Calculators
Everyday math for shopping, loans, and planning—labeled with common U.S. terms (sales tax, APR, monthly payment). All listed tools run locally in your tab unless a page states otherwise.
Sales tax
ClientPrice before tax plus a combined state/local rate—tax amount and total, in your browser.
Percentage
ClientPercent of a number, what percent one value is of another, and percent change—client-side.
Age
ClientAge from a birth date to today or a chosen date—years, months, and days.
Discount
ClientOriginal price and discount percent—amount saved and sale price, locally.
Tip
ClientSubtotal, tip %, optional sales tax on the check, and per-person totals—split the bill.
Loan payment
ClientPrincipal, APR, and term—estimated monthly payment and total interest (amortizing loan).
Compound interest
ClientLump sum, APR, years, and compounding—future value, interest earned, and APY in your browser.
Profit margin
ClientRevenue and cost—gross profit, margin on revenue, and markup on cost.
Date difference
ClientDays between two calendar dates—useful with timestamps and planning.
Unit converter
ClientLength, temperature, and weight—metric and US customary; paste one value, see all units in the column.
Speed converter
Clientkm/h, mph, knots, m/s, and ft/s with standard mile and nautical definitions—paste one value, see every column.
Volume converter
ClientmL, L, m³, US kitchen units, US liquid gallon, and UK gallon—paste one value, see every column.
Area converter
Clientmm² through km², square inches/feet/yards, acres, and hectares—paste one value, see every column.
Pressure converter
ClientPa through MPa, bar, mbar, atm, psi, mmHg/torr, and inHg—paste one value, see every column.
Roman numerals
ClientArabic integers 1–3999 ↔ classical Roman letters (IV IX XL XC CD CM)—canonical spelling only, locally.
Nearby workflows on Toolcore
- Sales tax calculator — when you need subtotal plus state/local rate on a receipt.
- Loan payment calculator — for principal, APR, and term before comparing offers.
- Tip calculator — to split a bill after tax is already known.
- Unit converter — when the same shopping list mixes metric and US customary units.
Common use cases
- Use sales tax, discount, and tip tools when you want a quick checkout or dining estimate without a spreadsheet.
- Open loan or compound-interest pages when comparing APR quotes and monthly payment goals.
- Jump to length units when you already know the calculator hub and need a single conversion page.
- Convert outline years or trivia Roman strings with the Roman numerals card when you want Arabic integers without guessing spelling.
Common mistakes to avoid
Treating hub results as tax or legal advice
Outputs follow the formulas on each page. Rates, rounding rules, and regulations vary by jurisdiction—always verify with your own sources.
FAQ
Are my numbers uploaded?
No. Listed calculators run in your browser unless a specific page states otherwise.
Popular searches in this area
Phrases people search for that match this tool. See the full long-tail keyword index.
- length unit converter
- celsius to fahrenheit converter
- weight unit converter
- metric to imperial converter
More tools
Explore other utilities on Toolcore—useful next steps outside this hub.
JSON formatter
ClientJSON format online: pretty-print, minify, validate, escape, download .json.
Unix timestamp converter
ClientEpoch to date: seconds, milliseconds, ISO-8601, UTC and local time—in browser.
Tip calculator
ClientCheck subtotal, tip percent, optional sales tax on food, and split—common U.S. restaurant math.
Unit converter (length, temperature, weight)
ClientLength (metric & US customary), temperature (°C, °F, K), and weight (mg to lb)—paste one value, see every column.