YiJianSuan - 1435 Free Online Calculators across 10 Categories
1435 free calculators · ready to use, no sign-up, runs locally
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Basic Calculator
HOTScientific Calculator
HOTPercentage Calculator
Fraction Calculator
HOTNumber Base Converter
Permutation & Combination Calculator
Random Number Generator
Prime Number Tools
GCD & LCM Calculator
NEWSequence Calculator
NEWEquation Solver
NEWSquare Root Calculator
NEWCube Root Calculator
NEWAbsolute Value Calculator
NEWLogarithm Calculator
NEWExponent Calculator
NEWFactorial Calculator
NEWModulo Calculator
Statistics Calculator
View allMortgage Calculator
HOTAuto Loan Calculator
HOTIncome Tax Calculator
Freelance Income Tax Calculator
HOTTake-Home Pay Calculator
HOTCompound Interest Calculator
Inflation Calculator
ROI Calculator
Retirement Calculator
Loan Comparison Calculator
Early Mortgage Payoff Calculator
Savings Goal Calculator
Stock Return Calculator
Bond Price Calculator
Yield to Maturity Calculator
ETF Premium Calculator
Annuity Calculator
HOTCurrency Converter
Dividend Yield Calculator
View allBMI Calculator
Body Fat Calculator
Waist-to-Hip Ratio Calculator
BMR Calculator
TDEE Calculator
Ideal Weight Calculator
Pregnancy Due Date Calculator
Maternity Allowance Calculator
QTc Correction Calculator
Sodium to Salt Converter
Glycemic Load Calculator
Water Intake Calculator
Heart Rate Zone Calculator
Headphone Safety Calculator
NEWBody Surface Area Calculator
NEWPregnancy Weight Gain Calculator
NEWSleep Calculator
NEWDaily Calorie Calculator
NEWRunning Pace Calculator
View allLength Converter
Weight Converter
Area Converter
Volume Converter
Temperature Converter
Speed Converter
Time Unit Converter
Data Storage Converter
Pressure Converter
Power Converter
Angle Converter
Frequency Converter
Fuel Consumption Converter
Energy Converter
Ring Size Converter
Roman Numeral Converter
Screen PPI Calculator
Screen Size Calculator
Photo Print Size Calculator
View allAge Calculator
Date Difference Calculator
Date Calculator
Ebbinghaus Review Planner
Countdown Timer
Workday Calculator
Time Zone Converter
Weekday Calculator
Holiday Countdown
Chinese Lunar Calendar Converter
NEWSolar Terms Calendar
NEWChinese Zodiac Calculator
Week Number Calculator
Time Calculator
Zodiac Sign Calculator
Days Alive Calculator
Retirement Age Calculator
Annual Leave Calculator
Work Years Calculator
View allMedical Treatment Period Calculator
Medical Insurance Reimbursement Calculator
Tea Leaf Ratio Calculator
Carbon Footprint Calculator
Bill Splitter
Mobile Data Usage Calculator
Phone Plan Comparison
Discount Calculator
Tip Calculator
Fuel Cost Calculator
Size Converter
Color Converter
Password Generator
Password Entropy Calculator
Rent vs Buy Calculator
NEWGPA Calculator
Calorie Counter
Clothing Size Calculator
Final Grade Calculator
View allCPU Cooler Calculator
Tapping Drill Size Calculator
IPv6 Formatter
Guitar Capo Transposer
Base Converter for Developers
Color Code Converter
JSON Formatter
Base64 Encoder / Decoder
URL Encoder / Decoder
Unix Timestamp Converter
Regex Tester
Hash Calculator
Character Counter
Lorem Ipsum Generator
Markdown Preview
NEWText Diff Tool
NEWHTML Entities Converter
UUID Generator
QR Code Generator
View allPentagram Area Calculator
Circle Intersection Calculator
Circle Calculator
Triangle Calculator
Rectangle Calculator
Sphere Calculator
Trapezoid Calculator
NEWCone Calculator
NEWCylinder Calculator
NEWEllipse Calculator
NEWParallelogram Calculator
Regular Polygon Calculator
Pythagorean Theorem Calculator
Sector Calculator
Cuboid Calculator
Pyramid Calculator
Frustum Volume Calculator
Ellipsoid Volume Calculator
Annulus Calculator
View allVAT Calculator
Price Tax Separator
Invoice Amount Calculator
Profit Margin Calculator
Gross Margin Calculator
Depreciation Calculator
Break-Even Calculator
Markup Calculator
NEWCommission Calculator
Annualized ROI Calculator
Ad Performance Calculator
RMB Uppercase Converter
Employer Cost Calculator
Equity Dilution Calculator
CAC & LTV Calculator
Enterprise Income Tax Calculator
Inventory Turnover Calculator
E-commerce Profit Calculator
Container Loading Calculator
View allWall U-Value Calculator
Rocket Delta-V Calculator
Diving Gas Planner
Steel Weight Calculator
Ohm's Law Calculator
Electric Power Calculator
Resistor Series & Parallel Calculator
Engine Displacement Calculator
Renovation Cost Estimator
Tile Quantity Calculator
Wavelength Calculator
Force Calculator
NEWDensity Calculator
Speed of Sound Calculator
Paint Calculator
Flooring Calculator
Half-Life Calculator
Molar Mass Calculator
Free Fall Calculator
View allHome Renovation Calculator Pack9
A 9-step calculation chain from purchase to move-in: affordability, deed tax, mortgage, housing fund, renovation budget, tile & paint quantities, renovation loan and prepayment.Baby & Parenting Calculator Pack7
Seven tools from maternity pay to education savings: benefits, vaccine schedule, growth standards, height prediction, fever dosing, car-seat grouping and compound growth.Year-End Bonus & Take-Home Pack7
Bonus tax critical points, income tax, take-home pay, pension tax relief and deposit compounding — make the most of your year-end money.Social Insurance & Housing Fund Pack8
Housing fund, medical reimbursement, flexible employment, unemployment benefits, injury compensation, maternity pay, delayed retirement and pension — a life-cycle map of social insurance.Car Ownership Cost Pack6
On-road price, insurance, service intervals, fuel, parking and rentals — the full lifecycle cost from delivery to daily driving.Travel Abroad Prep Pack6
Exchange rates, time zones, tipping, baggage, sizing and temperature — every numeric question solved in 10 minutes before departure.Home Buying Calculator Pack6
A 6-step chain from house hunting to loan approval: affordability, deed tax, commercial monthly payment, housing fund, plan comparison and prepayment.Loan & Debt Calculator Pack5
A 5-step chain: auto loan, plan comparison, prepayment, take-home pay — know the numbers before you borrow.Saving & Investing Calculator Pack7
A 7-step dashboard for long-termists: compound growth, deposits, SIP, stock returns, dividends, FIRE and retirement.Fitness Training Calculator Pack8
An 8-step chain from body assessment to training loads: BMI, body fat, BMR, TDEE, 1RM, pace, exercise burn and race prediction.Pregnancy & Baby Calculator Pack6
A 6-step chain from conception to feeding: ovulation, due date, pregnancy weight, milk intake and formula prep.Health Monitoring Calculator Pack7
Seven routine metrics — blood pressure, heart rate, BMI, waist-to-hip ratio, body fat, ideal weight and BSA — to decode your checkup report.Equal Payment vs Equal Principal: Which Saves More?
Equal payment (annuity) keeps monthly payments constant; equal principal costs less interest overall but starts higher. Real test on a $1M loan: $67k interest difference over 30 years. Formulas, comparison tables, rate sensitivity analysis and a decision tree inside.
Finance · Updated 2026-08-01
Housing Provident Fund Loans: Rates, Limits & How to Apply
HPF rates are ~0.6 percentage points below commercial loans (2.6% vs 3.3% for first homes). Max loan is typically 0.6–1.2M depending on city and account balance. Covers rate tables, limit formulas, the commercial-to-HPF conversion process and common pitfalls.
Real Estate · Updated 2026-08-01
Take-Home Pay: Social Insurance, Housing Fund & Income Tax
Gross ¥10,000/month takes home roughly ¥7,500–8,000 after social insurance (~10.5%), housing fund (5–12%) and income tax. Includes the full deduction formula, 2025 social insurance base caps, special additional deductions and year-end bonus tax strategy.
Finance · Updated 2026-08-01
Home Buying Costs: Down Payment, Taxes & Fees Checklist
Beyond the down payment: deed tax 1–3%, agency fees 1–2.7%, maintenance fund ~2%, plus appraisal and mortgage fees. A ¥3M first home typically needs ¥450k down + ¥80–120k in taxes and fees. Full cost tables and city policy differences inside.
Real Estate · Updated 2026-08-01
Resale Home Taxes: VAT, Income Tax & Deed Tax Explained
Selling a resale home: VAT 5.3% if under 2 years (exempt after 2 years in most cities), income tax 1% of price or 20% of gain (exempt if owned 5+ years and only home), deed tax 1–3% paid by buyer. Includes the "满二/满五唯一" exemption rules and real cost tables.
Real Estate · Updated 2026-08-01
BMI Standard Ranges: Formula, Tables & Limitations
BMI = weight(kg) ÷ height(m)². Chinese standard: 18.5–23.9 normal, 24–27.9 overweight, ≥28 obese. WHO uses 25/30 cutoffs. Includes full classification tables, examples at common heights, and why muscular people and the elderly should read BMI with caution.
Health · Updated 2025-06-07
Daily Calorie Needs: BMR, TDEE & Deficit Planning
Daily burn (TDEE) = BMR × activity factor (1.2–1.9). A 30-year-old office worker at 70kg burns ~2,000–2,200 kcal/day. Fat loss: eat 300–500 kcal below TDEE for ~0.5kg/week. Includes Mifflin-St Jeor formula, activity tables and plateau troubleshooting.
Health · Updated 2026-08-01
Ideal Weight: Standard Formulas & Healthy Ranges
Common formulas: Broca (height−105 for men, −110 for women), BMI-based range (18.5–23.9 × height²), and Devine. A 175cm man's ideal range is ~57–73kg. Why a range beats a single number, and how frame size and muscle mass shift your personal target.
Health · Updated 2026-08-01
About YiJianSuan
There are plenty of calculators online; few actually explain the math. YiJianSuan takes a different approach: every tool page lays out the process — formulas with sources, step-by-step derivations, and example numbers verified by code. 130 common unit-conversion pairs get dedicated answer pages for frequently-used values.
Standards are explicit: BMI shows WHO and Chinese cut-points side by side, income tax follows the official cumulative-withholding method, loans compute both annuity and principal-equal formulas — differing standards are contrasted, never blended.
Privacy needs no promise, only architecture: every calculation runs locally in your browser, and inputs never leave your device. Everything is free, no sign-up, no limits — the way a calculator site should be.
A calculator site, as it should be.