Percentage Calculator
Turn discount tags, tip requests, and growth rates into clear numbers without memorizing formulas.
Percentage questions sound simple until you mix “what is 18% of,” “what percent is A of B,” and “increase by 12%.” This calculator separates those patterns so you pick the question type instead of rearranging algebra by hand.
Retail discounts, sales tax, grade weights, and month-over-month KPIs all reuse the same ratio math. Entering base and rate once reduces the off-by-one mistakes that happen when people multiply by 0.18 in their heads under time pressure.
Finance-heavy loan amortization belongs on the loan calculator; unit swaps belong on the unit converter. Stay here when the core ask is a percentage relationship between two amounts.
How to use
- Pick the question type — Choose whether you need a percentage of a number, a reverse percentage, or a change between two values.
- Enter the base amount — Type the original price, score total, or starting metric exactly as written on the receipt or report.
- Enter the rate or second value — Add the percent, or the comparison amount if you are computing change.
- Read the result — Check absolute difference and percentage together when both are shown—context matters for discounts versus growth.
- Apply the answer — Copy the figure into your cart, spreadsheet, or note. Recalculate if tax is stacked on top of a discount.
Use cases
- Sale pricing — Compute final price after a stated discount before you check out online or in-store.
- Tips and service charges — Convert a tip percentage into a dollar (or local currency) amount on a bill total.
- Performance deltas — Express week-over-week or year-over-year change as a clean percentage for meetings.
Tips
- Decide whether tax is included before you apply a discount—order of operations changes the total.
- “Increase by 20%” is not the same as “increase to 20%”; read the wording twice.
- For currency totals after FX conversion, convert first, then apply the percentage.
- Grades weighted by category often need several percentage steps—calculate each weight separately.
FAQ
Typical cases include X% of Y, Y is what percent of X, and percent increase or decrease between two numbers.
No. It performs arithmetic only. Investment or loan decisions need separate advice and full amortization tools.
No. Enter numbers only—this calculator works entirely from typed values.
Merchants may round differently, add tax after discounts, or exclude shipping. Match their checkout order of operations.
Use the loan calculator for installment math. This page is for simple percentage relationships.
Pair with the basic calculator, loan calculator, or currency converter depending on the next step.