Percentage Decrease Calculator

Use this percentage decrease calculator to find how much a value has fallen compared with its original value. Enter the starting and final values to calculate the decrease amount, percentage decrease and remaining percentage.

Original Value
New Value

How to Use the Percentage Decrease Calculator

Enter the original value and the lower new value to calculate the percentage decrease.

Practical Example

If a price falls from 200 to 150, the decrease is 25%.

Factors That Affect the Result

The original value is the denominator, so it must be chosen correctly and cannot be zero in a standard calculation.

Frequently Asked Questions

Can the result be negative?

If the new value is higher, the calculation represents an increase instead.

Does order matter?

Yes. The original value must be entered first.

What if the original value is zero?

The standard percentage decrease is undefined.

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How Percentage Decrease Works

Percentage decrease measures how much a value has fallen relative to its original amount. The formula is ((original value − new value) ÷ original value) × 100. If a price drops from 200 to 150, the decrease is 50 and 50 ÷ 200 × 100 = 25%. The original value is the denominator, so percentage decreases are directional. This also explains why increasing a value by a percentage and then decreasing the new value by the same percentage does not usually return to the starting point. For example, 100 increased by 20% becomes 120, and a 20% decrease from 120 gives 96. Percentage decrease is useful for prices, costs, traffic, weight, inventory and other comparisons over time. If the original value is zero, a conventional percentage decrease cannot be calculated because the formula would require division by zero.

Decrease, Remaining Value and Reversal

A 30% decrease leaves 70% of the original value, or a multiplier of 0.70. Reversing that decrease requires dividing the final value by 0.70 rather than adding 30%. This distinction is useful for discounts, depreciation, inventory reductions and other directional comparisons.