LLM pricing · Compare

GPT-5 nano vs GPT-6 luna pricing (November 2026)

In short: GPT-5 nano is 1.5× cheaper than GPT-6 luna per chat message: $0.00023 vs $0.00035 for a typical chat turn (1,500 tokens in, 400 out). On a $9.99 plan, a user can send about 36,134 messages a month on GPT-5 nano before they cost more than they pay, versus 24,261 on GPT-6 luna.

Price per million tokens

GPT-5 nanoGPT-6 luna
ProviderOpenAIOpenAI
Input$0.05$0.1
Cached input$0.005$0.01
Output$0.4$0.5
Long promptssame rateover 272,000 tokens: $0.2 in, $0.75 out

Cost per message and per user

GPT-5 nanoGPT-6 luna
Per message$0.00023$0.00035
Per message, prompt 2/3 cached$0.00019$0.00026
Light user (30 msgs/mo)$0.0070$0.0105
Typical user (300 msgs/mo)$0.0705$0.105
Heavy user (3,000 msgs/mo)$0.705$1.05
Break-even on $9.9936,134 msgs/mo24,261 msgs/mo

Red: the user costs more in AI than the $8.49 you keep from a $9.99 plan after a 15% store fee.

Which to use

Price is only half of it: pick the cheapest model that gives answers your users accept. Many apps route most traffic to the cheaper model and send only hard requests, or only paying users, to the stronger one. Whatever the mix, the number that decides your margin is cost per user, because a few heavy users usually drive most of the bill.

Try your own numbers

Cost per message
$0.00023
AI cost per user / month
$0.07
Margin per user / month
$8.42
Break-even messages / month
36,134

List prices, standard tier, prompts under the long-context threshold. Averages hide your heaviest users: FiscaLLM shows this per real user.

Track the real cost of each user

FiscaLLM prices every OpenAI call with these rates, per user, and sets it next to what that user paid through RevenueCat, Stripe or a CSV. You see which users and which model lose you money. Free and open source. See the demo.

Questions

Is GPT-5 nano or GPT-6 luna cheaper?

GPT-5 nano is 1.5× cheaper than GPT-6 luna per chat message: $0.00023 vs $0.00035 for a 1,500-token prompt and a 400-token reply, at list prices.

How many messages can a $9.99 subscriber send on each?

About 36,134 a month on GPT-5 nano and 24,261 on GPT-6 luna, before AI cost uses up what you keep after a 15% store fee.

Can I use both?

Yes. A common pattern is the cheaper model for most traffic and the stronger one for hard requests or paying users. Track cost per user to see whether the mix pays off.

List prices, standard tier. Batch, priority and regional pricing differ; check each provider for the latest.