Legal
FrameCalc is educational software. Results are for study and comparison, not medical, radiation-protection, or engineering sign-off. Fusion tools are models, not device predictions.
Terms of use
FrameCalc is educational software. Check results against a textbook or your own derivation. Pro unlocks on this device after Gumroad verifies your receipt license. Each purchase includes up to three browser activations; deactivate here before moving to a new device. Do not publish your license key. Keep your Gumroad receipt.
Privacy
Calculations run in the browser. History and Pro flags are stored in localStorage on this device. License activations (browser seats) are stored in a server database keyed by a hash of your license — not your calculator inputs. Gumroad sees checkout data only.
Fusion tools
Bosch–Hale and Child–Langmuir are published formulas with stated limits. The IEC yield tool is a beam-target order-of-magnitude estimate, not a device or survey prediction.