Percent Decrease Calculator
Calculate the percentage decrease between any two numbers. Formula: ((Old − New) / Old) × 100. Useful for price drops, salary cuts, weight loss, audience decline, or any value-over-time change.
Reviewed & updated for 2026 · How we calculate
Common percent decreases
| Original | New value | Decrease |
|---|---|---|
| $100 | $90 | 10% |
| $100 | $80 | 20% |
| $100 | $75 | 25% |
| $100 | $70 | 30% |
| $100 | $60 | 40% |
| $100 | $50 | 50% |
| $100 | $33.33 | 66.67% |
| $100 | $10 | 90% |
Common uses for percent decrease
- Pricing & discounts: Sale price = original × (1 − discount%). A $200 jacket marked down 30% = $200 × 0.70 = $140.
- Stock price changes: A stock dropping from $50 to $40 lost 20% of its value.
- Weight loss: 200 lbs to 180 lbs = 10% weight loss.
- Audience or revenue decline: 50K visitors to 35K = 30% decrease in traffic.
- Tax rate reductions: 30% tax bracket lowered to 24% = 20% decrease in marginal rate.
Why a decrease and an increase aren't symmetric
A common misconception: if a price drops 25% and then rises 25%, you're back where you started. You aren't. A 25% decrease on $100 takes you to $75. A 25% increase on $75 takes you to $93.75 — not $100. To recover from the drop, you'd need to gain 33.3% on the lower base.
The asymmetry matters most in investing. A stock that loses 50% needs to double (gain 100%) just to break even. A stock that loses 90% needs to gain 900% to recover. This is why protecting against large drawdowns is so important — you can't math your way back up with average returns.
| If you lose | You need to gain | Real-world example |
|---|---|---|
| 10% decrease | +11.1% | Routine market dip |
| 25% decrease | +33.3% | Bear market correction |
| 50% decrease | +100% | 2008 financial crisis |
| 90% decrease | +900% | Dot-com era flameout |
FAQs
How do you calculate percent decrease?
Formula: Percent decrease = ((Old value − New value) / Old value) × 100. Example: A price drops from $80 to $60. Decrease = ((80 − 60) / 80) × 100 = 25%. Always divide by the ORIGINAL (higher) value, not the new value.
What's the difference between percent decrease and percent reduction?
Same thing. 'Reduction' is more common in everyday language (a 25% reduction in price). 'Decrease' is more common in technical/statistical contexts. Both use the same formula.
Can percent decrease be more than 100%?
Mathematically yes, but practically only if a value goes negative. A stock can't lose more than 100% (it'd be worth less than zero). But a profit can decrease 150% (going from $100 profit to a $50 loss). Most contexts cap at 100%.
How do you reverse a percent decrease?
To find the original value before a decrease: New value / (1 − percent decrease as decimal). Example: A $60 item was discounted 25%. Original = 60 / (1 − 0.25) = 60 / 0.75 = $80.
What is a 30 percent decrease?
30% decrease means the new value is 70% of the old value. Multiply original by 0.70 to get the new value. Example: 30% decrease of $200 = $200 × 0.70 = $140.
How is percent decrease different from percentage points?
Percent decrease is relative. Percentage points is absolute. If interest rate drops from 8% to 6%: percent decrease = 25% ((8−6)/8 × 100), but the drop in percentage points = 2 (8 − 6). News headlines often confuse these, when the Fed cuts rates by 0.5%, that's 0.5 percentage points, not 0.5%.