Price Drop Calculator
Measure the dollar and percentage change from an old price to a new price.
Useful for price watching, resale buy decisions, and checking whether a discount is meaningful.
How to use this calculator
Measure the dollar and percentage change from an old price to a new price. Use the inputs to adjust the assumptions and compare outcomes before you make a decision.
- Replace the default inputs with your real costs and rates.
- Compare profit, margin, fees, and break-even points before acting.
- Bookmark the page if you use this calculation often.
When to use it
Use it before you list, buy, ship, renew, quote, or accept an offer. A single fee, shipping cost, or rate change can turn a good decision into a bad one, or rescue a deal that looked too thin.
Frequently asked questions
Is this calculator exact?
It is an estimate based on the numbers you enter. Check current fees, taxes, carrier rules, and marketplace policies before making an important decision.
Does RotoCurve store my inputs?
No login is required. The calculator runs in your browser and is designed for quick planning math.
Why do the defaults differ from my account?
Fees and rates vary by platform, category, country, plan, carrier, and account status. Replace defaults with your real numbers when you have them.