Pricing
Free calculators.
Infrastructure for every scale.
Every calculator on this site is free and stays free. The paid plans cover one thing: programmatic access — the REST API, the data feeds, certificate issuance. Prices live where billing lives, on RapidAPI; this page never invents a number.
Free
Free forever
Everything a person needs. The math is never paywalled.
- All 121 web calculators
- Embeddable widget, with attribution
- Public MCP server for AI agents
- VCC certificate verification
- No account, no trial clock
Developer
Billed through RapidAPI
The same deterministic math, as a service for your software.
- REST endpoints for all 121 calculators
- Zod-validated inputs, JSON in / JSON out
- OpenAPI spec and documentation
- Keys, metering and billing via RapidAPI
- Documented platform rate limits
Pro
Billed through RapidAPI
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 | Via RapidAPI | Via RapidAPI | 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 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. Per-plan quotas are metered and enforced by RapidAPI and published on the listing.
The web Copilot is free for everyone with a daily limit of 15 prompts; an access pass removes the limit.
Where the actual prices live
API plans are billed through RapidAPI: tiers, quotas and the definitive prices are published on the listing, not improvised here. 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 121 web calculators, the embeddable widget, the public MCP server and VCC certificate 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?
Programmatic access. The REST endpoints run the same deterministic formulas as the free pages; what you pay for is metered machine access — keys, quotas and billing handled by RapidAPI — plus, on Pro, the Graph API, the AI pricing feed and VCC issuance on the pilot formulas.
What is managed VCC?
An enterprise offer we scope together: we operate certificate 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.