Which is better, Claude Opus 5.5 or GPT-6.1 Terra?

Claude Opus 5.5 scores higher on 2 of 6 shared quality measures, GPT-6.1 Terra on 1. 3 measures are too close to call. GPT-6.1 Terra costs about 75% less than Claude Opus 5.5 on a blended price of $2.00 against $8.00 per million tokens. Which one is better for you depends on your task and budget, so test both on your own work.

Which is cheaper, Claude Opus 5.5 or GPT-6.1 Terra?

GPT-6.1 Terra is cheaper on blended price: $8.00 per million tokens for Claude Opus 5.5 against $2.00 for GPT-6.1 Terra. For 100 chats of about 1,000 tokens in and 500 tokens back, that is about $1.40 for Claude Opus 5.5 and $0.35 for GPT-6.1 Terra.

Which can read longer documents, Claude Opus 5.5 or GPT-6.1 Terra?

Claude Opus 5.5 has a context window of 1M tokens and GPT-6.1 Terra has 922K tokens.

AI Rankings

Claude Opus 5.5 vs GPT-6.1 Terra: Scores, Price and Which to Choose

Side by side on every measure both models share: overall score, human votes, tests, price and context window. Close results are called too close to call.

Data updated 9 Nov 2026

Read the model pages for the full picture: Claude Opus 5.5 and GPT-6.1 Terra.

Side by side

A check mark shows the better side on each measure. Scores that are too close to call have no winner.

Claude Opus 5.5 compared with GPT-6.1 TerraClaude Opus 5.5 against GPT-6.1 Terra on 8 measures. Claude Opus 5.5 is better on 2, GPT-6.1 Terra on 2, 4 are too close to call, 0 have no data for one side.

Claude Opus 5.5
GPT-6.1 Terra

Epoch Capabilities IndexToo close to call
Combined score over many tests. Bar shows where it sits between the lowest and highest score we track.
Claude Opus 5.5:
168.4
GPT-6.1 Terra:
167.8
Arena web development ratingClaude Opus 5.5 leads
Rating from head-to-head votes by people. Bar shows where it sits between the lowest and highest score we track.
Claude Opus 5.5:
Better: 1818
GPT-6.1 Terra:
1678
FrontierMath (Tiers 1-3)Too close to call
Original, very hard maths problems written by mathematicians.
Claude Opus 5.5:
91.2%
GPT-6.1 Terra:
90.9%
GPQA DiamondGPT-6.1 Terra leads
Very hard multiple-choice science questions in biology, physics and chemistry, written by experts and designed so a quick web search does not give the answer.
Claude Opus 5.5:
90.6%
GPT-6.1 Terra:
Better: 94.3%
OTIS Mock AIMEToo close to call
Maths competition problems in the style of the US AIME exam, from the 2024 and 2025 sets.
Claude Opus 5.5:
100.0%
GPT-6.1 Terra:
100.0%
SimpleQA VerifiedClaude Opus 5.5 leads
Short factual questions that each have one correct answer.
Claude Opus 5.5:
Better: 72.2%
GPT-6.1 Terra:
57.3%
Blended price per million tokensGPT-6.1 Terra costs less
Blended price: lower is better.
Claude Opus 5.5:
$8.00
GPT-6.1 Terra:
Better: $2.00
Context windowToo close to call
How much text it can read at once.
Claude Opus 5.5:
1M tokens
GPT-6.1 Terra:
922K tokens

Data updated 9 Nov 2026. Only measures that both models have are shown.

The numbers

Claude Opus 5.5 against GPT-6.1 Terra, measure by measure. A check mark shows the better side.
Measure	Claude Opus 5.5	GPT-6.1 Terra
Epoch Capabilities IndexToo close to call	168.4	167.8
Arena web development rating	1818	1678
FrontierMath (Tiers 1-3)Too close to call	91.2%	90.9%
GPQA Diamond	90.6%	94.3%
OTIS Mock AIMEToo close to call	100.0%	100.0%
SimpleQA Verified	72.2%	57.3%
Blended price per million tokens	$8.00	$2.00
Context windowToo close to call	1M tokens	922K tokens

What it costs in everyday terms

Estimate for 100 chats of about 1,000 tokens in and 500 tokens back, from list prices. Your bill depends on how you use it.

100 chats with Claude Opus 5.5: $1.40; Blended price $8.00 per million tokens.
100 chats with GPT-6.1 Terra: $0.35; Blended price $2.00 per million tokens.

Who should pick which

Pick Claude Opus 5.5 if these matter most

Arena web development rating: 1818 against 1678
SimpleQA Verified: 72.2% against 57.3%

Pick GPT-6.1 Terra if these matter most

GPQA Diamond: 94.3% against 90.6%
Blended price per million tokens: $2.00 against $8.00

Too close to call: Epoch Capabilities Index, FrontierMath (Tiers 1-3), OTIS Mock AIME, Context window.

Scores come from tests and votes, not from your own work. Try both on a task you care about before you commit.

Go deeper

Claude Opus 5.5: full page

GPT-6.1 Terra: full page

Questions about this comparison

Which is better, Claude Opus 5.5 or GPT-6.1 Terra?: Claude Opus 5.5 scores higher on 2 of 6 shared quality measures, GPT-6.1 Terra on 1. 3 measures are too close to call. GPT-6.1 Terra costs about 75% less than Claude Opus 5.5 on a blended price of $2.00 against $8.00 per million tokens. Which one is better for you depends on your task and budget, so test both on your own work.
Which is cheaper, Claude Opus 5.5 or GPT-6.1 Terra?: GPT-6.1 Terra is cheaper on blended price: $8.00 per million tokens for Claude Opus 5.5 against $2.00 for GPT-6.1 Terra. For 100 chats of about 1,000 tokens in and 500 tokens back, that is about $1.40 for Claude Opus 5.5 and $0.35 for GPT-6.1 Terra.
Which can read longer documents, Claude Opus 5.5 or GPT-6.1 Terra?: Claude Opus 5.5 has a context window of 1M tokens and GPT-6.1 Terra has 922K tokens.

Where this data comes from

Epoch AI: Benchmark data: Epoch AI, 'Capabilities & benchmarking', epoch.ai/benchmarks (CC BY 4.0). We match models across sources, rank them and show them in charts. Scores are not changed. Epoch AI does not endorse this site.
Arena (formerly LMArena): Human-preference ratings: Arena (arena.ai) leaderboard dataset, CC BY 4.0. We keep the latest published ratings, match them to models from other sources and rank them. Ratings are not changed. Arena does not endorse this site.
LiteLLM model price list: Prices and context windows: LiteLLM model price list (github.com/BerriAI/litellm, MIT licence). We use the model maker's own price entry when there is one. Prices change often, so always confirm on the maker's site before you buy.

Newest data on this page: 9 Nov 2026. Prices are list prices and change often, so confirm on the maker's site before you buy. Sponsors never change a score or an order. How we calculate this · Report a mistake