How to Calculate Order of Magnitude

How to Calculate Order of Magnitude
••• PhotoBylove/iStock/GettyImages

Order of magnitude calculations are an important skill to develop. These calculations are a way of estimating specific quantities, which might be difficult (or impossible) to find an exact value for. By making an intelligent estimate, it is possible for you to find a quantity with enough accuracy to be useful for practical purposes, especially if it is sufficient to have a value that is within a certain percentage of the actual value (for instance, 10 percent).

    Identify the quantity you would like to estimate. For example, assume you want to fill a swimming pool using a garden hose, and you would like to know how long this would take. The important quantity here is the amount of time to fill the pool.

    Determine any important intermediate values, which are important for the final estimate. In our example, such quantities include the volume of the swimming pool and the flow rate of the garden hose.

    Identify any calculations that will help you find the intermediate quantities. For example, to find the volume of the swimming pool, you need to know the approximate length, width and depth of the swimming pool.

    Identify anything that relates the intermediate quantities to the desired final quantity. In the example, you can find the time it takes to fill the swimming pool by dividing the volume of the swimming pool by the flow rate of the garden hose.

    Round the answer to the nearest order of magnitude (i.e. the nearest power of 10). For example, assume the time to fill the swimming pool, based on your calculations, is 787,443 seconds. Rounding this to the nearest order of magnitude gives 1,000,000, or 10 to the power of 6. This provides a rough estimate as to how long it would take to fill the swimming pool and shows that the time is closer to 1,000,000 seconds than 100,000 seconds.

    Things You'll Need

    • Paper
    • Pen or pencil


    • Ensure your estimates are realistic. For example, if you are estimating the weight of a penny, don't assume the weight is 100 pounds.

Related Articles

How to Convert Seconds Into Miles Per Hour
How to Find the Midpoint of the Interval
How to Calculate Percent of Return
How to Calculate Moles
How to Calculate the Rate of Decay
How to Solve for Range
How to Calculate Water Volume
How to Solve Percentage Problems
How do I Calculate 0.1%?
How to Calculate a Growth Trend
How to Read a Time Clock in Hundredths of an Hour
How to Calculate Percent Relative Range
How to Calculate Rate of Decrease
How to Find the Area & Width of a Rectangle
How to Find Y Value for the Slope of a Line
How to Calculate Daily Compounding Interest
How to Find Euclidean Distance
How to Calculate Incline
How to Solve a Time in Flight for a Projectile Problem
How to Calculate the Percentage of a Number

Dont Go!

We Have More Great Sciencing Articles!