Pricing
Free calculators.
Infrastructure for every scale.
Every calculator on this site is free and stays free. The API covers one thing: programmatic access — the REST API, the data feeds, receipt issuance. It is free during launch with documented rate limits; this page never invents a number.
Free
Free forever
Everything a person needs. The math is never paywalled.
- All 122 web calculators
- Embeddable widget, with attribution
- Public MCP server for AI agents
- VCC receipt verification
- No account, no trial clock
Developer
Free during launch
The same deterministic math, as a service for your software.
- REST endpoints for all 122 calculators
- Zod-validated inputs, JSON in / JSON out
- OpenAPI spec and documentation
- Anonymous trial — no key required to start
- Documented platform rate limits
Pro
Free during launch
Everything in Developer, plus the data and proof layers.
- Everything in Developer
- Graph API
- AI pricing feed
- VCC issuance on the pilot formulas
- Email support
Business
Contact sales
Between Pro and a full enterprise deal. Not self-serve yet — every line below is scoped with you.
- Higher API volumes — contact sales
- Team access — contact sales
- Extended data retention — contact sales
- Priority support — contact sales
Enterprise
Custom agreement
Not a checkbox tier — an offer we scope together with you.
- Private formulas on the same engine
- Managed VCC: keys, retention, custom issuer
- BYOK / KMS key management
- Custom volumes and terms
Compare plans
Only facts that are true today. Where a capability is an offer rather than a shipped feature, the cell says contact sales.
| Feature | Free | Developer | Pro | Business | Enterprise |
|---|---|---|---|---|---|
| API requests | Not included | Tools API · up to 120 req/min* | + Graph & AI pricing feed* | Contact sales | Contact sales |
| API key | Not included | Free cf_ key (optional) | Free cf_ key (optional) | Contact sales | Contact sales |
| MCP server (public) | Included | Included | Included | Included | Included |
| Copilot (web) | 15/day · access pass available | 15/day · access pass available | 15/day · access pass available | Contact sales | Contact sales |
| Graph API | Not included | Not included | Included | Contact sales | Included |
| AI pricing feed | Not included | Not included | Included | Contact sales | Included |
| VCC verification | Included | Included | Included | Included | Included |
| VCC issuance | Not included | Not included | Pilot formulas | Contact sales | Managed — contact sales |
| Widget embed | Included | Included | Included | Included | ✓ · white-label: contact sales |
| Saved history | Not included | Not included | Not included | Contact sales | Contact sales |
| Exports | Not included | Not included | Not included | Contact sales | Contact sales |
| Webhooks | Not included | Not included | Not included | Contact sales | Contact sales |
| Team access | Not included | Not included | Not included | Contact sales | Contact sales |
| SSO | Not included | Not included | Not included | Not included | Contact sales |
| Support | Self-serve docs | Self-serve docs | Priority — contact sales | Contact sales | |
| Private formulas | Not included | Not included | Not included | Not included | Contact sales |
| Custom issuer identity | Not included | Not included | Not included | Not included | Contact sales |
* Platform-wide protective per-IP rate ceilings, from the published configuration: tools API 120 requests/min, Graph API 30/min, AI pricing feed 30/min, MCP 60/min, VCC verification 30/min. A free cf_ key raises them. Exceeding a ceiling returns 429 with a Retry-After header and a documentationUrl.
The web Copilot is free for everyone with a daily limit of 15 prompts; an access pass removes the limit.
Free during launch
The API is free while we launch: an anonymous trial plus free cf_ keys for higher rate limits, all documented above. Priced tiers will be published before they ever apply — until a number is real and public, this page says “Contact sales” instead of guessing. No trials that silently convert, no hidden fees, no fake urgency.
Honest questions
Is the free tier really free?
Yes. All 122 web calculators, the embeddable widget, the public MCP server and VCC receipt verification are free, with no account required. The site is supported by clearly marked ads, affiliate links and the paid API — the math itself is never paywalled.
What exactly does the API charge for?
Right now, nothing — the REST API is free during launch. The endpoints run the same deterministic formulas as the free pages; the API adds programmatic machine access with documented per-IP rate limits (free cf_ keys raise them), plus, on Pro, the Graph API, the AI pricing feed and VCC issuance on the pilot formulas. Priced tiers arrive with the first pilots and will be published before they apply.
What is managed VCC?
An enterprise offer we scope together: we operate receipt issuance for you — signing keys (including BYOK/KMS), custom issuer identity, retention policies. The certificate format and verification stay open and free: anyone can check a VCC without paying anything.
Start with the calculators.
Scale when it’s real.
The free tier is the product, not a demo. When your software needs the same math as a service, the API is one key away.