ChatGPT Plus vs API: Cost Comparison

Posted on May 19, 2024, by Zhu Liang

For people leveraging AI to aid in coding, understanding the cost implications of ChatGPT Plus subscription versus the GPT-4o API is crucial. Both options offer access to powerful AI models, but their cost structures differ significantly.

The recent price drop from GPT-4 Turbo to GPT-4o makes the API a more attractive option. Here are the current rates:

GPT-4o:

  • Input: $5.00 per million tokens
  • Output: $15.00 per million tokens

GPT-4 Turbo:

  • Input: $10.00 per million tokens
  • Output: $30.00 per million tokens

The ChatGPT Plus subscription costs $20 per month, providing unlimited access to the web-based ChatGPT service. On the other hand, the GPT-4o API charges $5.00 per million input tokens and $15.00 per million output tokens (source). This post will compare these costs based on token usage for daily and occasional coding tasks.

Daily Coding Tasks

Developers who write code daily can easily generate a high token count. Let's assume an average developer writes 200 lines of Python code per task, which translates to about 1,700 tokens.

We assume each task involves three iterations with ChatGPT, and we work on five tasks per day. Each iteration involves both input and output tokens, assuming the number of output tokens is the same as input tokens.

  1. Per Task:

    • Input tokens: 1,700 tokens
    • Output tokens: 1,700 tokens
  2. Per Day:

    • Input tokens: 25,500 tokens (1,700 tokens/task × 3 iterations × 5 tasks)
    • Output tokens: 25,500 tokens (1,700 tokens/task × 3 iterations × 5 tasks)
  3. Per Month (assuming 5 days a week, 4 weeks a month):

    • Input tokens: 510,000 tokens (25,500 tokens/day × 20 days)
    • Output tokens: 510,000 tokens (25,500 tokens/day × 20 days)
  4. Total Monthly API Cost:

    • Input tokens cost: 510,000 tokens × $5.00 / 1,000,000 tokens = $2.55
    • Output tokens cost: 510,000 tokens × $15.00 / 1,000,000 tokens = $7.65
    • Total monthly API cost: $2.55 + $7.65 = $10.20

Occasional Coding Tasks

For non-tech users or developers who code occasionally, the token count is significantly lower.

Assuming they write 200 lines of React code (about 1,500 tokens) per task, with one task per week:

  1. Per Task:

    • Input tokens: 1,500 tokens
    • Output tokens: 1,500 tokens
  2. Per Week:

    • Input tokens: 4,500 tokens (1,500 tokens/task × 3 iterations)
    • Output tokens: 4,500 tokens (1,500 tokens/task × 3 iterations)
  3. Per Month (assuming 4 tasks a month):

    • Input tokens: 18,000 tokens (4,500 tokens/day × 4 days)
    • Output tokens: 18,000 tokens (4,500 tokens/day × 4 days)
  4. Total Monthly API Cost:

    • Input tokens cost: 18,000 tokens × $5.00 / 1,000,000 tokens = $0.09
    • Output tokens cost: 18,000 tokens × $15.00 / 1,000,000 tokens = $0.27
    • Total monthly API cost: $0.09 + $0.27 = $0.36

Cost Effectiveness Analysis

Based on the calculations, the GPT-4o API is more cost-effective for both daily and occasional coding tasks compared to the ChatGPT Plus subscription.

For daily coders, the total monthly cost of using the GPT-4o API is around $10.20, significantly lower than the $20 per month subscription fee. Occasional coders also benefit from the lower API costs, spending only about $0.36 per month.

However, the ChatGPT Plus subscription offers additional benefits that may justify the higher cost for some users. With ChatGPT Plus, you get unlimited access to the ChatGPT web and mobile apps, allowing you to ask non-coding general questions on the go. This can be particularly useful for quick queries, brainstorming, or getting assistance outside of coding tasks.

16x Prompt: Enhancing Efficiency

Whether using ChatGPT Plus or the GPT-4o API, integrating tools like 16x Prompt can optimize your experience. This tool streamlines coding by enhancing prompt quality and managing context effectively, ensuring better results.

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