GPT-4o vs GPT-5.6 Luna — Side-by-side pricing
Side-by-side API pricing and tokenizer details for GPT-4o (OpenAI) and GPT-5.6 Luna (OpenAI).
Side-by-side pricing
| Feature | GPT-4o | GPT-5.6 Luna |
|---|---|---|
| Provider | OpenAI | OpenAI |
| Input (per 1M tokens) | $2.50 | $1.00 |
| Output (per 1M tokens) | $10.00 | $6.00 |
| Long-context pricing | Flat rate at any prompt size | Over 272K tokens: $2.00 in / $9.00 out |
| Context caching | No | Yes — 90% off cached tokens |
| Batch API discount | 50% off | 50% off |
| Context window | 128K tokens | 1.1M tokens |
| Tokenizer | o200k_base (tiktoken) | o200k_base (tiktoken) |
ⓘ GPT-4o: Deprecated by OpenAI. API access shuts down 2026-10-23; calls will error after that date. Prices are no longer listed on OpenAI's pricing page and could not be re-verified from a vendor source.
Real-world cost example
1,000 API requests per month, each with 500 input tokens and 200 output tokens (500K input + 200K output total).
GPT-4o
$3.2500
Input: $1.2500 +Output: $2.0000
GPT-5.6 Luna
$1.7000
Input: $0.5000 +Output: $1.2000
GPT-5.6 Luna is 48% cheaper for this workload — saving $1.5500 per month at this volume.
Frequently asked questions
No, GPT-5.6 Luna is cheaper for the typical workload above. At $1.00/1M input and $6.00/1M output tokens, it costs $1.7000 versus $3.2500 for GPT-4o — a 48% difference. Note that GPT-5.6 Luna switches to long-context pricing above 272K prompt tokens, so for very long prompts this gap does not scale linearly.
GPT-4o supports a 128K token context window. GPT-5.6 Luna supports a 1.1M token context window. A larger context window lets you include more text — documents, conversation history, or code — in a single API call.
GPT-4o does not support context caching. It offers a 50% Batch API discount. GPT-5.6 Luna supports context caching (90% off repeated tokens). It offers a 50% Batch API discount.
Yes, both GPT-4o and GPT-5.6 Luna use the o200k_base (tiktoken). The same text produces identical token counts on both models, so any cost difference is purely due to the rate each provider charges per token.
GPT-4o (OpenAI): $2.5 input / $10 output per 1M tokens. GPT-5.6 Luna (OpenAI): $1 input / $6 output per 1M tokens. Rates shown before caching or batch discounts.
For an 80% output / 20% input workload — typical for code generation or long-form writing — GPT-4o costs $8.5000 per 1M total tokens and GPT-5.6 Luna costs $5.0000. GPT-5.6 Luna is 41% cheaper for this pattern. For your exact ratio, paste a real prompt into the calculator above.
GPT-4o has a 128K-token context window — approximately 96K words or ~384 pages of standard text. GPT-5.6 Luna has a 1.1M-token context window — approximately 788K words or ~3K pages. (Estimates assume ~0.75 words per token.)
Calculate costs for your actual prompt
Paste your prompt into the calculator and get exact token counts using each model's real tokenizer — all in your browser.
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