Percentage calculator
Calculate a percentage, percentage change or increase.
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Understanding your calculation
Percentage change is (new - original) / absolute original x 100. A zero original value has no defined percentage change. For percentage-of mode, enter the rate in the first field and the base in the second.
- Enter your own values and choose the applicable calculation options.
- Review the breakdown and assumptions; change one input to compare a scenario.
- Download the calculation CSV to retain your inputs and result for independent checking.
Limits and checks
Inputs are validated locally. Results are estimates using the stated model, without live market data, automatic tax classification or personalized financial advice.
Frequently asked questions
What assumptions does the percentage calculator use?
Percentage change is (new - original) / absolute original x 100. A zero original value has no defined percentage change. For percentage-of mode, enter the rate in the first field and the base in the second.
Is my content sent to a server?
No. Processing runs inside your browser. Optional editor recovery saves a draft on this device only. Read the privacy policy.
Will my original file be changed?
No. Downloaded results are separate copies. Open the finished output before sharing it or deleting an original.