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models on vapi have a base price + a price per tok...
# support
s
hey.. as stated how do I know? with such system prompt : Tokens: 3798 Characters: 16235 with claude sonnet 4.5 I see price : 0.14761 $ /min (only for model) with NO system prompt, Sonnet 4.5 too I see Cost (USD) 0.0015 $ /min So, I assume there is a base price, in 4.5 sonnet case : 0.0015, to which we add an estimation per minute of tokens used? I guess? using price per 1M / token displayed here : https://vapi.ai/pricing am I correct? can we know more about the estimation? would it be possible to have the formula instead of reverse eengineering them all? would help a lot, as I'm building my pricing on top of vapi's thanks! here is what claude told me is it right?
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md
Token cost calculation:
Base cost (no system prompt):

0.0015 USD/min

With your system prompt:

0.14761 USD/min

Difference:

0.14761 - 0.0015 = 0.14611 USD/min from system prompt

Your system prompt tokens:

3798 tokens

Price per 1M input tokens (Sonnet 4.5):

$3/1M input = $0.000003 per token

Formula they're using:
cost_per_min = (tokens × price_per_token × messages_per_min)
Checking math:
0.14611 / 60 seconds = 0.002435 per second
0.002435 / 0.000003 = 811.67 tokens per second
811.67 / 3798 = 0.214 messages per second
= 12.8 messages per minute
Their estimation formula:
system_prompt_tokens × $0.000003 × ~13 messages/min ≈ cost/min
3798 × 0.000003 × 13 = 0.148 USD/min ✓
They assume ~13 message exchanges per minute to calculate the per-minute cost impact of system prompts.
https://cdn.discordapp.com/attachments/1426982494774890547/1426982495085400174/CleanShot_2025-10-12_at_19.15.402x.png?ex=68ed3482&is=68ebe302&hm=b521bd2e5a6d983c6a4dfd4313ab764f1642f13b09f6107575d7702d8423675a&
c
Hi there, Thank you for your message. Our team is currently out of the office. We operate Monday through Friday, from 9:00 AM to 8:00 PM Pacific Standard Time (PST). We’ll get back to you as soon as possible during our normal business hours. If your message is urgent, please mark it accordingly or include “URGENT” in the subject line, and we’ll do our best to respond promptly. Warm regards, Vapi Customer Support Team
Hi Sparkls, For estimating the costs incurred using Vapi, you can refer to the tokens used by the models in your calls. The cost field in the API response reflects different components like LLM usage and external providers such as Deepgram and Eleven Labs. You can use the token usage provided by the API and multiply it by the per-token price of the models you are utilizing to get an estimated cost for a call. Vapi charges a small fee on top of the direct vendor costs for maintaining and improving the platform. For detailed pricing information, you may want to consult the [Vapi pricing page](https://docs.vapi.ai/faq).
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