API Pricing
Metered access to Calkulon's 4,600+ calculators. Start free, scale as you grow.
Hobby
100 calls/day
- 100 calls/day
- 1 API key
- Basic calculators
- Community support
Developer
10,000 calls/day
- 10,000 calls/day
- 3 API keys
- All calculators
- Webhook support
- Email support
Business
100,000 calls/day
- 100,000 calls/day
- 10 API keys
- All calculators
- Priority support
- SLA guarantee
Enterprise
Unlimited calls/day
- Unlimited calls
- 50 API keys
- Custom endpoints
- Dedicated support
- On-prem option
Frequently asked questions
How is API usage metered?
Each successful or failed request to /api/v1/calculate, /api/v1/calculators, or /api/v1/calculators/:slug counts against your plan's daily call limit. Limits reset every 24 hours from your last request.
What happens if I exceed my daily limit?
Requests beyond your daily limit return a 429 status with a Retry-After header. Upgrade your plan at any time to raise your limit immediately.
Can I use multiple API keys?
Yes. Each plan includes a maximum number of active API keys, useful for separating staging and production traffic. You can rename, rotate, or revoke keys from your API dashboard.
Do unused calls roll over?
No — daily call limits reset every 24 hours and do not accumulate or roll over.
How do I upgrade or downgrade?
Manage your subscription anytime from the API dashboard. Changes take effect immediately for upgrades; downgrades apply at the end of your current billing period.
Is there a free tier?
Yes — the Hobby plan is free forever and includes 100 calls/day and 1 API key, ideal for testing and small side projects.