LLM pricing · Compare

GPT-4.1 vs GPT-5.5 pricing (November 2026)

In short: GPT-4.1 is 3.1× cheaper than GPT-5.5 per chat message: $0.0062 vs $0.0195 for a typical chat turn (1,500 tokens in, 400 out). On a $9.99 plan, a user can send about 1,369 messages a month on GPT-4.1 before they cost more than they pay, versus 435 on GPT-5.5.

Price per million tokens

GPT-4.1GPT-5.5
ProviderOpenAIOpenAI
Input$2$5
Cached input$0.5$0.5
Output$8$30
Long promptssame rateover 272,000 tokens: $10 in, $45 out

Cost per message and per user

GPT-4.1GPT-5.5
Per message$0.0062$0.0195
Per message, prompt 2/3 cached$0.0047$0.0150
Light user (30 msgs/mo)$0.186$0.585
Typical user (300 msgs/mo)$1.86$5.85
Heavy user (3,000 msgs/mo)$18.60$58.50
Break-even on $9.991,369 msgs/mo435 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
$0.0062
AI cost per user / month
$1.86
Margin per user / month
$6.63
Break-even messages / month
1,369

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-4.1 or GPT-5.5 cheaper?

GPT-4.1 is 3.1× cheaper than GPT-5.5 per chat message: $0.0062 vs $0.0195 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 1,369 a month on GPT-4.1 and 435 on GPT-5.5, 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.