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Disclaimer

Last updated: October 2026

PctZen does one thing — as a percentage calculator it answers percent-of, what-percent, and percent-change questions instantly, with a discount and tip mode. It picks the right rearrangement of the percentage relationship for the question you ask — part over whole, or the difference over the original — so the same tool covers a markup and a discount without the sign confusion. What follows concerns only that tool and the inputs involved in it.

Everything the tool works with — the numbers you enter — is handled locally. It is usually reached for things like checking a percentage change between two figures, and because nothing is transmitted a visitor can close the tab knowing no copy was made anywhere.

The nature of this site

Nothing on pctzen.com is professional advice. What PctZen produces is an estimate of a calculation rather than a measured fact, published for general information and education.

Quick answers, with a caveat

This is a convenience tool producing a quick answer. If the outcome matters — a measurement you will act on, a number you will submit — confirm the PctZen result by other means.

No guarantees

The assumption that matters most for PctZen is that your input matches the model. It picks the right rearrangement of the percentage relationship for the question you ask — part over whole, or the difference over the original — so the same tool covers a markup and a discount without the sign confusion. When it does not — or when rounding, unit handling or browser behavior intervenes — no warranty attaches to the Site, careful as we are with the method.

Links to third-party sites

External links are offered for reference only. We neither control nor vouch for outside content or its accuracy.

Adverts and sponsorship

Adverts fund the Site and cannot influence a result. An advertisement appearing here is not an endorsement of the advertiser or the product.

Checking before you act

Make sure any result suits your own situation before you act on it. If you think something is wrong, the contact page is the quickest way to let us know.