Calibration Certificate Correction Calculator
Use the results from a calibration certificate to correct readings: enter the certificate points (nominal value and error), and the calculator interpolates the correction at your reading.
- Error = e₁ + (e₂ − e₁) × (x − x₁) ÷ (x₂ − x₁) = 0.08 + (0.06 − 0.08) × (120 − 100) ÷ (150 − 100) = 0.072
- Corrected value = reading − error = 119.928
Certificate Correction
e(x) = e₁ + (e₂ − e₁) × (x − x₁) ÷ (x₂ − x₁)
Corrected value = reading − e(x)
The certificate lists the error of the instrument (indicated value minus reference) at each nominal point. Between points, linear interpolation estimates the error. Check the sign convention on your certificate: some list the correction (reference minus reading) instead, which is added.
Worked example
With the certificate shown, a reading of 120 lies between 100 (+0.08) and 150 (+0.06): error = 0.072, so the corrected value is 119.928.
Frequently Asked Questions
What is the difference between error and correction?
Error is reading minus true value; correction is the negative of the error, the amount to add to the reading.
Can I extrapolate beyond the certificate?
Not reliably. The certificate only covers the calibrated range; outside it the instrument is not traceable.
Should I apply corrections to process instruments?
Usually you adjust process instruments instead. Corrections are mainly used for reference standards and test equipment.
Learn more on the blog
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