σT

σT is a precision tool for physics students and researchers who need to propagate measurement uncertainties through calculations. Enter your experimental data, and σT handles the error math automatically.


**FIVE ERROR MODES**

Configure uncertainties in your data to match your orignal measurement method:
• Constant — for physical constants and exact values
• Absolute — fixed ±error (ruler measurements, digital readouts)
• Relative — percentage-based uncertainty
• Combined — both absolute and relative components (many typical multimeters)
• Per-Value — individual error for each measurement


**AUTOMATIC PROPAGATION**

Create derived values and watch uncertainties flow through the calculation chain. σT uses Gaussian error-propagation and pre-calculated derivative-based methods to compute propagated errors correctly when combining independently measured variables.

Available operations:
• Basic: add, subtract, multiply, divide, reciprocal
• Functions: exp, ln, sin, cos, normalize
• Statistical & Sample Statistics: mean with standard error, average step width
• Advanced: weighted sums, weighted products, polynomials
• Physics: Lorentz factor (relativistic gamma), Logit sigmoid (Fermi-Dirac statistics)


**INTERACTIVE CHARTS**

Visualize your data with proper error bars. Pinch to zoom, drag to pan, double-tap to auto-fit. Add mathematical function overlays to compare your measurements against theoretical predictions, identify eligible parameter ranges matching your measurements.


**EXPORT YOUR WORK**

• CSV and TSV export for spreadsheets and analysis tools
• High-resolution PNG charts for lab reports
• Complete project files for sharing with classmates or colleagues
• Copy data to clipboard with a swipe and continue in Sheets or Excel with errors in place


**DESIGNED FOR LAB WORK**

σT adapts to your device:
• iPhone: Full-featured portable lab companion
• iPad: Side-by-side layout for efficient data entry
• Mac: Native desktop experience via Catalyst


**YOUR DATA, YOUR DEVICE**

All measurements are stored locally. No account required, no cloud sync, no tracking. σT works completely offline.