Calculators that actually help.
SFCALTOOL is a fast, clean collection of free online calculators built for real-life questions — from money and math to health, dates, conversions and digital tasks.
Find the right calculator
Choose a category, then pick the exact tool you need.
Math & Numbers
Fast, clear calculators for percentages, fractions, ratios, averages and everyday math.
Finance & Money
Estimate loans, savings, interest, tips, taxes and practical money decisions.
Health & Fitness
Simple wellness calculators for BMI, calories, body measurements and fitness planning.
Time & Date
Work with dates, ages, time zones, durations, deadlines and calendar calculations.
Unit Converters
Convert length, weight, temperature, speed, area, volume, data and more.
Everyday Calculators
Useful calculators for discounts, cooking, fuel, electricity, shopping and daily life.
Tech & Digital
Practical tools for data, storage, bandwidth, pixels, aspect ratios and developer tasks.
Calculators by category
Every calculator has its own page and a detailed guide.
Math & Numbers
Fast, clear calculators for percentages, fractions, ratios, averages and everyday math.
Percentage Calculator
Calculate percentages, percentage increase and decrease, and find what percent one number is of another.
Instant browser result.
Clear inputs and useful output.
Helpful for quick checks and planning.
Fraction Calculator
Add, subtract, multiply and divide fractions with simplified results.
Instant browser result.
Clear inputs and useful output.
Helpful for quick checks and planning.
Average Calculator
Find the mean, median and range of a list of numbers in seconds.
Instant browser result.
Clear inputs and useful output.
Helpful for quick checks and planning.
Ratio Calculator
Solve ratios, simplify them, and find a missing value from a proportional relationship.
Instant browser result.
Clear inputs and useful output.
Helpful for quick checks and planning.
Proportion Calculator
Solve proportions and cross-multiplication problems quickly with a clear step-by-step result.
Instant browser result.
Clear inputs and useful output.
Helpful for quick checks and planning.
Exponent Calculator
Calculate powers, roots and exponential values for common math problems.
Instant browser result.
Clear inputs and useful output.
Helpful for quick checks and planning.
Square Root Calculator
Calculate square roots and verify perfect-square results instantly.
Instant browser result.
Clear inputs and useful output.
Helpful for quick checks and planning.
GCF LCM Calculator
Find the greatest common factor and least common multiple of two whole numbers.
Instant browser result.
Clear inputs and useful output.
Helpful for quick checks and planning.
Random Number Generator
Generate one or many random integers inside a range for games, testing and everyday choices.
Instant browser result.
Clear inputs and useful output.
Helpful for quick checks and planning.
Scientific Calculator
A browser-based scientific calculator for arithmetic, powers, roots, trigonometry and logarithms.
Instant browser result.
Clear inputs and useful output.
Helpful for quick checks and planning.
Fraction To Decimal Calculator
Convert a fraction to decimal form and simplify the fraction first.
Instant browser result.
Clear inputs and useful output.
Helpful for quick checks and planning.
Decimal To Fraction Calculator
Convert a decimal into a simplified fraction.
Instant browser result.
Clear inputs and useful output.
Helpful for quick checks and planning.
Cube Calculator
Calculate the volume and surface area of a cube from its side length.
Instant browser result.
Clear inputs and useful output.
Helpful for quick checks and planning.
Cylinder Volume Calculator
Calculate cylinder volume and surface area from radius and height.
Instant browser result.
Clear inputs and useful output.
Helpful for quick checks and planning.
Finance & Money
Estimate loans, savings, interest, tips, taxes and practical money decisions.
Loan Calculator
Estimate monthly payment, total interest and total repayment for a fixed-rate loan.
Instant browser result.
Clear inputs and useful output.
Helpful for quick checks and planning.
Mortgage Calculator
Estimate mortgage payments from home price, down payment, interest rate and loan term.
Instant browser result.
Clear inputs and useful output.
Helpful for quick checks and planning.
Compound Interest Calculator
See how savings can grow with compound interest, recurring contributions and time.
Instant browser result.
Clear inputs and useful output.
Helpful for quick checks and planning.
Simple Interest Calculator
Calculate simple interest and the final amount for a principal, rate and time period.
Instant browser result.
Clear inputs and useful output.
Helpful for quick checks and planning.
Savings Calculator
Estimate future savings from an initial balance, monthly deposits and interest rate.
Instant browser result.
Clear inputs and useful output.
Helpful for quick checks and planning.
Tip Calculator
Split a restaurant bill, calculate a tip percentage and see the amount per person.
Instant browser result.
Clear inputs and useful output.
Helpful for quick checks and planning.
Discount Calculator
Find the sale price, savings and final cost after a discount.
Instant browser result.
Clear inputs and useful output.
Helpful for quick checks and planning.
Sales Tax Calculator
Calculate tax amount and final price from a purchase total and tax rate.
Instant browser result.
Clear inputs and useful output.
Helpful for quick checks and planning.
Profit Margin Calculator
Calculate gross profit and profit margin from revenue and costs.
Instant browser result.
Clear inputs and useful output.
Helpful for quick checks and planning.
ROI Calculator
Measure return on investment as a percentage and calculate net gain from cost and return.
Instant browser result.
Clear inputs and useful output.
Helpful for quick checks and planning.
Health & Fitness
Simple wellness calculators for BMI, calories, body measurements and fitness planning.
BMI Calculator
Calculate body mass index from height and weight and view a standard adult BMI category.
Instant browser result.
Clear inputs and useful output.
Helpful for quick checks and planning.
Calorie Calculator
Estimate daily calorie needs using age, sex, height, weight and activity level.
Instant browser result.
Clear inputs and useful output.
Helpful for quick checks and planning.
Body Fat Calculator
Estimate body fat percentage with a simple circumference-based method for adults.
Instant browser result.
Clear inputs and useful output.
Helpful for quick checks and planning.
BMR Calculator
Estimate basal metabolic rate, the approximate energy your body uses at rest.
Instant browser result.
Clear inputs and useful output.
Helpful for quick checks and planning.
Ideal Weight Calculator
Compare several common height-based ideal-weight formulas for adults.
Instant browser result.
Clear inputs and useful output.
Helpful for quick checks and planning.
Pace Calculator
Calculate running pace, speed or finish time from distance and duration.
Instant browser result.
Clear inputs and useful output.
Helpful for quick checks and planning.
One Rep Max Calculator
Estimate your one-repetition maximum from a submaximal lift and reps performed.
Instant browser result.
Clear inputs and useful output.
Helpful for quick checks and planning.
Water Intake Calculator
Get a general daily water-intake estimate based on body weight and activity.
Instant browser result.
Clear inputs and useful output.
Helpful for quick checks and planning.
Time & Date
Work with dates, ages, time zones, durations, deadlines and calendar calculations.
Age Calculator
Calculate exact age in years, months and days from a birth date to any date.
Instant browser result.
Clear inputs and useful output.
Helpful for quick checks and planning.
Date Difference Calculator
Find the exact difference between two dates in days, weeks, months and years.
Instant browser result.
Clear inputs and useful output.
Helpful for quick checks and planning.
Time Calculator
Add or subtract hours, minutes and seconds without doing the math by hand.
Instant browser result.
Clear inputs and useful output.
Helpful for quick checks and planning.
Countdown Calculator
See how much time remains until a chosen date and time.
Instant browser result.
Clear inputs and useful output.
Helpful for quick checks and planning.
Business Days Calculator
Count weekdays between two dates, excluding weekends.
Instant browser result.
Clear inputs and useful output.
Helpful for quick checks and planning.
Weeks Between Dates Calculator
Calculate how many complete and fractional weeks separate two dates.
Instant browser result.
Clear inputs and useful output.
Helpful for quick checks and planning.
Time Zone Converter
Convert a date and time between common global time zones in your browser.
Instant browser result.
Clear inputs and useful output.
Helpful for quick checks and planning.
Unix Timestamp Converter
Convert Unix timestamps to readable dates and convert dates back to Unix time.
Instant browser result.
Clear inputs and useful output.
Helpful for quick checks and planning.
Date To Days Calculator
Convert a date to its day-of-year number and count remaining days in the year.
Instant browser result.
Clear inputs and useful output.
Helpful for quick checks and planning.
Hours To Minutes Calculator
Convert hours and fractional hours into minutes and seconds.
Instant browser result.
Clear inputs and useful output.
Helpful for quick checks and planning.
Minutes To Hours Calculator
Convert minutes into hours and remaining minutes for quick time planning.
Instant browser result.
Clear inputs and useful output.
Helpful for quick checks and planning.
Days Between Dates Calculator
Count the number of calendar days between two dates.
Instant browser result.
Clear inputs and useful output.
Helpful for quick checks and planning.
Unit Converters
Convert length, weight, temperature, speed, area, volume, data and more.
Length Converter
Convert common length units including mm, cm, m, km, inches, feet, yards and miles.
Instant browser result.
Clear inputs and useful output.
Helpful for quick checks and planning.
Weight Converter
Convert kilograms, grams, pounds, ounces, stones and tonnes instantly.
Instant browser result.
Clear inputs and useful output.
Helpful for quick checks and planning.
Temperature Converter
Convert Celsius, Fahrenheit and Kelvin with accurate formulas.
Instant browser result.
Clear inputs and useful output.
Helpful for quick checks and planning.
Area Converter
Convert square meters, square feet, acres, hectares and other area units.
Instant browser result.
Clear inputs and useful output.
Helpful for quick checks and planning.
Volume Converter
Convert liters, milliliters, gallons, cups, cubic meters and more.
Instant browser result.
Clear inputs and useful output.
Helpful for quick checks and planning.
Speed Converter
Convert km/h, mph, m/s and knots for travel, sports and engineering.
Instant browser result.
Clear inputs and useful output.
Helpful for quick checks and planning.
Data Storage Converter
Convert bytes, KB, MB, GB and TB using common binary or decimal units.
Instant browser result.
Clear inputs and useful output.
Helpful for quick checks and planning.
Energy Converter
Convert joules, calories, kilocalories, watt-hours and kilowatt-hours.
Instant browser result.
Clear inputs and useful output.
Helpful for quick checks and planning.
Everyday Calculators
Useful calculators for discounts, cooking, fuel, electricity, shopping and daily life.
Fuel Cost Calculator
Estimate trip fuel cost from distance, fuel economy and fuel price.
Instant browser result.
Clear inputs and useful output.
Helpful for quick checks and planning.
Electricity Cost Calculator
Estimate appliance electricity cost from power, usage time and electricity rate.
Instant browser result.
Clear inputs and useful output.
Helpful for quick checks and planning.
Cooking Converter
Convert common cooking measurements such as cups, tablespoons, teaspoons and milliliters.
Instant browser result.
Clear inputs and useful output.
Helpful for quick checks and planning.
Split Bill Calculator
Split a shared bill evenly and include an optional tip percentage.
Instant browser result.
Clear inputs and useful output.
Helpful for quick checks and planning.
Date Add Subtract Calculator
Add or subtract days, weeks or months from any date to find a future or past date.
Instant browser result.
Clear inputs and useful output.
Helpful for quick checks and planning.
Percentage Change Calculator
Calculate percentage increase or decrease between an original and a new value.
Instant browser result.
Clear inputs and useful output.
Helpful for quick checks and planning.
Break Even Calculator
Find the sales volume needed to cover fixed and variable costs.
Instant browser result.
Clear inputs and useful output.
Helpful for quick checks and planning.
Markup Calculator
Calculate selling price, markup amount and markup percentage from cost and target markup.
Instant browser result.
Clear inputs and useful output.
Helpful for quick checks and planning.
Unit Price Calculator
Compare products by cost per unit, weight or volume to find the better value.
Instant browser result.
Clear inputs and useful output.
Helpful for quick checks and planning.
Tech & Digital
Practical tools for data, storage, bandwidth, pixels, aspect ratios and developer tasks.
Password Generator
Generate strong random passwords with configurable length and character sets.
Instant browser result.
Clear inputs and useful output.
Helpful for quick checks and planning.
Data Transfer Time Calculator
Estimate download or upload time from file size and connection speed.
Instant browser result.
Clear inputs and useful output.
Helpful for quick checks and planning.
Image Aspect Ratio Calculator
Calculate image aspect ratio and missing width or height from known dimensions.
Instant browser result.
Clear inputs and useful output.
Helpful for quick checks and planning.
Pixels To Inches Calculator
Convert pixels to physical inches using a selected DPI value.
Instant browser result.
Clear inputs and useful output.
Helpful for quick checks and planning.
Hex To Decimal Calculator
Convert hexadecimal numbers to decimal and decimal values to hexadecimal.
Instant browser result.
Clear inputs and useful output.
Helpful for quick checks and planning.
Binary Calculator
Convert binary and decimal values and perform basic binary arithmetic.
Instant browser result.
Clear inputs and useful output.
Helpful for quick checks and planning.
Base64 Encoder Decoder
Encode text to Base64 or decode Base64 back into readable text in your browser.
Instant browser result.
Clear inputs and useful output.
Helpful for quick checks and planning.
Color Converter
Convert common HEX, RGB and HSL color formats for web and design work.
Instant browser result.
Clear inputs and useful output.
Helpful for quick checks and planning.
JSON Formatter
Format and validate JSON with readable indentation and clear error messages.
Instant browser result.
Clear inputs and useful output.
Helpful for quick checks and planning.
URL Slug Generator
Turn a title into a clean SEO-friendly URL slug using lowercase words and hyphens.
Instant browser result.
Clear inputs and useful output.
Helpful for quick checks and planning.
Word Character Counter
Count words, characters, sentences and reading time for any text.
Instant browser result.
Clear inputs and useful output.
Helpful for quick checks and planning.
Why SFCALTOOL?
Fast & lightweight
No heavy app required. Calculations run directly in your browser.
Clear results
We show useful context instead of dumping a number on the screen.
Helpful guides
Each major calculator is paired with an educational guide and FAQs.