Enter your values on the left and click Calculate to instantly see the percentage drop.
The core formula is simple and always the same:
% Decrease = ((Original − New) ÷ Original) × 100
You subtract the new value from the original, divide by the original, then multiply by 100 to convert to a percentage. The result tells you how many units out of every 100 were lost.
Example: A product drops in price from $80 to $60. The drop is $20. Divide 20 by 80 and you get 0.25. Multiply by 100 to get 25%. The price fell by 25%.
If the result comes out negative, it means the value actually increased — not decreased. This tool will flag that for you.
Sometimes you know the current value and the percentage it dropped, but not the original. The reverse formula handles that:
Original = New Value ÷ (1 − % Decrease ÷ 100)
Example: An item now costs $75 after a 25% drop. Divide 75 by (1 − 0.25) = 0.75. The original price was $100.
This is useful for shopping (what was the pre-sale price?), salary negotiations, and any situation where you have the reduced figure but need the baseline.
Use the Find Original mode on this calculator to do this automatically.
How much you pay after applying a percentage drop to common original prices.
| Original Price | −5% | −10% | −15% | −20% | −25% | −30% | −40% | −50% |
|---|
Formula: New Price = Original × (1 − %/100). Values shown are rounded to 2 decimal places.
If you know the current (reduced) value and the percentage it dropped, find the original.
| Current Value | Dropped 5% | Dropped 10% | Dropped 20% | Dropped 25% | Dropped 33% | Dropped 40% | Dropped 50% |
|---|
Formula: Original = Current ÷ (1 − %/100). Useful when you see a sale price and want to know the original.
What happens to a value when the same percentage decrease is applied repeatedly each period.
| Periods | −5% / period | −10% / period | −15% / period | −20% / period | −25% / period | −30% / period | −50% / period |
|---|
Starting value: 1,000. Formula: V × (1 − r)ⁿ. Each period's drop applies to the already-reduced value — totals are not simply additive.
How much you earn annually after different pay cuts applied to common salary levels.
| Annual Salary | −3% cut | −5% cut | −8% cut | −10% cut | −15% cut | −20% cut | Lost / Year |
|---|
"Lost / Year" column is based on a 10% cut. Actual loss depends on your specific cut percentage.
Worked examples from everyday situations — check the math and understand the concept at a glance.
| Situation | Original | New Value | Decrease Amount | % Decrease | Remaining (%) |
|---|---|---|---|---|---|
| 🛒 Black Friday shirt | $80 | $60 | $20 | 25.00% | 75.00% |
| 💼 Salary pay cut | $65,000 | $58,500 | $6,500 | 10.00% | 90.00% |
| 📉 Stock price drop | $240 | $180 | $60 | 25.00% | 75.00% |
| 🏠 House price fall | $420,000 | $378,000 | $42,000 | 10.00% | 90.00% |
| 📝 Test score drop | 95 pts | 76 pts | 19 pts | 20.00% | 80.00% |
| ⛽ Fuel bill drop | $180 | $135 | $45 | 25.00% | 75.00% |
| 🎮 Console on sale | $499 | $349 | $150 | 30.06% | 69.94% |
| ⚖️ Weight loss goal | 220 lbs | 187 lbs | 33 lbs | 15.00% | 85.00% |
| 📊 Website traffic drop | 12,000 visits | 9,000 visits | 3,000 | 25.00% | 75.00% |
| 🔋 Battery life decrease | 10 hrs | 7.5 hrs | 2.5 hrs | 25.00% | 75.00% |
| 💰 Investment loss | $10,000 | $6,200 | $3,800 | 38.00% | 62.00% |
| 🏭 Production drop | 5,000 units | 3,750 units | 1,250 units | 25.00% | 75.00% |
All values calculated using: % Decrease = ((Original − New) ÷ Original) × 100. Use the calculator above to verify or try your own numbers.