If you're using Claude Sonnet 4 via Cursor AI, you're probably paying 20% more than you need to

How To
1

Just a heads-up for anyone using Claude Sonnet 4 inside Cursor AI without linking their own API key, you’re getting hit with a 20% markup on token usage.

Here’s the pricing breakdown:

Anthropic Direct API (base pricing):

  • $3 per 1M input tokens
  • $15 per 1M output tokens

Via Cursor AI (using their built-in key):

  • $3.60 per 1M input tokens
  • $18 per 1M output tokens

Yup, Cursor adds a 20% margin on top of Anthropic’s rates if you don’t bring your own key. Totally fair from a business perspective — they need to keep the lights on — but it does add up, especially if you’re doing large-scale dev or daily usage.

How to avoid the markup?

Just plug in your own Anthropic API key inside Cursor. Once that’s set, Cursor acts purely as a UI layer, and you’ll only be billed by Anthropic at their base rates. No extra fees. Same interface, cheaper backend.

TL;DR:

  • Using Cursor AI without your own key = 20% more expensive.
  • Add your own Anthropic key to Cursor = same tool, cheaper usage.
  • Cursor is great, just don’t overpay if you don’t need to.

Hope this saves someone a few bucks or a few hundred.

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3

Doesn’t this mean we’ll have to pay for “cursor subscription” + “Claude usage”? Currently, it’s “cursor subscription” only.

or it uses the key after the limit is reached ?

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4

Yes, if you link your own Claude API key, you’ll pay Claude usage separately on top of your Cursor subscription.

Cursor stops charging you for usage once your own key kicks in, but you start paying Anthropic directly.

So it’s either:

Cursor-only billing (with markup), or -

Cursor subscription + direct Claude API costs (no markup).

You choose what’s cheaper based on your usage.

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5

Many users have already used $150 of Sonnet for “free” with $20 Pro cursor sub, switching to your own key would be $125 of Claude usage + $20 Pro cursor.

When would it be worth it?

I’m guessing it’s when you’re always going over the limit and using the usage-based, but wouldn’t the “included in cursor sub” cover those markups

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6

If you stay within Pro limits, it’s cheaper to use Cursor’s included Claude.

But once you go over, Cursor charges a ~20% markup.

If you’re consistently going over, using your own Claude key is cheaper in the long run.

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8

So maybe use Pro up, then switch…monthly? as for me, i’m switching away from cursor entirely due to their surprise no-notification-at-all massive price increase. Found a “clarification” page on their site; I had suddenly noticed requests that used to be $.04 each were suddenly heading north of $.30. So ■■■■ 'em.

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9

oh, and they said they’d offer refunds to people who happened to notice prior to 7/4. too bad for those of us who thought they knew how it worked, i suppose.

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