Percentage Decrease Calculator
Quick percentage drop calculator.
Calculate percentage decrease between two values. See drop, retained, and ratio. Enter original value and new value for an instant result.
What this tool does
This tool calculates the percentage decrease between an original value and a new lower value. Enter both values to see percentage decrease, absolute drop, and retained percentage.
Enter Values
Formula Used
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Disclaimer
Results are estimates for educational purposes only. They do not constitute financial advice. Consult a qualified professional before making financial decisions.
Percentage decrease shows how much a value has dropped relative to the original. Sales discount, price drops, depreciation tracking - all use percentage decrease. This calculator takes original and new values and returns the decrease percentage.
A 150 item on sale for 100 has a 33.33% decrease (or 50 off). A 25,000 car depreciating to 17,500 represents a 30% decrease. The tool also shows retained percentage - 100 from 150 retains 66.67% of original value.
Useful for anyone tracking losses or discounts. Check sale validity ('is this really 50% off?'), quantify depreciation, measure rate drops, or compare downward movements across metrics.
Run it with sensible defaults
Using original value of 150, new value of 100, the calculation works out to 33.33%. Nudge the inputs toward your own situation and the output recalculates instantly. The defaults are meant as a starting point, not a recommendation.
The levers in this calculation
The inputs — Original Value and New Value — do not pull with equal force. Not every input has equal weight. Flip one at a time toward extreme values to feel which ones move the needle most for your situation.
How the math works
Decrease = original - new. Percentage = (decrease / original) × 100. Retained = 100 - decrease %. The working is transparent — you can verify every step yourself in the formula section below. No black box, no opaque "proprietary model".
Why run the calculation
Utility bills creep. Small annual increases stack into meaningful differences over a decade. Running this once a year and switching providers when the gap widens is one of the easiest ways to keep household costs in check.
What this doesn't capture
Usage varies month-to-month; tariffs change; discounts come and go. The figure here is a clean baseline — your actual annual bill will fluctuate around it. Use the calculation to benchmark providers, not as a prediction of a specific bill.
£150 £ to £100 £ = 33.33%.
Inputs
This example uses typical values for illustration. Adjust the inputs above to match a specific situation and see how the result changes.
Sources & Methodology
Methodology
Decrease = original - new. Percentage = (decrease / original) × 100. Retained = 100 - decrease %.
References
Frequently Asked Questions
When to use this?
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