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In this guide
What does the error mean?
The full message reads:
Your credit balance is too low to access the Anthropic API. Please go to Plans & Billing to upgrade or purchase credits.
Anthropic’s help center puts it plainly. If you run out of credits, you can’t call the API or use the playground until you add more. In Claude Code the same problem appears as Credit balance too low · Add funds: https://platform.claude.com/settings/billing.
Anthropic’s docs show the message without a status code. Reports in Anthropic’s own GitHub repo show it coming back as a 400 with type invalid_request_error, so code that only watches for 429s will miss it.
Your AI bill, with ernd
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Enter an amount from $0 to $100,000,000.
back a year at 4%
For US companies. No annual fee. Illustration based on AI vendor spend only. Rewards are points redeemable as cash back.
How do you fix it?
- Sign in to the Claude Console with an Admin or Billing role. Buying credits needs one of those.
- Open the Billing page and click Buy credits.
- Enter an amount and confirm. The credits are available straight away.
- If the error continues, check which organization the API key belongs to. A key from a different organization keeps failing however much you add to this one.
Claude Max, Ultra and Team plans come with monthly API credits for a linked Console organization. If that’s all the organization has, requests stop until next month’s credits arrive, unless you buy credits or turn on auto-reload.
How do you keep it from coming back?
Turn on auto-reload. In the Credit balance section of the Billing page, click Set up auto-reload. Fill in When credit balance reaches with your threshold and Bring credit balance back up to with the target, then turn it on. If your balance is already at or below the threshold, you’re charged right away.
Auto-reload is only as reliable as the card it charges. If that card declines, the balance keeps falling until calls stop. ernd is a credit card for AI spend that earns 4% back on bills like this one.
A monthly spend cap applies on top of your balance. When you hit it, you get a different error, covered on our usage limits page.
The ernd card
Once your billing is back on track.
The card earns rewards on AI spend. It does not bypass provider quotas, fix account restrictions or change provider prices.
Request your cardThe ernd card is a credit card for US companies, with partners across the AI stack built in.
Common questions.
How fast do Anthropic credits show up?
Right away. Anthropic's help center says purchased credits are available immediately.
Do Anthropic API credits expire?
Yes, one year from the purchase date, and the date can't be extended. Credit purchases are non-refundable.
Does a Claude Pro or Max subscription pay for API calls?
Not directly. Claude Max, Ultra and Team plans include monthly API credits once you link a Console organization to the plan. Unused ones expire at the end of each billing cycle, and past them API usage needs purchased credits.
Sources & methodology
Checked . Providers change prices and terms; the linked official page is the final word. This guide is published by ernd.
ernd is run by Provenance Research Inc.