—
Work out a pay rise as a percentage or amount — free, no sign-up, nothing leaves your browser.
A percentage increase and the same percentage decrease aren't mirror images of each other, because each one is calculated on a different base figure. £30,000 plus 10% is £33,000 — but 10% off £33,000 is £3,300, not £3,000, leaving £29,700, not the original £30,000. This matters whenever pay moves in more than one step: a rise followed later by a cut back to "the same percentage" actually leaves you worse off than where you started, and the reverse is also true — a cut followed by the same percentage rise doesn't fully make up the loss either. The percentage always applies to whatever the current figure is at that moment, not the original one.
Yes — enter a negative percentage, or a new salary that's lower than the old one, and it works the same way in reverse.
No — these are gross (before tax) figures. A pay rise doesn't increase your take-home pay by the same percentage once tax and National Insurance are applied.
Switch to "Old + new salary → %" mode, enter your current salary as the old figure and your target as the new one, and it'll show you the exact percentage increase that gap represents.
No. Everything is calculated locally in your browser — nothing you enter is sent to a server.