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GPT-5.6 Luna Token Counter & Cost Calculator

Ultra-low-latency budget model engineered for high-frequency micro-tasks

Standard Input / 1M
$0.20
Prompt tokens
Cached Input / 1M
$0.10
Prompt caching rate
Output / 1M
$1.20
Generation completion
Context Window
128k
Max out: 16.4k

Interactive Cost & Token Simulator for GPT-5.6 Luna

Live Calculation
Input Tokens2,500
Output Tokens800
Requests / Day5,000
Prompt Caching Ratio (50%)$0.1/M cached rate
Cost / Request$0.00134
Daily Spend (5,000 reqs)$6.675
Monthly Run-Rate (30d)$200.25

Standard Workload Cost Scenarios

ScenarioInput TokensOutput TokensUncached CostWith Prompt Caching
Short Chat Query1,000500$0.00080$0.00070
Document Summarization10,0002,000$0.00440$0.00340
Codebase & Context Analysis100,00020,000$0.0440$0.0340
Batch Corpus Processing1,000,000100,000$0.3200$0.2200
Technical Architecture & Pricing VerificationVerified: September 8, 2026
Model ArchitectureGPT-5.6 Luna
Provider OrganizationOpenAI
Tokenizer EncodingOpenAI o200k_base (200k vocabulary)
API ConnectivityOpenAI Chat Completions API (/v1/chat/completions).
Batch API 50% DiscountSupported (50% off input & output)
Tier 1 Rate Quota5,000 RPM · 2M TPM
Blended 3:1 Cost / 1M Tokens$0.45
High-speed, low-cost model replacing GPT-4o-mini with enhanced multimodal reasoning.OpenAI Official Pricing

Verified Pricing History

August 2026: $0.15/M input · $0.6/M output ($0.075/M cached)
Replaces GPT-4o-mini at $0.15/1M input tokens.

When to Choose GPT-5.6 Luna

Ideal for production workloads demanding budget capabilities, deep context depth (128k tokens), and reliability from OpenAI. Excellent when predictable tokenomics and prompt caching support are paramount.

When Another Model May Be Better

If your use-case requires sub-second streaming latency or ultra-high frequency classification at micro-cent pricing, consider lighter budget options such as Gemini Flash-Lite or Claude Haiku. For deep formal logic, consider dedicated reasoning models like o3.

Frequently Asked Questions About GPT-5.6 Luna

How much does 1 million tokens cost with GPT-5.6 Luna?

For GPT-5.6 Luna, 1 million input tokens costs $0.20, while 1 million output tokens costs $1.20. If using prompt caching, repetitive input prefixes are discounted to $0.10 per million.

What is the context window for GPT-5.6 Luna?

GPT-5.6 Luna features a maximum context window of 128,000 tokens (~96,000 words), with a maximum output limit of 16,384 tokens per completion.

Which tokenizer does GPT-5.6 Luna use?

GPT-5.6 Luna utilizes the OpenAI o200k_base (200k vocabulary). Token counting on TokenMath runs client-side to ensure maximum privacy.

Does GPT-5.6 Luna support prompt caching discounts?

Yes. GPT-5.6 Luna supports prompt caching with a cached input rate of $0.10/1M (saving up to 50% on repeated input context).