Use this percent decrease calculator to easily calculate the result from a percentage decrease by any amount. Show
Quick navigation: Percent decrease calculations are needed when comparing time periods, estimating percent decline (yearly, monthly, daily etc.), or comparing a new state to an old state of things. An example would be a discounted price versus an original price, usually during sales and promotions, or when you are offered a percent off the regular price of a product or service. A less fortunate circumstance would be a pay cut or salary reduction situation. Percent decrease formulaThe formula for calculating percent decrease used in our percentage decrease calculator is: Percent decrease = 100 - new / old * 100 where new is the newer quantity or measure, and old is the older quantity or measure. Let us see some examples to see how that works. In other cases, you know the starting, or original quantity, measure, or price, and you want to estimate what it would be if it were decreased by a given percentage. Then the formula is: Decreased value = base - base * % decrease / 100 where base is the starting amount and % decrease is the percentage to reduce it by. Let us see some examples to see how it works. Examples of calculating percent decreaseA few practical examples should illuminate the use of percent reduction calculations in various settings and how to work out the math. Example: new versus old priceLet us say you walk into a store and you see a 30% discount on an item due to a sale, promotion, or maybe you have a 30 percent off coupon you can use. Now, if you see that the original price is $100, how do you estimate the final price you need to pay? You use our calculator in the "decrease X by Y" mode, or you can calculate it manually by plugging the numbers into the second formula above to get $100 - $100 x 30 / 100 = $100 - $100 x 0.3 = $100 - $30 = $70 final price after decreasing it by the percent off. If, however, you know the old price was $100 and the new price is $70, and you want to calculate the percent decrease, then you use the first formula: 100 - $70 / $100 * 100 = 100 - 0.7 * 100 = 100 - 70 = 30% decrease. Decrease in expenses exampleIn this example use case of our percent reduction calculator, you run a company and you have attempted to limit your expenses in order to stay cash positive. In the previous year you incurred expenses of $500,000 during the same time period, while this year you only have $400,000 in outlays. What percent reduction have you achieved? To calculate the decline in expenses, divide the current expenses by the prior expenses: $400,000 / $500,000 = 0.8, then multiply by 100 to get 80, then subtract that from 100. The final result is that you have managed to decrease your expenses 20% year over year. In another scenario your accountant has told you that you need to decrease your start-ups capital burn by 40% if you want to make it to the end of the year. Last month you spent $50,000, how much should you spend next month to meet the 40% target? Using the second formula, you calculate that you need to stay below $50,000 - $50,000 * 40 / 100 = $50,000 - $50,000 x 0.4 = $50,000 - $20,000 = $30,000 a month to stay afloat. In other words, decreasing your burn rate by 40% equals reducing it to $30,000 a month. Calculate revenue or salary after taxesYou might want to calculate your after-tax salary (net salary), or after-tax revenue (net revenue), knowing your pre-tax yearly salary or revenue is $80,000 and that your total tax rate is 42%. You can, of course, use our percentage decrease calculator in the "X decreased by Y%" mode, or you can decrease $80,000 by 42% yourself like so: $80,000 - $80,000 * 42 / 100 = $80,000 - $80,000 x 0.42 = $80,000 - $33,600 = $46,400 net salary / net revenue. The example works out to a pay reduction of close to thirty-four thousand dollars. Example: decrease in body mass (weight)Your general practitioner has told you that you need to lose 5% of your weight in order to keep your body in a healthy condition and you want to know how many pounds (or kg) you need to lose. You currently weigh at 200 pounds, so you can just plug that into our percent decrease calculator, or by using the second formula calculate that you need to get to 200 - 200 * 5 / 100 = 200 - 10 = 190 pounds to be in good health. Say you are trying to lose weight in order to get to your healthy weight range, and your average weight for a few weeks was 160 pounds. However, today the scale shows that you weigh only 150 pounds and you want to know what percentage increase it represents. Of course, it is easiest to use our online percentage decrease calculator, but if you want to do the math by hand, it is 100 - 150 / 160 * 100 = 100 - 0.9375 * 100 = 100 - 93.75 = 6.25 percent decrease in body weight. CALCULATOROur percent calculator uses this formula:((y2 - y1) / y1)*100 = your percentage change (where y1=start value and y2=end value) How to use our FREE Percent Change Calculator It is very simple, easy and quick to use!Step 1: Simply fill in the initial and new values in the provided boxes.Step 2: Hit the “calculate” buttonStep 3: You’ll get your percentage change in a twinkle of an eye!Percentage Change Formula (New Value - Initial Value)/(Initial Value) * 100 = percentage increase or decrease1. Calculate the percentage increase of the rent If the monthly cost of renting an apartment is $789 in June and the landlord has decided to charge a new price of $807.46 in the month of July. Calculate the percentage increase in the rent between June and July.(807.46 - 789) / 789 × 100 = 18.46 / 789 × 100 = 2.339Your rent has increased by 2.34%. We can verify that: 789 × 1.0234 = 807.462. Calculate the production decline in percentage The production of a company diminishes from 2345 pieces per day to 1870 pieces per day. What is the percentage decrease in production of this company?(1870 - 2345) / 2345 × 100 = −20.256The decrease in production is equal to -20.26%. We can verify that: 2345 × (1 - 20.26 / 100) = 2345 × 0.7974 = 1870 rounded to the nearest unit.3. How to determine the percentage of a reduction A seller gives you a discount of 30 USD on a household electrical appliance to 210 USD. What is the percentage reduction? You will pay 180 USD instead of the 210 USD requested. The tool gives us:(180 - 210) / 210 × 100 = −14.29. The change from 210 to 180, in percentage, represents a decrease of -14.29% of 210.We can verify that: 210 x (1 - 14.29 /100) = 210 x 0.8571 = 180.4. Calculate the evolution in percentage of negative values In order to calculate the change in percentage on negative values, one must take the absolute value of the initial value:(new-old) / |old|.A temperature drops from -20 degrees Fahrenheit to -45 degrees Fahrenheit. What is the percent change?(-45 - (-20)) / 20 * 100 = 125The temperature has dropped by 125%.We can verify: 125% of 20 degrees Fahrenheit represents 25 degrees Fahrenheit. This gives -20 - 25 = -45 degrees.Other percent calculationsThese free calculators compute a number of values involving percentages. 1. Percent change: increaseIn this chapter we examine what a percent increase is.ExampleDad weighted 75 kg before the holidays. When he returned, his weight had increased by 5%. How much does Dad weigh now?75 + 5% * 75 = 75 + 3.75 = 78.75 kgThe percent increase is the increase, expressed in percentage, of a quantity over time.Initial Value ± percentage of change = final valueExample (continued)We can simplify the operation 75 + 5% * 75 by factoring. Therefore:75 + 5% * 75 = 75 * (100% + 5%).In doing so, we find the following percent change (100% + 5%)Initial Value Vi * multiplication factor q = Final Value VfThe Percent change in a percentage notation: q=(100%+p%)The Percent change in a decimal notation: q=(1+p/100)Terms such as "increase", "growth", "rise" can help you identify that it is a matter of calculating a rate of increase. If you know two of the three values (initial value, multiplication (percentage) factor, final value), then you can easily find the third one. To do this, simply apply the above equation (with the value to be found on the left side). 1.1. Calculating the final value Vf = Vi * qExampleA smartphone of the “Pear” brand costs $300.Given the increase in demand, the manufacturer increases the price by 25%.How much does the smartphone cost after the price increase?Vf = 300 * (1 + 25/100) = 300 * (1 + 0.25) = 300 * 1.25 = 375After the price increase, the smartphone costs $3751.2. Calculating the initial value 1.3. Calculating the Percent change q = Vi / VfExampleThe smartphone manufacturer increases the price of the smartphone from 300$ to 375$. By what percentage has the price increased?q=375/300=1.25The price increased to 125% of the initial price.2.1. Calculating the final value Vf = Vi * qExampleA smartphone of the “Pear” brand costs $300.Given the decrease in demand, the manufacturer lowers the price by 25%. How much does the smartphone cost after the price decrease?Vf = 300 * (1 - 25/100) = 300 * (1 - 0.25) = 300 * 0.75 = 225After the price decrease, the smartphone costs $225.2.2. Calculating the initial value Vi = Vf * qExampleAfter a 25% decrease from its initial price, the smartphone now costs $225. How much did the phone cost before the price decrease?Vi = 225(1+25/100)=225(1+0,25)=225*1,25=300Before the price decrease, the smartphone cost $300.2.3. Calculating the percent change q = 1 - Vi / VfExampleThe smartphone manufacturer lowers the price from $300 to $225. By what percentage has the price decreased?q=1-225/300=1-0.75=0.25The price decreased by 25% from the initial price.3.1. Percentage increase and decrease of the same percentage Contrary to popular belief, if a starting value increases by p % and then decreases by the same percentage, this does not lead to the starting value. This also applies to a decrease of p% and then an increase of the same percentage.ExampleThe price of a product costing $50 increases by 10%Vf=50⋅(1+10/100)=50⋅(1+0,1)=50*⋅1,1 =55After the price increase, the product now costs $55. We now lower its price by 10%.Vf−=55⋅(1-10/100)=55⋅(1-0,1)=55*⋅0,9 =49,5The product now costs $49.5 rather than $50 as one might have expected.3.2. The percent change of a percentage The change of a percentage can be written in percentage or in percentage points.ExampleThe XYZ party scored 20% in previous elections, and got 30% of the vote in today’s elections.Saying that “the XYZ party got 10% more votes compared to previous elections” is erroneous! An increase of 10% would only result in 22% of the vote in today’s elections.20⋅(1+10/100)=20*⋅1.1=22The absolute variation between two percentages is given in percentage points.Example (continued)30-20=10The XYZ party scored 20% in previous elections, and got 30% of the vote in today’s elections.Saying that “the XYZ party got 10% more votes than in the previous elections” is erroneous! An increase of 10% would only result in 22% of the vote in today’s elections.20⋅(1+10/100)=2*0⋅1.1=22The absolute variation between two percentages is given in percentage points.Example (continued)30-20=10In today’s elections, the XYZ party got 10 percentage points more votes than during the previous elections.The relative change between two percentages is given in percent.Example (continued)Initial value V : 20 (initial percentage)Percentage value P : 10 (absolute variation)p = P/V= 10/20 = 0.5In today’s elections, the XYZ party received 50% more votes than in the previous elections.5.1. Calculating a multiplication factor (from a percentage) If the percentage p% is given, the multiplication factor is calculated as follows:Increase: q=(1+p/100)Decrease: q=(1-p/100)Example 1Increase of 30 %: p%=30%⇒q=(1+30/100)=1+0.3=1.3Example 2Decrease of 20 % : p%=20%⇒q=(1-20/100)=1-0.2=0.85.2. Calculating the percentage (from a multiplication factor) If the multiplication factor p% is given, the percentage is calculated as follows:multiplication factor > 1: p%=q-1multiplication factor < 1: p%=1-qExample 1Increase to 160 %: q=1.6⇒p%=1.6−1=0.6=60%Example 2Decrease to 30 %: q=0.3⇒p%=1−0.3=0.7=70%You find more information about this subject here: wikipedia |