Thermocouple & RTD batch converter
Turn a whole column of thermocouple voltages (mV) or RTD resistances (Ω) from your DAQ into °C at once. Paste a column copied from Excel, or pick a CSV file.
🔒 Calculated in this browser only — your data never leaves your PC
How it is calculated
- Thermocouples: NIST ITS-90 reference and inverse functions (piecewise polynomials). The cold-junction EMF is added to each reading before solving for temperature. Values outside the table range are flagged.
- RTD: Callendar–Van Dusen equation. Pt100 · Pt500 · Pt1000 use the IEC 60751 coefficients (A 3.9083×10⁻³ · B −5.775×10⁻⁷ · C −4.183×10⁻¹²), including the C term below 0 °C.
- The same coefficients and math the Runplotter program uses to decode thermocouple and RTD channels in NI TDMS files.
Want to see the temperature over time?
Runplotter opens logger and DAQ files (CSV · Excel · NI TDMS · MDF and more) — a whole folder at once — and turns them into per-run charts and an Excel report. A single exe, no install; the free edition has every feature.
Free download →