Precision vs. Accuracy: Why the Difference Matters in Calibration
In regulated industries where product quality, safety, and compliance are non-negotiable, calibration is the silent force ensuring everything works as it should. Yet one of the most misunderstood concepts in the calibration world is the difference between precision and accuracy. These terms are not interchangeable, and understanding the distinction is essential to improving measurement reliability, passing audits, and maintaining operational excellence.
What Is Accuracy?
Accuracy refers to how close a measurement is to the true or accepted value —> it’s about correctness.
Example: If a temperature sensor reads 100 °C when the actual temperature is 100 °C, it’s accurate.
In calibration, accuracy is typically verified by comparing an instrument to a reference standard with a known, traceable value.
What Is Precision?
Precision measures how repeatable or consistent a series of measurements are, regardless of how close they are to the true value.
Example: If a scale gives you the same weight reading five times in a row, it’s precise —> even if that number is slightly off from the actual weight.
Precision is critical for processes that rely on repeatability, such as production-line quality checks or scientific experimentation.
Why the Difference Matters
Many organizations mistakenly believe that a precise instrument is also accurate —> but this is a costly assumption.
A device can be precise but not accurate (consistently wrong).
A device can also be accurate but not precise (correct on average, but inconsistent).
To ensure both, calibration must verify an instrument’s accuracy and assess its ability to produce repeatable results.
Importantly, precision and accuracy are only two of many contributors to a measurement’s overall uncertainty.
Environmental conditions, equipment stability, technician performance, and even reference standard drift can all influence results. This is why partnering with a trusted, accredited calibration provider is essential. They have the expertise, systems, and reference standards necessary to accurately determine and document total measurement uncertainty.
Real-World Implications
In sectors like aerospace, life sciences, and semiconductor manufacturing, misunderstanding accuracy vs. precision can have serious consequences:
- Life Sciences: Inaccurate lab equipment could lead to incorrect dosages, even if measurements are precise.
- Aerospace: A precise but inaccurate sensor could compromise navigation or safety systems.
- Manufacturing: Variability in precision can cause product inconsistencies and increase scrap rates.
How Calibration Solves Both
A well-executed calibration process:
- Aligns instruments with traceable reference standards to ensure accuracy
- Verifies repeatability through multiple test cycles
- Quantifies measurement uncertainty by analyzing all influencing factors — not just precision and accuracy
- Identifies drift over time so teams can intervene before it affects compliance or safety
Precision and accuracy may seem like subtle distinctions, but in the calibration industry, they have major implications. They are also just part of a larger picture — the total measurement uncertainty that defines true confidence in your results. Knowing the difference, and working with a provider who can quantify it correctly, helps teams choose the right tools, interpret results accurately, and uphold the standards their industries demand.
Want to ensure both precision and accuracy — and understand your full measurement uncertainty? Request a FREE calibration quote from our experts today.