Pricing
Free to calculate. Pro to keep.
The calculators, formulas, examples and sources are free with no account. Pro is for people who come back: it remembers your scenarios, exports your results and removes the ads.
Plans
Free
$0
- Every calculator
- Formula, worked example and dated sources
- Shareable result links
- Advertising on tool pages
ProRecommended
$9per month
- Everything in Free
- Save and reload scenarios on every tool
- Export results as CSV or JSON
- Compare every model side by side
- No advertising
- Email support
Prices in US dollars. Polar is the merchant of record and adds tax where it applies. Cancel any time; the licence runs to the end of the paid period.
How does Pro switch on?
Polar emails a licence key at checkout. Paste it on the Pro page; the browser remembers it. Use the same key on every device.
Where are saved scenarios stored?
In your browser's local storage. Nothing is uploaded, so clearing site data clears them. Export to CSV or JSON for a copy.
Refunds?
Within 14 days of purchase, by replying to the Polar receipt email or through the support form.
Is there a team plan?
Not yet. Ask through the support form if you need several seats.
Checkout is handled by Polar, which processes payment and collects tax as the merchant of record. Norwell Systems LLC never sees card details.