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GPT-6 Luna vs GPT-6 Sol: pricing and benchmarks

GPT-6 Luna is 95% cheaper on input tokens ($0.10 vs $2.00 per 1M). GPT-6 Luna is 95% cheaper on output tokens ($0.50 vs $10.00 per 1M). On our document Q&A workload (50,000 questions a month), GPT-6 Luna costs $55.00 a month versus $1,100 for GPT-6 Sol, 95% less. Epoch AI has not published a capability index score for GPT-6 Luna and GPT-6 Sol yet.

Prices verified September 26, 2026.

Which should you choose?

Overall capability
Too close to call

Epoch AI has not published a capability index score for GPT-6 Luna and GPT-6 Sol yet.

Price
GPT-6 Luna

GPT-6 Luna costs $0.20 per 1M tokens (3:1 input-to-output mix) vs $4.00 for GPT-6 Sol, 95% less.

Pricing and specs

GPT-6 LunaGPT-6 Sol
ProviderOpenAIOpenAI
API model IDgpt-6-lunagpt-6-sol
Input / 1M tokens$0.10$2.00
Cached input / 1M tokens$0.01$0.20
Output / 1M tokens$0.50$10.00
Long-context rates$0.20 in / $0.75 out on long-context requests$4.00 in / $15.00 out on long-context requests
Context window1.05M tokens1.05M tokens
Max output128K tokens128K tokens
Batch discount50% off50% off

Monthly cost for real workloads

WorkloadGPT-6 LunaGPT-6 SolDifference
Support chatbot
100,000 replies a month, ~1,500 input tokens (system prompt + history) and ~400 output tokens each.
$35.00$700.00GPT-6 Luna 95% cheaper
Document Q&A (RAG)
50,000 questions a month with ~8,000 tokens of retrieved context and ~600 output tokens each.
$55.00$1,100GPT-6 Luna 95% cheaper
Coding agent
10,000 agent steps a month, ~40,000 input tokens each (70% read from the prompt cache) and ~2,000 output tokens.
$24.80$496.00GPT-6 Luna 95% cheaper

Estimates use standard list prices and ignore cache-write surcharges. Different tokenizers can count the same text differently, so test with your own prompts.

GPT-6 Luna vs GPT-6 Sol cost calculator

Standard-tier list prices. Long-context rates apply automatically where the provider publishes a threshold. Excludes cache-write surcharges, taxes, batch and volume discounts.

GPT-6 Luna pricing notes

OpenAI’s most efficient GPT-6 model, for focused, high-volume tasks.

  • Cache writes are billed at $0.125 per 1M tokens.
  • Fast mode costs 2x the standard rate; Flex costs half.
  • Regional (data residency) endpoints add a 10% uplift, and EU data residency is available only with standard processing.
OpenAI official pricing ↗

GPT-6 Sol pricing notes

OpenAI’s GPT-6 model built to power complex coding and agentic workflows.

  • Cache writes are billed at $2.50 per 1M tokens.
  • Fast mode costs 2x the standard rate; Flex costs half.
  • Regional (data residency) endpoints add a 10% uplift, and EU data residency is available only with standard processing.
OpenAI official pricing ↗

Frequently asked questions

Is GPT-6 Luna cheaper than GPT-6 Sol?
GPT-6 Luna is 95% cheaper on input tokens ($0.10 vs $2.00 per 1M). GPT-6 Luna is 95% cheaper on output tokens ($0.50 vs $10.00 per 1M). On our document Q&A workload (50,000 questions a month), GPT-6 Luna costs $55.00 a month versus $1,100 for GPT-6 Sol, 95% less.
Which is more capable, GPT-6 Luna or GPT-6 Sol?
Epoch AI has not published a capability index score for GPT-6 Luna and GPT-6 Sol yet.
How much does GPT-6 Luna cost per 1M tokens?
GPT-6 Luna costs $0.10 per 1M input tokens and $0.50 per 1M output tokens, and $0.01 per 1M cached input tokens on OpenAI’s standard tier.
How much does GPT-6 Sol cost per 1M tokens?
GPT-6 Sol costs $2.00 per 1M input tokens and $10.00 per 1M output tokens, and $0.20 per 1M cached input tokens on OpenAI’s standard tier.
Which has the larger context window, GPT-6 Luna or GPT-6 Sol?
Both offer a 1.05M-token context window.

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