Percentage Decrease Calculator

Find the exact percentage a value has fallen - or calculate the new amount after applying a known percentage decrease.

📉 What is Percentage Decrease?

Percentage decrease measures how much a value has fallen relative to its original amount, expressed as a percentage. It is the standard way to communicate reductions - price discounts, cost savings, weight loss, revenue drops, salary cuts, and test score declines are all typically expressed as percentage decreases. Expressing a fall as a percentage rather than an absolute number makes it comparable across different scales: a ₹5,000 reduction means very different things on a ₹10,000 product versus a ₹5,00,000 product.

The formula divides the reduction by the original value and multiplies by 100. Like percentage increase, percentage decrease is always calculated relative to the original (larger) value, not the new value. This means going from 400 to 300 is a 25% decrease - the ₹100 drop is measured against the original ₹400, giving 25%. If you mistakenly used 300 as the denominator, you would get 33.3%, which overstates the drop.

An important constraint: percentage decrease cannot exceed 100%. A 100% decrease means the value has reached zero - you cannot lose more than the entire original amount. This is in contrast to percentage increase, which has no upper bound. In finance, however, certain derivatives can theoretically lose more than 100% relative to an initial margin - but for everyday calculations, the 100% cap holds.

This calculator covers all three percentage decrease problems: finding the percentage drop between two known values, calculating a new value after applying a known percentage decrease (useful for discounts and markdowns), and finding the original value before a decrease was applied (useful for reverse-engineering pre-discount prices). All three are frequently needed in shopping, business analysis, and health tracking.

📐 Formula

Percentage Decrease = ((Old − New) ÷ Old) × 100

Old = the original or starting value (the larger value)

New = the new or final value (the smaller value)

Result = positive number representing the % fall

Example: Old = 500, New = 350 → ((500 − 350) ÷ 500) × 100 = 30%

New Value = Old × (1 − Percentage ÷ 100)

Use when you know the original value and the percentage decrease, and want the resulting value.

Example: Old = 800, Decrease = 25% → 800 × 0.75 = 600

Original Value = New Value ÷ (1 − Percentage ÷ 100)

Use to reverse a known percentage decrease and find the amount before the reduction.

Example: New = 420, Decrease = 30% → 420 ÷ 0.70 = 600

📖 How to Use This Calculator

Steps to Calculate Percentage Decrease

Select a calculation mode: "Find % Decrease" to measure how much something fell, "Find New Value" to apply a discount or reduction, or "Find Original" to reverse-engineer a pre-decrease price.

Enter your values. Provide the original and new values (Mode 1), or original value and percentage (Mode 2), or new value and percentage (Mode 3).

Click Calculate to instantly see the percentage decrease, the new value, the original value, and the absolute decrease amount.

💡 Example Calculations

Example 1 — Sale Discount

A jacket priced at ₹3,200 is sold for ₹2,240 during a sale

Decrease = 3,200 − 2,240 = 1,060... wait, let's recalculate: 3,200 − 2,240 = 960

Percentage Decrease = (960 ÷ 3,200) × 100 = 30%

Discount = 30% · Saving = ₹960

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Example 2 — Applying a Known Discount

A laptop costs ₹72,000 and is discounted by 15%

New value = 72,000 × (1 − 15 ÷ 100) = 72,000 × 0.85

New value = ₹61,200

Discounted price = ₹61,200 · Saving = ₹10,800

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Example 3 — Finding the Original Price

An item costs ₹1,680 after a 40% reduction - what was the original price?

Original = 1,680 ÷ (1 − 40 ÷ 100) = 1,680 ÷ 0.60

Original = ₹2,800

Original price = ₹2,800 · Saving = ₹1,120

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Example 4 — Weight Loss Progress

Starting weight 90 kg, current weight 76.5 kg

Decrease = 90 − 76.5 = 13.5 kg

Percentage Decrease = (13.5 ÷ 90) × 100 = 15%

Weight reduced by 15% · Lost 13.5 kg

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❓ Frequently Asked Questions

What is the formula for calculating percentage decrease?+

Percentage Decrease = ((Original Value − New Value) ÷ Original Value) × 100. Example: price drops from ₹500 to ₹350: ((500 − 350) ÷ 500) × 100 = 30% decrease. The result is always a positive number when the value has genuinely fallen.

How do I calculate percentage decrease in Excel?+

Use =(A1-B1)/A1*100 where A1 is the original (higher) value and B1 is the new (lower) value. For a general formula that works for both increase and decrease, use =(B1-A1)/ABS(A1)*100 - a negative result indicates a decrease.

What is 20% decrease on ₹5,000?+

20% of ₹5,000 = ₹1,000. New value = ₹5,000 − ₹1,000 = ₹4,000. Shortcut: ₹5,000 × 0.80 = ₹4,000. The multiplier for any X% decrease is always (1 − X/100).

Can percentage decrease exceed 100%?+

No. A 100% decrease means the value has fallen to zero - the absolute maximum possible decrease. You cannot lose more than the entire original amount (in everyday contexts). A 100% decrease on ₹500 gives ₹0; a 110% decrease would give −₹50, which is not meaningful for most physical quantities.

How do I find the original price if I know the discounted price and percentage discount?+

Original = Discounted Price ÷ (1 − Discount% ÷ 100). Example: ₹420 after a 30% discount → original = 420 ÷ 0.70 = ₹600. A common error is adding 30% to ₹420 (giving ₹546) - that's wrong because 30% of the original ₹600 is ₹180, not 30% of ₹420.

What is the difference between percentage decrease and percentage change?+

Percentage decrease is specifically for values that fall, and is always expressed as a positive number. Percentage change is the general case - it is positive for increases and negative for decreases. Use percentage decrease for discounts, losses, reductions; use percentage change when you want a signed result that includes direction.

How do successive percentage decreases compound?+

Two successive 10% decreases do not give a 20% total decrease. After the first: 100 × 0.90 = 90. After the second: 90 × 0.90 = 81. The net decrease is 19%, not 20%. Each successive percentage is applied to the already-reduced value, so the total effect is always less than the arithmetic sum of the individual percentages.

What is 25% decrease on 80?+

25% of 80 = 80 × 0.25 = 20. New value = 80 − 20 = 60. Or directly: 80 × 0.75 = 60. Verify: ((80 − 60) ÷ 80) × 100 = 25%. The 0.75 multiplier is 1 − 0.25 = 0.75.

How is percentage decrease used in business?+

In business, percentage decrease measures cost reductions, revenue drops, expense savings, and headcount changes. Expressing these as percentages rather than absolute numbers makes them comparable across different budget sizes and periods. For example, a 25% cost reduction is equally meaningful whether the absolute saving is ₹5 lakh or ₹50 crore.

How do I calculate the percentage decrease in stock price?+

Percentage decrease = ((Old Price − New Price) ÷ Old Price) × 100. Example: a stock falls from ₹1,500 to ₹1,050: ((1,500 − 1,050) ÷ 1,500) × 100 = 30% decrease. This metric is used in financial reporting, stop-loss calculations, and portfolio risk analysis to measure downside exposure.

🔗 Related Calculators

What is the formula for calculating percentage decrease?

Percentage Decrease = ((Original Value − New Value) ÷ Original Value) × 100. Example: price drops from ₹500 to ₹350: ((500 − 350) ÷ 500) × 100 = 30% decrease.

How do I calculate percentage decrease in Excel?

Use =(A1-B1)/A1*100 where A1 is the original value and B1 is the new (lower) value. Or use =(A1-B1)/A1 and format as Percentage. Example: A1=800, B1=600 → result is 25% decrease.

What is 20% decrease on ₹5,000?

20% of ₹5,000 = ₹1,000. New value = ₹5,000 − ₹1,000 = ₹4,000. Shortcut: 5,000 × 0.80 = ₹4,000.

Can percentage decrease exceed 100%?

No. A 100% decrease means the value has fallen to zero - the maximum possible decrease. Values cannot go below zero in most real-world contexts, so percentage decrease is bounded at 100%.

How do I find the original price if I know the discounted price and percentage decrease?

Original = Discounted Price ÷ (1 − Percentage Decrease ÷ 100). Example: item costs ₹420 after a 30% discount → original = 420 ÷ 0.70 = ₹600. Do not add 30% to ₹420 (that gives ₹546, not ₹600).

What is the difference between percentage decrease and percentage change?

Percentage decrease specifically refers to a value falling, and is expressed as a positive number. Percentage change can be either positive (increase) or negative (decrease). Use percentage decrease for discounts, losses, and reductions; use percentage change for general before/after comparisons.

How do successive percentage decreases compound?

Two successive 10% decreases do not give a 20% total decrease. After the first: 100 × 0.90 = 90. After the second: 90 × 0.90 = 81. Total decrease = 19%, not 20%. Each decrease is applied to a smaller base, so the total effect is always less than the simple sum.

What is 25% decrease on 80?

25% of 80 = 80 × 0.25 = 20. New value = 80 − 20 = 60. Or directly: 80 × 0.75 = 60. Confirm: ((80 − 60) ÷ 80) × 100 = 25%.

How do I calculate the percentage decrease in weight loss?

Percentage decrease = ((Starting Weight − Current Weight) ÷ Starting Weight) × 100. Example: weight drops from 90 kg to 76.5 kg → ((90 − 76.5) ÷ 90) × 100 = 15% decrease. This is more meaningful than looking at absolute kg lost.

What is percentage decrease used for in business?

In business, percentage decrease measures cost reductions, discount amounts, revenue drops, and expense savings. For example, cutting operational costs from ₹18 lakh to ₹13.5 lakh is a 25% reduction - a more comparable metric across different budget sizes than the raw ₹4.5 lakh figure.

📌 Quick Tips

💡Percentage decrease is always relative to the original (larger) value. A drop from 200 to 100 is a 50% decrease - the denominator is 200, not 100.

💡Mental shortcut: to apply a 20% decrease, multiply by 0.80. For 30%, multiply by 0.70. The multiplier is always 1 − (percentage / 100).

💡Percentage decrease cannot exceed 100% - a value cannot fall below zero (you cannot lose more than everything).

💡A 50% decrease followed by a 100% increase returns you to the original value - but a 50% decrease followed by a 50% increase only brings you back to 75% of the original.

💡To reverse a 30% decrease (find original before the discount), divide the discounted price by 0.70, not add 30%.