Aureus Percentage Atelier
The sovereign standard for percentage computation — shares, proportions and changes, each with its formula shown.
Every figure is computed locally in your browser — nothing is sent to a server. This is a preview build, shared for design review.
How It Works — Three Simple Steps
No sign-up, no fuss — pick a mode, type your numbers, and read the answer with its working shown.
Pick Your Calculation
Choose one of three modes: find X% of a number, find what percent one number is of another, or measure the percentage increase or decrease between two values.
Type Your Numbers
Enter the two values the mode asks for — decimals and large numbers are welcome. In the first mode you can tap a preset chip (5%, 10%, 15%…) instead of typing the rate.
Read the Answer & Formula
The ivory result card shows the answer in large type, the exact formula that produced it, and handy extras like the remainder — so you can check the working, not just trust it.
Frequently Asked Questions
The principles behind shares, proportions and percentage change.
Divide the part by the whole and multiply by one hundred:
Example: 375 out of 2,500 → (375 ÷ 2,500) × 100 = 15%. That is Mode 2 of the calculator above.
Percentage change compares the difference between two values with the starting value:
A positive result is an increase (200 → 250 is +25%); a negative result is a decrease (250 → 200 is −20%). That is Mode 3 above.
Yes. Decimal values like 12.5% and negative values (for discounts or drops) are supported in every mode. Results are shown to up to four decimal places, with trailing zeros trimmed.
No. All calculations run entirely in your own browser — the numbers you type never leave your device, and nothing is stored or tracked.
A percentage point is the plain difference between two percentages — going from 10% to 12% is +2 percentage points. The percent change is relative: (12 − 10) ÷ 10 = +20%. Mode 3 calculates the relative percent change.
Aureus Precision Guarantee
Every answer ships with its formula, so the working can always be checked by hand.