We build the tool we wanted in the lab: fast, transparent and free — with the method visible at every step.
Determining an optical band gap from UV–Vis data is a routine measurement with an awkward workflow: export the file, clean it in a spreadsheet, guess the linear region, fit it twice, argue about the exponent, and re-plot everything for the figure.
Tauc Plot Calculator collapses that loop into one page. Import the raw export, declare the units, choose the transition model and adjust the fit window — the regression, the intercept and the plot update as you drag. Nothing is uploaded, nothing is stored, and nothing needs installing.
We keep the physics on the surface rather than behind a button: the exponent, the fit window, R² and the extrapolation are all visible while you work, because a band gap you cannot defend is not much of a result.
Spectra are scientific data — often unpublished, sometimes proprietary. Every computation runs locally, so no file is ever transmitted, stored or logged.
No black boxes. The Tauc relation, the exponent you selected, the fit window and the regression statistics are all visible while you work.
Automatic parsing and fit proposals are starting points. Every parameter — units, exponent, thickness, fit window — remains under manual control.
No accounts, no credits, no paywall. The calculator is meant to be used in lab courses, group meetings and publication workflows alike.
Turn a UV–Vis export into a manuscript-ready Eg value with the statistics reviewers expect to see.
Compare batches and compositions quickly, with consistent unit handling across every sample.
Demonstrate the Tauc method interactively using the bundled sample datasets — no software install required.
Run a repeatable, documented check on incoming thin films and powders straight from the browser.
Parsing, unit conversion, least-squares regression and rendering all execute in the browser. There is no backend to breach, no queue to wait in, and no dataset to delete.
The implementation follows Tauc (1966), Davis & Mott (1970) and the practical guidance in Makuła et al. (2018). Every equation used is documented on the methodology page.
Results depend on your sample, your instrument and your fit window. Always validate against known references before reporting a value — the responsibility for the number stays with the analyst.
We read everything that comes in — including bug reports about stubborn instrument exports.