT-5.6 Terra output tokens are $6/1M versus $25/1M. Input prices and retry rates still move the real bill.
Which is faster, Claude Opus 4.5 or GPT-5.6 Terra?: GPT-5.6 Terra has the lower time-to-first-token (160 ms vs 380 ms). Tokens/sec is a separate column if you care about long completions.
Which has the larger context window?: GPT-5.6 Terra accepts 1.1M tokens versus 200k.
Can I self-host either model?: Neither model is marked open-weights here. You are comparing hosted APIs.
Are these scores from CompareLLM’s own evals?: No. V1 aggregates public leaderboards (and optional first-party latency pings). Each cell names its source and date. Read /methodology.
What does preference Elo mean on this page?: Preference Elo is a crowd vote from LMArena / Arena. People see two hidden answers and pick the one they like more. The model that wins more often gets a higher Elo. That means people preferred it — not that it passed a school test. It is not SWE-bench, not accuracy, and not a number we invent. Claude Opus 4.5 and GPT-5.6 Terra Elo cells are dated snapshots from the named source — we do not compute Arena ourselves.

Similar Head-to-Head Comparisons

All Claude Opus 4.5 matchups →|All GPT-5.6 Terra matchups →

Claude Opus 4.5 vs Claude Opus 4 (previous opus)Claude Opus 4.5 vs Claude Opus 4.6 (next opus)GPT-5 vs GPT-5.6 Terra Claude Sonnet 5 vs GPT-5.6 Terra GPT-4.5 Orion vs GPT-5.6 Terra Claude Opus 4.8 vs Claude Opus 4.5

Claude Opus 4.5 vs GPT-5.6 Terra benchmark

Interactive Comparison Diagram

Matchup Breakdown

Tug-of-War Matchup Matrix

Category wins across intelligence, speed, and pricing efficiency.

Claude Opus 4.5 (5)vsGPT-5.6 Terra (5)

Claude Opus 4.5: 5W (50%)Overall: Even matchupGPT-5.6 Terra: 5W (50%)

← Claude Opus 4.5GPT-5.6 Terra →

Claude Opus 4.5 (5/5)

Intelligence & Reasoning

Preference Elo, Coding proficiency, SWE-bench & LiveBench accuracy

Preference Elo

1,568vs1,548

Coding Elo

1,574vs1,542

SWE-bench

76.8%vs70.4%

LiveBench

71.2%vs69.1%

GPQA Diamond

84.1%vs82%

Claude Opus 4.5: 5WGPT-5.6 Terra: 0W

GPT-5.6 Terra (2/2)

Speed & Latency

Generation throughput and time to first token responsiveness

Output speed

62 tok/svs128 tok/s

Time to first token

380 msvs160 ms

Claude Opus 4.5: 0WGPT-5.6 Terra: 2W

GPT-5.6 Terra (3/3)

Pricing & Capacity

Cost per million tokens and max context window length

Output price

$25/1Mvs$6/1M

Input price

$5/1Mvs$1/1M

Context window

200kvs1.1M

Claude Opus 4.5: 0WGPT-5.6 Terra: 3W

Recommended Workload Routing

Repo / coding agentsClaude Opus 4.5

Higher SWE-bench (76.8%).

High-volume chatGPT-5.6 Terra

Lower output list price ($6/1M).

Voice / low-latency UIGPT-5.6 Terra

Lower TTFT (160 ms).

Long-document RAGGPT-5.6 Terra

Larger window (1.1M).

Screenshots / visionClaude Opus 4.5

Both accept images. Defaulting to the higher-Elo side (Claude Opus 4.5).

Target Workload	Recommended Pick	Evaluation Rationale
Repo / coding agents	Claude Opus 4.5	Higher SWE-bench (76.8%).
High-volume chat	GPT-5.6 Terra	Lower output list price ($6/1M).
Voice / low-latency UI	GPT-5.6 Terra	Lower TTFT (160 ms).
Long-document RAG	GPT-5.6 Terra	Larger window (1.1M).
Screenshots / vision	Claude Opus 4.5	Both accept images. Defaulting to the higher-Elo side (Claude Opus 4.5).

Frequently Asked Questions

Which is better overall, Claude Opus 4.5 or GPT-5.6 Terra?

Claude Opus 4.5 has the higher preference Elo in our latest snapshot (1,568). “Better” still depends on coding, price, and latency — see the table.

Which is better at coding, Claude Opus 4.5 or GPT-5.6 Terra?

Claude Opus 4.5 leads SWE-bench at 76.8% vs 70.4%. SWE-bench is one harness, not your repo.

Which is cheaper to run in production?

GPT-5.6 Terra output tokens are $6/1M versus $25/1M. Input prices and retry rates still move the real bill.

Which is faster, Claude Opus 4.5 or GPT-5.6 Terra?

GPT-5.6 Terra has the lower time-to-first-token (160 ms vs 380 ms). Tokens/sec is a separate column if you care about long completions.

Which has the larger context window?

GPT-5.6 Terra accepts 1.1M tokens versus 200k.

Can I self-host either model?

Neither model is marked open-weights here. You are comparing hosted APIs.

Are these scores from CompareLLM’s own evals?

No. V1 aggregates public leaderboards (and optional first-party latency pings). Each cell names its source and date. Read /methodology.

What does preference Elo mean on this page?

Preference Elo is a crowd vote from LMArena / Arena. People see two hidden answers and pick the one they like more. The model that wins more often gets a higher Elo. That means people preferred it — not that it passed a school test. It is not SWE-bench, not accuracy, and not a number we invent. Claude Opus 4.5 and GPT-5.6 Terra Elo cells are dated snapshots from the named source — we do not compute Arena ourselves.

Swap or Add Any Model to this Matchup

Interactive Comparison Diagram

Tug-of-War Matchup Matrix

Intelligence & Reasoning

Speed & Latency

Pricing & Capacity

Multi-Dimensional Capability Radar

Claude Opus 4.5

GPT-5.6 Terra

GPT-5.6 Terra

Full Benchmark Score Matrix

Workload Cost & Savings Calculator

Key Selection Recommendations

Recommended Workload Routing

Related Editorial Dispatches & Benchmark Notes

GPT-5.6 Terra after the Jul 30 cut: $2/$12 mid-tier

Claude Opus 4.5 and the Feb 2026 SWE-bench row we still cite

Cast Your Matchup Vote

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CompareLLM Matrix

Claude Opus 4.5

GPT-5.6 Terra

Frequently Asked Questions

Related news

Similar Head-to-Head Comparisons

Swap or Add Any Model to this Matchup

Interactive Comparison Diagram

Tug-of-War Matchup Matrix

Intelligence & Reasoning

Speed & Latency

Pricing & Capacity

Multi-Dimensional Capability Radar

Claude Opus 4.5

GPT-5.6 Terra

GPT-5.6 Terra

Full Benchmark Score Matrix

Workload Cost & Savings Calculator

Key Selection Recommendations

Recommended Workload Routing

Related Editorial Dispatches & Benchmark Notes

GPT-5.6 Terra after the Jul 30 cut: $2/$12 mid-tier

Claude Opus 4.5 and the Feb 2026 SWE-bench row we still cite

Cast Your Matchup Vote

Community Discussions (0)

Share card

CompareLLM Matrix

Claude Opus 4.5

GPT-5.6 Terra

Frequently Asked Questions

Related news

Similar Head-to-Head Comparisons