Pricing
FrameCalc is a browser toolkit for special-relativity kinematics, teaching simulations, and standard fusion formulas — with plots and LaTeX copy. Pro adds PDF export, named workspace, parameter sweeps, dataset-fit export, MATLAB / Wolfram / NumPy snippets, a course-pack JSON file, and a local history notebook.
Free
$0 / forever
- Kinematics workbench (collisions, decays, Lorentz, Compton, Doppler)
- Teaching simulations (Kepler, Schwarzschild, TDSE, Ising, and others)
- Fusion formulas (Bosch–Hale, Child–Langmuir, Coulomb barrier, labeled yield)
- Optics, lab, signals, and the rest of the library
- Copy as LaTeX · Natural / SI display · shareable URLs
Pro
$39 / one-time
Buy on Gumroad. The receipt license looks like ABCD1234-EFGH5678-IJKL9012-MNOP3456. Paste that here — not the product id from the Gumroad dashboard. Each license works on up to 3 browsers. Do not share your key publicly.
- PDF export: results, values, and the on-page figure when one exists
- Named workspace — 20 saved input sets in this browser
- Parameter-sweep grid (cap 200) plus raw CSV batch
- Dataset bench: linear, polynomial, power, and exponential fits (export is Pro)
- MATLAB / Wolfram / NumPy snippets (same recipes as the CAS suite)
- Course-pack JSON (10 cases with kernel-computed check values)
- Local history of Lorentz, collision, and decay runs (this browser)