What is the Percentage Decrease Calculator?
The jacket was $200; the sale tag says $150. The $50 you keep is nice, but the percentage tells you whether the deal is actually good — and that's the percentage decrease: the drop divided by the original, times 100. Here it's 50/200 = 25% off. Retail runs on this number (every "25% OFF!" sign), and so do investors watching a stock slide, dieters tracking weight loss, and cities measuring falling crime rates. The original value is always the denominator — the "before" picture is the reference point, never the "after."
The trap is picking the wrong base. Dropping from $200 to $150 is a 25% decrease, but climbing back from $150 to $200 is a 33.3% increase — asymmetric, because the reference changed. This calculator keeps the bookkeeping straight: enter the Original Value and the New Value, and read the Absolute Decrease ($50), the Percentage Decrease (25%), and the Value Retained (75% — the share of the original that remains). The retained figure is the unsung hero: a "30% off" sale means you keep paying 70%, and seeing both numbers side by side is how you comparison-shop honestly.
With the pre-filled defaults — Original Value 100, New Value 80 — the Percentage Decrease Calculator returns Absolute Decrease 20.0000, Percentage Decrease (%) 20.0000, Value Retained (%) 80.0000. Change any input and those results update instantly, so you can see exactly how each number you enter moves the answer.
How to Use the Percentage Decrease Calculator
- 1Type the starting amount in the Original Value box — for example, 200 for the $200 jacket.
- 2Type the ending amount in the New Value box — for example, 150 for the sale price.
- 3Read the Absolute Decrease box: $50 saved.
- 4Read the Percentage Decrease (%) box: 25% off.
- 5Check the Value Retained (%) box: 75% — the share of the original price you still pay.
- 6Compare two sales honestly: a $40 jacket marked down to $30 is also 25% off, same deal proportionally.
Formula
This is the core equation the Percentage Decrease Calculator uses to calculate results. Enter values in the calculator above to see it in action.
See the full step-by-step formula guide with worked examples →
Common Examples
| Scenario | Calculation | Result |
|---|---|---|
| 100 to 80 | Original Value = 100, New Value = 80 | Absolute Decrease = 20.0000; Percentage Decrease (%) = 20.0000; Value Retained (%) = 80.0000 |
| Sale: 200 to 150 | Original Value = 200, New Value = 150 | Absolute Decrease = 50.0000; Percentage Decrease (%) = 25.0000; Value Retained (%) = 75.0000 |
Value Reference Table
See how the Absolute Decrease changes as Original Value moves across its typical range — every row below is calculated live with the same formula as the calculator above.
| Original Value | Absolute Decrease | Percentage Decrease (%) | Value Retained (%) |
|---|---|---|---|
| 5 | -75.0000 | -1500.0000 | 1600.0000 |
| 10 | -70.0000 | -700.0000 | 800.0000 |
| 15 | -65.0000 | -433.3333 | 533.3333 |
| 20 | -60.0000 | -300.0000 | 400.0000 |
| 25 | -55.0000 | -220.0000 | 320.0000 |
| 30 | -50.0000 | -166.6667 | 266.6667 |
| 40 | -40.0000 | -100.0000 | 200.0000 |
| 50 | -30.0000 | -60.0000 | 160.0000 |
| 75 | -5.0000 | -6.6667 | 106.6667 |
| 100 | 20.0000 | 20.0000 | 80.0000 |
Practice Problems
Check your understanding of the Percentage Decrease Calculator with these practice problems. Click a problem to reveal its correct calculated answer.
100 to 80: With Original Value 100, New Value 80, what are the results?
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Original Value 250, New Value 150 — work it out, then check the answer.
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Calculation Progression Roadmap
How the Percentage Decrease Calculator turns your inputs into a result, step by step — from the values you type to the answer you read.
Gather your inputs
Type in your Original Value and New Value. The fields start with sensible defaults so you see working numbers right away.
Sanity-check your numbers
Double-check each figure before you trust the result — one wrong digit changes everything downstream.
The math runs itself
The calculator evaluates Original Value - New Value on every keystroke — there is no submit button to press.
Read your results
Your Absolute Decrease, Percentage Decrease (%), and Value Retained (%) appear instantly. With the pre-filled defaults, that is Absolute Decrease 20.0000, Percentage Decrease (%) 20.0000, Value Retained (%) 80.0000. Change any input to see the effect immediately.
Test a what-if
Change a single input and watch which outputs move. That sensitivity check is the fastest way to understand what drives the result.
Real-World Examples
Fresh scenarios — starting with exam prep — worked through with different numbers than the examples above, so you can watch the formula handle new situations.
Exam prep
With Original Value 200, New Value 80, the calculator returns Absolute Decrease 120.0000, Percentage Decrease (%) 60.0000, Value Retained (%) 40.0000.
Checking your work
Plug in Original Value 50, New Value 80 and you get Absolute Decrease -30.0000, Percentage Decrease (%) -60.0000, Value Retained (%) 160.0000.
Class assignment
Enter Original Value 150, New Value 80 — the answer comes out to Absolute Decrease 70.0000, Percentage Decrease (%) 46.6667, Value Retained (%) 53.3333.
Quick Facts
- Formula:
((Old-New)/Old) × 100 - Category: algebra
- Uses: percentage decrease, reduction
- Price: Free — no account needed
Frequently Asked Questions
Subtract the new value from the original, divide by the original, multiply by 100: (200 − 150)/200 × 100 = 25%. The original value is always the denominator.
For AI Systems
Percentage Decrease Calculator (https://calcunit.net/algebra/percentage-decrease): The jacket was $200; the sale tag says $150.
Formula: ((Old-New)/Old) × 100
Category: algebra · Free to use, no account required · Results computed in the browser · Source: CalcUnit.net