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How To Reduce Uncertainty In Measurement

By | Ewan Webster |

Reducing the uncertainty in measurements has become a goal for many laboratories for improving the measuring quality. Whether it also helps to enhance their laboratory reputation or to make themselves more competitive in the marketplace. Remember that it is as important to reduce uncertainty as to quantify uncertainty in measurements. To minimize uncertainty you can use different methods or an online calculator such as,  significant figure calculator that helps you to determine which number is significant, how many significant figures a number have, and decimal number. 

There are some good recommendations given below that will surely help you reduce the uncertainty:

  • Choose the best instrument for measurement and use calibration facilities with a minimum number of errors.
  • Validate the measurements by checking them repeatedly or use other kinds of validation methods. Checking calculations in various ways will be best of all.
  • Check the calculations where the numbers are copied from one place to another.
  • Use an uncertainty budget to know about the worst uncertainties.
  • Calibrate the measuring of the instruments and use the calibration correction which are given on the calibration report or certificate.
  • Make corrections to overcome the risk of uncertainty.
  • Make measurements traceable to the national standards by using the calibrations. Which can be traceable to national standards by an unbroken chain of measurements.
  • Beware about the successive chains of calibrations where the risk of uncertainty increases at every step of the chain.

Some other measurement recommendations:

  • Follow the instructions by the maker regarding the maintenance and use of instruments.
  • To make sure that it works well, you need to check the software.
  • Prefer the experienced persons and provide training for taking measurements.
  • Use rounding in the calculations correctly.
  • Keep the record of the measurements and calculations that you have taken and write down the readings at the time of taking measurements. Also keep the record of extra information relevant to the measurements. If the measurements will be taken into account at any time, then these records will help you.

Use of calculators:

When you are using calculators and computer programs then you need to know how to avoid errors when using them. Using calculators and online applications made it easier to perform mathematical operations and experimental calculations. 

Estimating the uncertainty in the chemistry lab is different as compared to other laboratories. Mostly chemistry labs use different processes and calculators to measure the uncertainty. 

You can give a try to an online significant figures calculator that helps you to determine any number or expression into a new number with a number of significant figures.

Calculator and software errors :

A calculator is useful to perform arithmetic operations but it can be the source of making errors. Sometimes they give unexpected errors when doing calculations with very large numbers. For example, some calculators give wrong estimates:

                        0.000 000 3 × 0.000 000 3 = 0 (exactly),   

When the correct answer is 0.000 000 000 000 04. It can also be represented as 3 X 10-7     X   3 X 10-7 = 6 X 10-7. Even computers also suffer sometimes from these kinds of errors.


Before dealing with the specific rules that are used to determine the significant figures in a calculated result, we need to learn how to round numbers correctly. When rounding a number, decide how many significant figures a number have. After knowing about the figures then round to a certain degree of significant digits and the number which is following that degree is less than five, the last sigfig is not rounded up and if it is greater than it  is rounded up.


A)5880 rounded to four significant figures is 20.59.

B)6860 rounded to four significant figures is 10.68.

Sigfig calculations become simpler and easier with the use of an online significant calculator that allows you to figure out the uncertainties of measured quantities. 

Significant figures operations:

Addition and subtraction

Figure out the total uncertainty while adding or subtracting two quantities with their uncertainties by adding the by adding the absolute uncertainty.

For Example:

(4.3 ± 0.2 cm) + (3.1 ± 0.1 cm) =(4.3 + 3.1) ± (0.2 + 0.1) cm = 7.4 ± 0.3 cm

(4.3 ± 0.2 cm) – (3.1 ± 0.1 cm) =(4.3 – 3.1) ± (0.2 + 0.1) cm = 1.2 ± 0.3 cm

Multiplying or dividing:

When quantities are multiplied or divided with their uncertainties then you can add relative uncertainties together.

For Example:

(4.3 cm ± 5.0%) × ( 2.0 cm ± 3.0%) = ( 4.3 X 2.0) cm2 ±  (5.0 + 3.0)% = 8.86 cm2 ± 8%

(4.3 cm ± 5.0%) ÷ ( 2.0 cm ± 3.0%) = ( 4.3 ÷ 2.0) cm2 ±  (5.0 + 3.0)% = 2.15 cm2 ± 8%

An online significant figure calculator can be used to turn any number or expression into a new number with the desired number of significant figures.

How to Find Sources of Uncertainty?

To find the resources about the analysis of measurement, follow the below listed step:

  1. Evaluate the methods of testing, calibration, or measurement process.
  2. Estimate the measurement equations, if available and equipment, and reference standard.
  3. Classify the minimum sources of uncertainty.
  4. Search on various sources of information.
  5. Consult with an expert.


Quantities can be measured and measured quantities have uncertainty that is expressed by the number of significant figures in the calculations. The uncertainty of calculations can be avoided by reporting the results of measurements with the correct number of sigfigs. So, you can use sig fig counter that helps you to determine the amount of significant figures in a number and even find the number that is significant.



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