Percentage Decrease Calculator

Find the percentage drop between two values, calculate a new value after a decrease, or reverse-calculate the original. Three modes for every scenario.

Original Value

New Value

Percentage Decrease

-20.00%

Absolute Decrease -20.00

Formula & Examples

Core Formula

% Decrease = ((Old Value − New Value) ÷ Old Value) × 100

New Value = Old Value × (1 − Decrease% ÷ 100)

Original Value = New Value ÷ (1 − Decrease% ÷ 100)

Scenario	Old	New	Decrease
Price drop	200	160	−20%
Weight loss	180 lb	153 lb	−15%
Sales decline	5,000	3,500	−30%
Temperature drop	80°F	64°F	−20%

Frequently Asked Questions

How do I calculate percentage decrease? ▼

Subtract the new value from the old value, divide by the old value, then multiply by 100. Formula: ((Old − New) ÷ Old) × 100.

What is the percentage decrease from 100 to 80? ▼

((100 − 80) ÷ 100) × 100 = 20%. The value decreased by 20%.

How do I find the new value after a 15% decrease? ▼

Multiply the original value by (1 − 0.15) = 0.85. Example: 200 × 0.85 = 170.

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

Percentage decrease always returns a positive number representing how much a value dropped. Percentage change is signed (+/-) and works for both increases and decreases.

Can I find the original value if I only know the decreased value? ▼

Yes — use "Find Original" mode. Enter the decreased value and the percentage it decreased by. Formula: Original = New Value ÷ (1 − Decrease%/100).

Related Percentage Calculators

→

Percentage Change Calculator

Calculate both increases and decreases between any two values

→

Percentage Calculator

Versatile percentage math — find value, percent, or base number

→

Percentage Off Calculator

Find the discounted price and savings from a sale percentage