# 2 Mechanism To Calculate Percentage Uncertainty & Error

## Calculate Percentage Uncertainty

Is there any problem to understand that how to calculate the percentage uncertainty? It is the superlative content to get the multiple methods. Do not worry about to calculate the percentage uncertainty because, here, in this article, I’m giving you the best method to calculate it.

First of all, before going step-forward to calculate the percentage uncertainty, we will discuss what is percentage uncertainty? So, percentage uncertainty is just the relative uncertainty that is multiplied by 100. It is the ratio of similar quantities which has no units. Percentage uncertainty is denoted by the symbol **“%” **so that you can easily recognize it.

The percentage uncertainty can be illuminate as narrating the uncertainty that will help to give the result if the measured value has 100 units.

### Precision And Accuracy

Before taking the reading to calculate the percentage uncertainty, it is important to check the precision and accuracy of the measuring instrument. So, before all else, you get to know that what is precision and accuracy?

**Precision **

The proximity of the measured values to each other, how much closer they are to each other, means more precise.

**Accuracy **

The nearest measured value to the true value is the accuracy of the measuring instrument.

### How To Calculate The Percentage Uncertainty

There are many situations in which you can calculate the percentage uncertainty. These all are as follows below:

**When You Have Measurement Repetitions**

I will show you the method by giving an example so that it will be trouble-free to understand.

- So, here if we have three reading measurements named, reading 1, reading 2, reading 3. Our average measurement is 5.09.
- The formula to calculate the percentage uncertainty is
**Percentage Uncertainty = half the range/average reading * 100**. - First of all, you have to find out half the range, and its formula is:
**uncertainty = half the range**=**“reading 2 – reading 1 / 2”**. Enter the values to get half the range. - Then enter the value of half the range into the given formula of percentage uncertainty.

**When You have No Measurement Repetitions **

There is another method to calculate the percentage uncertainty when there is no more than one reading on the measuring meter. Follow the steps below:

- Calculate the reading on the meter
- Then calculate the resolution to find its value to enter in the actual formula
- First of all, find out half of the resolution. Its formula is:
**Uncertainty = Resolution/2.** - Then put the value of half of the resolution in the given formula of percentage uncertainty. The formula of percentage uncertainty is
**Percentage uncertainty = half-resolution/meter reading taken * 100.**

Sometimes, the measurements could be the same that has been taken by you with no variation or range. What I mean to say is that absolute uncertainty turns out to be 0! So then we take the resolution to calculate the percentage uncertainty. Resolution is the smallest measurement.

There are some devices that has different resolutions:

- Meter Rule: 1mm
- Vernier Caliper: 0.01mm
- Micro Meter: 0.01mm

**Measurement Errors**

The actual value is the value that you obtain from experiments in different or ideal conditions. It is sometimes going to be different from the measured value, so, the difference between the actual value and measured value is a measurement error that helps you to get the basic error in your measurements.

These are the basic methods to measure or calculate the percentage uncertainty in an effortless way.