Simple, Transparent Pricing
All calculators are free forever. Upgrade for a better experience and extra power.
Free
Everything you need to get started with RF engineering calculations.
- ✓All 197+ calculators
- ✓Educational content
- ✓Shareable URLs
- ✓Embeddable widgets
- ✓Mobile + offline (PWA)
- ✓API access — 5 calls/month
- ✓1 API key
Pro
For engineers who want a distraction-free experience and cloud sync.
- ✓Everything in Free
- ✓No advertisements
- ✓Save calculations to cloud
- ✓Export results as CSV
- ✓Priority support
- ✓New calculators first
- ✓API access — 100 calls/month
- ✓3 API keys
API
Integrate RF calculations directly into your own apps and workflows.
- ✓Everything in Pro
- ✓10,000 API calls/month
- ✓5 API keys
- ✓Batch endpoint (up to 50 calculations)
- ✓OpenAPI / Swagger docs
- ✓API key management dashboard
- ✓Usage analytics
Frequently Asked Questions
Can I cancel anytime?
Yes, cancel from your Lemon Squeezy dashboard — no questions asked. Your Pro access continues until the end of the billing period.
What payment methods are accepted?
Lemon Squeezy accepts all major credit/debit cards, PayPal, and regional payment methods. No account registration required to purchase.
Is there a free trial?
There's no time-limited trial, but the Free tier gives you full access to all calculators. Upgrade to Pro when you need the additional features.
How does the API work?
Every signed-in user gets API access — Free (5 calls/mo), Pro (100 calls/mo), and API (10,000 calls/mo). POST to https://rftools.io/api/py/v1/calculate with your API key in the X-API-Key header. Quotas reset on the 1st of each month. Full documentation is available in your dashboard.
What happens to my API keys if I downgrade?
Your keys stay active — only the monthly quota adjusts to your new plan. No surprise revocations.
Do you offer team or site licenses?
Contact us at api@rftools.io for volume pricing on API access.
Payments are processed securely by Lemon Squeezy. Questions? Email api@rftools.io