Free Online Calculators — 37 precision tools

Mortgage and loan schedules, BMI and calorie estimates, scientific math, prepress PDF point conversions, and SaaS metrics — instant, accurate, and completely offline.

All 37 tools

• PDF & Print DPI — Convert dimensions across Millimeters, Inches, Pixels, and PDF Points for prepress & web.
• Aspect Ratio & Scaler — Compute width/height keeping 16:9, 9:16, 4:3, 1:1, 21:9 with scaling multipliers & CSS code.
• Scientific Calculator — Calculator.net-grade 40-button scientific console with trig inverses, powers, roots, Ans, and memory.
• Percentage Calculator — Solve "X% of Y", "X is what % of Y", and percentage increase/decrease in one click.
• Universal Unit Converter — Instant two-way conversion for Length, Weight, Temperature, Speed, and Surface Area.
• Date & Business Work Days — Calculate exact elapsed duration, business working days (excluding weekends), and future date offsets.
• SaaS Unit Economics — MRR ⇄ ARR converter, LTV:CAC health ratio benchmarking, payback periods, and revenue churn rate.
• Profit Margin & Break-Even — Calculate Cost of Goods (COGS), Selling Price, Gross Profit, Markup %, and Break-Even units.
• VAT, Sales Tax & Discount — Forward tax addition and reverse VAT extraction with stacked multi-tier coupon discounts.
• BMI & Calorie Fitness — Body Mass Index gauge, healthy weight range, and Mifflin-St Jeor daily maintenance/weight-loss calories.
• Programmer & Bitwise — Simultaneous HEX, DEC, OCT, and BIN converter with bitwise logic, shifts, and interactive bit grid.
• Retirement Calculator — Project your retirement nest egg from current savings, contributions, and employer match — with safe withdrawal income.
• Inflation Calculator — See how inflation erodes purchasing power over time and project the future cost of goods and services.
• Income Tax Calculator — Estimate US federal income tax across progressive brackets, plus FICA, with effective and marginal rates.
• Salary Calculator — Convert between hourly wage and salary across all pay frequencies — hourly, weekly, biweekly, semi-monthly, monthly, annual.
• Payment Calculator — Find the fixed monthly payment for a loan, or how long a fixed payment takes to pay a balance off.
• Finance / TVM Calculator — Time-value-of-money workbench: present value, future value, and ordinary annuity payments in one console.
• Body Fat Calculator — Estimate body fat percentage with the US Navy circumference method, plus lean mass and category classification.
• Ideal Weight Calculator — Compare four classic ideal-body-weight formulas (Devine, Robinson, Miller, Hamwi) plus the healthy BMI weight range.
• Pace Calculator — Calculate running pace per km/mile, speed, and projected finish times for classic race distances.
• Pregnancy Calculator — Full pregnancy timeline: due date, conception, gestational age today, weeks pregnant, and trimester progress.
• Pregnancy Conception Calculator — Estimate when conception occurred — and the fertile window — from an LMP, due date, or ultrasound date.
• Due Date Calculator — Estimate your baby’s due date with Naegele’s rule from LMP, conception, or ultrasound — plus trimester and viability milestones. Free.
• Fraction Calculator — Add, subtract, multiply and divide fractions with automatic simplification, mixed numbers, and decimal conversion.
• Random Number Generator — Generate random integers in any range — unique or with repeats — plus dice, coin flip, lottery, and list shuffler shortcuts.
• Triangle Calculator — Solve any triangle: sides, angles, area, and perimeter from SSS, SAS, or ASA input using the law of sines and cosines.
• Standard Deviation Calculator — Compute population & sample standard deviation, variance, mean, median, mode, quartiles, outlier fences, and z-score percentiles.
• Age Calculator — Exact age in years, months, and days — plus a countdown to your next birthday and totals in days, hours, minutes, and seconds.
• Time Calculator — Clock math (add/subtract time) plus a duration arithmetic mode that breaks H:M:S down into every unit.
• Hours Calculator — Timesheet-style weekly hours: clock in/out per day with breaks, overtime, and gross pay at your rate.
• GPA Calculator — Weighted GPA on the 4.0 scale from course credits and letter grades, with plus/minus precision.
• Grade Calculator — Compute your current weighted course grade and find what you need on the final to hit your target.
• Concrete Calculator — Estimate concrete volume for slabs, footings, and columns — in cubic yards/meters — plus cement bags and cost.
• Subnet Calculator — IPv4 CIDR subnetting: network address, broadcast, usable host range, wildcard mask, and host capacity.
• Password Generator — Cryptographically random passwords with length and character-set control, entropy scoring, and passphrase mode.
• Storage & Transfer Time — Binary/Decimal storage conversions and upload/download transfer duration estimator.
• Asset & Unit Intelligence Hub — Live currency, crypto and industrial unit conversions with audit trail, trend chart and CSV reporting.