Core percentage calculators
The everyday math the rest of the site is built around.
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Percentage of a number
What is X% of Y? Single-step calculation.
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What percent is X of Y
Reverse percentage: figure out what proportion one number is of another.
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Percentage change
From an old value to a new value — gain or loss, expressed as a percent.
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Reverse percentage (find original)
If X% of a number is Y, what was the original?
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Fraction ↔ decimal ↔ percent
Three-way live converter.
Shopping & consumer math
Tip splits, discounts, sales tax, multi-layered coupons.
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Tip calculator
Bill, tip percentage, number of people, share strings.
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Discount calculator
Original price, discount percent, money saved, final price.
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VAT calculator (generic)
Add or remove value-added tax at any rate.
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Country-specific VAT & sales tax
14 jurisdictions — UK, Germany, France, Italy, Spain, NL, Poland, Sweden, California, Texas, NY, Florida, Illinois, Washington.
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Stacked discount math
Layered "20% off plus extra 15%" calculator with the right multiplication.
Finance & investment
Loans, compound interest, returns, retirement.
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Compound interest
Principal, rate, time, compounding period. Final value plus interest breakdown.
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Loan / EMI
Monthly payment, total interest, amortization chart.
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Simple interest
I = P × r × t. The math behind short-term loans and basic deposit accounts.
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ROI (return on investment)
Profit divided by cost, expressed as a percent.
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Profit margin
Margin vs markup — the two are easy to confuse and produce different numbers.
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Inflation calculator
What is $100 from 1990 worth today? Historical CPI for US, UK and Eurozone.
Income & tax
Wage conversion, progressive tax brackets, country-specific tax math.
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Salary / hourly wage
Convert any wage to hourly, weekly, monthly or annual instantly. Custom work-week supported.
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Income tax brackets
Progressive tax calculator for US, UK, Germany, France and Canada. Marginal and effective rate.
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VAT / sales tax by country
14 jurisdictions — UK, Germany, France, Italy, Spain, NL, Poland, Sweden plus 6 US states.
Shopping discount pages with calculators
Product-specific landing pages — each has its own discount widget seeded with real 2026 prices.
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iPhone discount
iPhone 16, 16 Plus, 16 Pro and 16 Pro Max with trade-in math.
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TV discount
OLED, QLED, mini-LED with the holiday pricing calendar.
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Laptop discount
MacBook, Dell XPS, ThinkPad, gaming laptop pricing.
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Gaming console discount
PS5 Pro, Xbox Series X, Switch 2 with bundle math.
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Headphones & AirPods
AirPods Pro 2, Sony WH-1000XM6, Bose QC Ultra.
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Car purchase math
Dealer discount, trade-in, manufacturer rebate, financing.
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Kitchen appliances
Refrigerator, dishwasher, range, washer with the 4-weekend sale calendar.
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Fitness equipment
Peloton, NordicTrack, Hydrow with subscription math.
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Personal care
Dyson Airwrap, Braun, Oral-B, Theragun.
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Clothing & apparel
Levi's, Lululemon, Patagonia, Theory.
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Cosmetics & makeup
Sephora, Ulta, La Mer, Pat McGrath, perfume math.
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Subscription services
Streaming, software, memberships, the annual audit.
Utility & reference
Things that aren't single-formula calculators but live in the same toolbox.
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Bulk CSV percentage
Upload a CSV, apply a percent calc to every row, download.
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Percentage cheat sheet
Quick-reference card: common percentages, key formulas, mental-math shortcuts.
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Interactive lessons
15-lesson curriculum from basics to compound interest and ROI.
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Calculator history
Browser-local history of every calculation, exportable to CSV.