Online Calculators Hub: Loans, Taxes & Unit Conversion

Working out a mortgage payment, checking payroll tax, converting shoe sizes for overseas shopping — numeric questions pop up more often than you'd think. This hub curates the highest-frequency calculations and conversions: the loans & taxes section covers mortgages, car financing, annual bonus tax, stamp duty and online-loan interest with itemized results the moment you enter amounts and rates, including side-by-side repayment comparisons. The unit section handles length, weight, temperature, area, volume, speed and time, plus shoe-size charts for cross-border shopping. Daily-life extras include profit-margin/ROI, a payslip generator, blood-type inheritance rules and holiday countdowns. Formulas are transparent and easy to follow, everything computes right in your browser, no personal data is collected — open and calculate.

Loans & Taxes

5 tools

Payment breakdowns, total interest and tax deductions — know the numbers before you sign.

Loan Calculator

Online loan calculator with equal installment and equal principal modes showing monthly payment, interest and totals for mortgage planning.

Car Loan Calculator

Car loan calculator: price, down payment, rate and term in, monthly payment and total cost out, with down payment breakdown.

Annual Bonus Tax Calculator

China annual bonus tax calculator — compute IIT on the one-time bonus preferential rate and compare against combined taxation.

Stamp Duty Calculator

Stamp duty calculator by contract value and rate tier for property deals and pre-signing estimates.

Wangshangdai Interest Calculator

Wangshangdai interest calculator converting daily rate to APR: principal and term in, total interest out.

Unit Conversion

8 tools

From kitchen baking to engineering drawings, common quantities convert instantly.

Length Unit Converter Online

Convert between 12 metric, imperial and Chinese units from nanometers to nautical miles instantly — great for engineering, trade quotes and study, fully local.

Weight Unit Converter Online

Convert across 9 units from milligrams to tons including ounces, pounds, carats and Chinese jin/liang with exact factors — great for jewelry pricing, logistics and baking, fully local.

Temperature Unit Converter Online

Affine conversion across Celsius, Fahrenheit, Kelvin and Rankine scales with built-in zero-error formulas — for lab work, cooking and travel, fully local.

Area Unit Converter Online

Convert across 9 area units from mm² to km² including hectares, acres and Chinese mu with exact factors — for real estate, farming plans and renovations, fully local.

Volume Unit Converter Online

Convert across 9 volume units: ml, L, m³, cubic inches/feet plus US gallons, quarts and pints — for recipes, fuel tanks and dosing, fully local.

Speed Unit Converter Online

Convert across 6 speed units: m/s, km/h, mph, knots, ft/s and Mach — for driving, aviation, sailing and pace running, fully local.

Time Unit Converter Online

Convert across 8 time units from nanoseconds to weeks — for programming timers, project scheduling and duration estimates, with exact factors, fully local.

Shoe Size Converter

Cross-reference CN, EU, US men's/women's, UK sizes and foot length in centimeters — enter any size to highlight the matching row, perfect for overseas shoe shopping, fully local.

Daily-life Utilities

4 tools

Small helpers for business math, payslips, blood-type inheritance and holiday countdowns.

Profit Margin & ROI Calculator

Profit margin & ROI calculator: cost/price/revenue in, gross/net margins and ROI out instantly.

Payslip Generator

Payslip generator producing standard tables from base salary, insurance and tax inputs, exportable for small-business HR.

Blood Type Inheritance Calculator

Predict possible child blood types from parents' ABO types based on classic Mendelian inheritance — handy for pregnancy education and family curiosity, fully local.

Holiday Countdown Timer

Holiday countdown with built-in festival dates, live days/hours/minutes remaining.

FAQ

My bank's numbers differ slightly from the calculator — is that normal?

Yes. Banks may apply rate discounts or day-count conventions that differ slightly; the calculator returns exact values under standard annuity/linear amortization models, which is reliable enough for comparing options.

Do these calculators need an internet connection?

Once the page has loaded, all calculations run locally and nothing is sent to any server; even if your connection drops the tools keep working, and none of your figures are stored.

Which units are supported beyond the common ones?

Beyond length, weight and temperature, coverage includes pressure, power, frequency, density, fuel consumption, color temperature and bandwidth; a dedicated base converter handles binary/octal/hex needs.

Wrap-up & further reading

That completes this collection of calculators. Whether you are comparing loan offers or converting units, treat the results as a first step and double-check key figures with official sources. To understand how equal-payment and equal-principal repayments really differ, read ourequal payment vs equal principal comparison; more everyday utilities live in theLife & calculation category — bookmark this page and come back often.