Claude Fast Mode

 

What if you want Claude to speed things up and get you an answer back faster?  Well Claude has a mode for that, Fast mode!  But there is going to be a costs!

 

 

What is fast mode?

The fast mode delivers up to 2.5 faster output token generation while using the exact same model, weights, intelligence and capabilities as the standard version.  Long story short its just faster, simple as that.

It is only available in Opus

If we are looking at token cost via the API https://claude.com/pricing#api [1]

If we look at Opus we can see that input is $5/MTok and output is $25/MTok

If we look at fast pricing https://platform.claude.com/docs/en/about-claude/pricing#fast-mode-pricing

We can see that Opus 4.6/4.7 costs $30/Mtok for input and $150/MTok for output.  But for Opus 4.8 its 3x cheaper $10/MTok for  input and $50/MTok for output.

So…. If you are using Opus 4.6/4.7 you are going to spend 6X for fast and for Opus 4.8 you will spend 2x for fast

 

Let’s test this

 

Let me see if Claude will track time of a prompt

Run this prompt

> While I am in this session when you complete a task after a prompt post how long it took to complete in seconds

>  I am going to be running some speed test.  If I ask you to do the same thing over and over again do not use any previous learned information just start fresh. Do not read any previously created files just replace them

 

Let’s give it something to do

> Create a complete Python class called `TaskManager` with the following features: - Add a task (with title, description, due date) - Mark a task as complete - List all pending tasks - List all completed tasks - Delete a task - Save tasks to a JSON file - Load tasks from a JSON file  Use proper type hints, docstrings, and include example usage at the bottom. Make it production-quality code.

 

OK … it asked for some permissions but it took 62 seconds.

Let me rerun it

Run 1 :  26 seconds
Run 2:   26 seconds
Run 3:   25 seconds
Run 4:   31 seconds

Now lets switch to fast mode

>  /fast on

It gives you a price warning

OK let’s try it

> Create a complete Python class called `TaskManager` with the following features: - Add a task (with title, description, due date) - Mark a task as complete - List all pending tasks - List all completed tasks - Delete a task - Save tasks to a JSON file - Load tasks from a JSON file  Use proper type hints, docstrings, and include example usage at the bottom. Make it production-quality code.

 

Run 1:  26 seconds
Run 2:  26 seconds
Run 3:  26 seconds
Run 4:  25 seconds

OK…

No real difference in this example.

Asking AI why?  It came back with this.

Fast Mode primarily speeds up output token generation rate (how fast tokens stream out once Claude starts writing). It does not significantly speed up: Thinking / reasoning time before output starts Time to first token Tool calls or permission checks (if any) Your test prompt (TaskManager class) is medium-length output. For prompts like this, a lot of the total time is spent in reasoning rather than pure token generation. That's why normal and fast mode ended up very close (mostly in the 25–26 second range). This is a common observation from people who have tested it.

 

Second example

Let’s try a second example

Turn fast off

>  /fast off

>  Build a full React + TypeScript dashboard for a project management tool. Include: - Sidebar navigation - Task board with drag and drop (using a library) - Modal for creating/editing tasks - API service layer - State management (Zustand or Redux) - Responsive design - Dark mode support  Generate all the main components and files.

 

First run: 210 seconds
Second run : 171 seconds 

Now turn fast mode on and retry

Oh! It got turned off on me.
How odd since I am paying per token and not on a monthly plan

OK waiting 30 min then trying this again.

Looking at Handle rate limits https://code.claude.com/docs/en/fast-mode#handle-rate-limits [2]

Looks like if you are on a sub plan, you have to pay extra, and if you run out of credits it will fall back to normal speed (not my case).

But for everyone there is a rate limit pool, which I can’t seem to find… So I guess I just wait 30 min.

 

First run: 180 seconds
Second run: 316 seconds

OK so… no real improvements maybe even it was worse.

 

 

Subscription plans

OK what about subscription plans?  Looking at their web site https://code.claude.com/docs/en/fast-mode  [3]

It looks like you can use /fast mode but you will pay extra for it.

For Claude Code users on subscription plans (Pro/Max/Team/Enterprise), fast mode is available via usage credits only and not included in the subscription rate limits.

So you can use it but you are gonna pay extra.

 

 

Final Thoughts

 

I do not see any real reason to use this at this time, maybe that will change in the future.  I could see a value in paying 2-3x more for getting 2-3x overall speed up but its just not there yet.  Also with limits on when and how I can use it now… When I need it would it even be available.

Give it a year or two and we will see how this turns out.

 

References

 

[1]      Claude Pricing
            https://claude.com/pricing#api
           Accessed 05/2026
[2]       Handle rate limits
             https://code.claude.com/docs/en/fast-mode#handle-rate-limits
            Accessed 05/2026
[3]       Speed up responses with fast mode
             https://code.claude.com/docs/en/fast-mode
            Accessed 05/2026