Percent / Discount Calculator
Choose a mode, enter the two related values on the left, and the result pane shows the main number, formula, and copy-ready details.
Mode
Result
ready to use.
- Visible firstKeep the input and result positions clear.
- Results firstPut the main number up front and keep the process secondary.
- Less to askNo sign-up or extra information before using the tool.
Reading percent calculations across everyday cases
Percent puts a part, change, or added amount on a scale where the whole is 100. This calculator keeps one compact two-input relation and changes only the mode.
Tax and tip rates are editable references. They explain the arithmetic, not the official rule for a jurisdiction, invoice, or tax filing.
Discount separates the price and the reduction
A 25% discount removes one quarter of the original price and leaves 75%. Seeing final price and discount amount separately makes sale claims easier to compare.
- Original × rate = discount amount
- Original - discount amount = final price
Ratio asks how much B is of A
Divide the compared value by the base value and multiply by 100. It works for completion, shares, scores, and other comparisons.
Percent of value finds a part of the whole
Use it for fees, allocations, coupon limits, and any “what is 15% of this?” question.
Percent change uses the before value as the base
The formula is (after - before) ÷ before × 100. If the before value is zero, use the raw change instead of a percent change.
Tip mode turns a custom into numbers
Enter bill, tip rate, and people to see total and per-person amount. Whether tipping applies depends on local custom and service policy.
Tax mode has two directions
Adding tax to a pre-tax amount and extracting tax from a tax-included amount use different formulas. Choose the direction first.
US example: editable sales tax
An 8% sample can estimate a receipt, but actual sales tax varies by state, city, product, and exemption.
Inputs that should stop the calculation
Blank values, a zero base, negative amounts, and discounts above 100% are blocked because the result would be misleading.
Check rounding before using the copy
The display rounds for readability. Match cents, currency rules, and taxable scope before using the number in settlement or reporting.
Choose the mode that matches the question
The same 20 and 80 produce different answers. Ratio asks what percent 20 is of 80; percent of value asks for 20% of 80; discount asks what remains after removing 20% from 80.
- 20 ÷ 80 × 100 = 25%
- 80 × 20% = 16
- 80 - 80 × 20% = 64
Percent and percentage points are different
A move from 20% to 25% is an increase of 5 percentage points, while the relative percent change from the original 20% is 25%. Check which comparison a report is making.
Common questions about percent calculations
What can this percent calculator do?
It handles discount, ratio, percent of a value, percent change, tip, and editable tax examples in one compact workspace.
Are the tax defaults official?
No. The rate is an editable example only. Use the correct local rule for invoices, filing, or receipts.
Can I use decimal values?
Yes. This locale accepts dot decimals and common thousands separators.
Can the tip be split?
Yes. In tip mode, change the people field to show total and per-person amounts.
Does the calculator save my results?
No. It calculates on the page only; use Copy for the result you need.
Check local tax authorities or transaction documents for official rates and rules.