How to Calculate Instrument Error? VC480C+ Multimeter Accuracy & Resolution Formula

Many engineers and technicians struggle with instrument error calculation, often making mistakes due to misunderstanding accuracy parameters. This guide breaks down the correct method with step-by-step examples using the Vicimeter VC480C+ milliohmmeter, and provides a universal formula applicable to all types of test instruments.

Before calculating error, it is critical to clarify three core parameters to avoid fundamental confusion:

Facing these indicators, did you ever have such doubts? In the accuracy “±（0.5%×digits+3)”, how do we calculate the “3”. 

Have a try with the 20mΩ range, when the input is 10.00， how will you calculate the error?10.00+(10.00× 0.5%+3)=10+3.05=13.0510.00-(10.00× 0.5%+3)=10-3.05=6.95

So the error margin is 6.95Ω-13.05Ω？

Is It Correct?NO！！！

So what is correct way? Don't worry！

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This formula is not limited to milliohm meters. It can be applied to all Vicimeter test instruments (VC4060, VC700, VC80 and CM20 Series, etc.) and all instrument types, including:

Digital multimeters (DMM)；

Clamp meters；

Temperature meters (thermometers)；

Illuminance meters (lux meters)；

Any electronic test instrument with ±(% reading + N) accuracy specifications.