GPT-5.5 API Pricing vs Claude Opus 4.8: The Real Cost Per Token in July 2026

Search interest in comparing GPT-5.5 and Claude Opus 4.8 pricing has climbed sharply in July 2026. With the keyword “gpt 5.5 api pricing” showing strong commercial intent at a CPC of $25.18, heavy AI users are clearly shopping for the best token value. This article breaks down the raw per-token costs, factors in prompt caching, and gives you a task-by-task comparison that subscription pages will never show you.

GPT-5.5 API Pricing: The Baseline

OpenAI’s GPT-5.5 is available through the standard API at $2.50 per million input tokens and $10 per million output tokens. These are flat rates with no tiered discounts unless you commit to a prepaid volume deal (starting at $5,000/month for bespoke pricing).

Key pricing details for GPT-5.5:

Input (standard): $2.50 / MTok
Output (standard): $10 / MTok
Batch API (50% discount): $1.25 / MTok input, $5 / MTok output (24h processing)
Prompt caching: Automatic, 50% discount on cached input tokens
Context window: 128K tokens

The batch API is significant for heavy users who can tolerate a 24-hour turnaround. A background analysis job that costs $50 at standard rates drops to $25 in batch mode. If your workload includes nightly report generation, batch data processing, or scheduled agent runs, the batch discount effectively halves your API bill.

Claude Opus 4.8 Pricing: The Premium Alternative

Anthropic prices Claude Opus 4.8 at $5 per million input tokens and $15 per million output tokens. That is 2x the input cost and 1.5x the output cost compared to GPT-5.5. But pricing alone does not tell the full story.

Claude Opus 4.8 pricing includes:

Input (standard): $5 / MTok
Output (standard): $15 / MTok
Prompt caching: 90% discount on cached input after first occurrence (Claude Code sessions can hit 85-95% cache hit rates)
Context window: 200K tokens
Fast mode: Available at $5 / MTok input, $25 / MTok output (lower latency, higher output cost)

The caching advantage is the headline. Where GPT-5.5 offers 50% on cached tokens, Claude Opus 4.8 gives 90%. In practice, this means a heavy user running 100 daily Claude Code sessions with a shared system prompt and file context will cache ~90% of input tokens after the first call.

Claude Sonnet 5: The Price-Performance Sweet Spot

Claude Sonnet 5, launched June 30, 2026 at intro pricing of $2 per million input tokens and $10 per million output tokens, directly matches GPT-5.5 on price while offering a different capability profile.

Model	Input/MTok	Output/MTok	Cache Discount	Context
GPT-5.5	$2.50	$10	50% cached	128K
Claude Opus 4.8	$5	$15	90% cached	200K
Claude Sonnet 5	$2	$10	90% cached	200K
Sonnet 4	$3	$15	90% cached	200K

Sonnet 5 intro pricing ends August 31, 2026. After that, pricing reverts to an announced but not yet published post-intro rate. Heavy users should lock in usage patterns now and calculate their post-August budget projection.

Real Cost Per Task: Three Scenarios

Pricing per token matters, but what matters to a heavy AI user is cost per task. Here are three common workloads.

Scenario 1: Single-shot code review (15K input, 2K output)

GPT-5.5: $0.0375 (input) + $0.02 (output) = $0.058
Claude Opus 4.8: $0.075 (input) + $0.03 (output) = $0.105
Claude Sonnet 5: $0.03 (input) + $0.02 (output) = $0.05

Winner: Sonnet 5 by a narrow margin. For single-shot tasks, there is no caching benefit. Sonnet 5 edges out GPT-5.5 by less than a cent.

Scenario 2: Multi-turn agent session (10 turns, 50K cached input + 5K new input + 3K output per turn)

GPT-5.5 with caching: First turn $0.125 + $0.03 = $0.155. Turns 2-10 at 50% cached: $0.0625 (cached) + $0.0125 (new) + $0.03 = $0.105/turn. Total: $1.10
Claude Opus 4.8 with caching: First turn $0.25 + $0.045 = $0.295. Turns 2-10 at 90% cached: $0.025 (cached) + $0.025 (new) + $0.045 = $0.095/turn. Total: $1.15
Claude Sonnet 5 with caching: First turn $0.10 + $0.03 = $0.13. Turns 2-10 at 90% cached: $0.01 (cached) + $0.01 (new) + $0.03 = $0.05/turn. Total: $0.58

Winner: Sonnet 5, dramatically. At 10 turns, Sonnet 5 costs half of GPT-5.5. The 90% cache rate on a long system prompt compounds rapidly.

Scenario 3: Bulk batch analysis (500 files, 2K input per file, 1K output, batch API)

GPT-5.5 batch: $1.25/MTok input, $5/MTok output. 1M input = $1.25, 500K output = $2.50. Total: $3.75
Claude Opus 4.8: Cached if same system prompt. First file $0.01 input, $0.015 output. Files 2-500 at 90% cached: $0.001 + $0.001 + $0.015 = $0.017/file. Total: ~$0.01 + 499 * $0.017 = $8.49
Claude Sonnet 5: First file $0.004 + $0.01 = $0.014. Subsequent at 90% cached: $0.0004 + $0.0004 + $0.01 = $0.0108/file. Total: ~$3.40

Winner: GPT-5.5 batch. But if you can batch with Sonnet 5 and achieve the same cache hit rate, Sonnet 5 edges ahead at $3.40 vs $3.75.

Prompt Caching: The Hidden Multiplier

The single most impactful variable in your API bill is the caching strategy. Here is why:

A typical Claude Code session sends ~33K tokens of scaffolding (system prompt, CLAUDE.md, tool definitions) before your first instruction. All of these are cacheable. With Claude’s 90% cache rate, only 3.3K of those tokens are charged fresh per turn. With GPT-5.5’s 50% cache rate, 16.5K of those same tokens are charged fresh.

Over a 50-turn daily session, that gap becomes significant:

Claude (90% cache): ~19K fresh input tokens per turn (3.3K scaffolding + 15K new context), charged at $5/MTok = ~$0.095 per turn. Daily: $4.75
GPT-5.5 (50% cache): ~32K fresh input tokens per turn (16.5K scaffolding + 15K new context), charged at $2.50/MTok = ~$0.08 per turn. Daily: $4.00
Sonnet 5 (90% cache): Same as Claude above, charged at $2/MTok = ~$0.038 per turn. Daily: $1.90

Sonnet 5 wins again. The combination of low base pricing with deep cache discounts creates a compounding effect that widens with session length.

Cross-Provider Comparison

Metric	GPT-5.5	Claude Opus 4.8	Claude Sonnet 5
Per MTok input	$2.50	$5	$2
Per MTok output	$10	$15	$10
Cache discount	50%	90%	90%
Batch discount	50%	No	No
Context window	128K	200K	200K
Best for	Batch jobs, one-shot completions	Complex reasoning, deep context	Cost-sensitive agent loops

If your workload is heavy on single-shot, batchable API calls (like data extraction or classification), GPT-5.5 with batch pricing is the cheapest option per task. If you run long multi-turn agent sessions with shared context (Claude Code, Cursor, custom agents), Claude Sonnet 5 edges ahead due to the 90% cache rate on large scaffolding.

What Heavy Users Can Do Now

Audit your current usage profile. Run a week-long token trace on your actual workload and categorize tasks by turn depth and cacheability. The tool that looks cheap on the pricing page (lower per-MTok rate) may be more expensive in practice if its cache hit rate is lower and your workload is multi-turn.

Set up a routing strategy. Use Claude Sonnet 5 for standard agent sessions, GPT-5.5 batch for bulk processing, and reserve Claude Opus 4.8 for tasks where depth and context size genuinely matter (complex refactors, legal analysis, long-document reasoning).

Lock in Sonnet 5 intro pricing before August 31. If you are a volume user, compute your projected monthly consumption and assess whether a prepaid commitment with OpenAI or Anthropic changes the math.

Conclusion

The cheapest model on paper is GPT-5.5 at $2.50/$10 per MTok. In practice, Claude Sonnet 5 at the same price with 90% cache rates can be meaningfully cheaper for the majority of agent-based workloads. Claude Opus 4.8 is 2x the input cost of GPT-5.5 and only justifies that premium on tasks that genuinely need the additional reasoning depth. Heavy users spending $500+/month should model their actual turn patterns before choosing a primary provider, because the difference between 50% and 90% cache rates compounds to hundreds of dollars per month.