Number Calculators · 219 microapps
219 calculators.
None of them want your email.
BMI, mortgage, percentage, p-value, sales tax, factorial — every calculator you'd Google. They open in a second, do one thing, and never make you "sign up to see the answer." Pick one below.
Most popular
The 12 calculators people open every day
Percentage Calculator
Calculate percentages, discounts & more
Tip Calculator
Calculate tips and split bills
BMI Calculator
Calculate your Body Mass Index
Loan Calculator
Calculate monthly payments & total interest
Mortgage Calculator
Monthly payment, PITI breakdown, total interest, payoff date
Discount Calculator
Calculate sale prices and savings
Compound Interest Calc
See how your money grows over time
Average Calculator
Calculate mean, median, mode & range
Sales Tax Calculator
Add tax to a price or extract tax from a total — US state presets included
GPA Calculator
Calculate your Grade Point Average
Standard Deviation Calculator
Sample and population SD plus mean, median, variance, min/max — paste any list of numbers
Salary to Hourly
Convert annual salary to hourly rate
Money & finance
Mortgages, taxes, retirement, debt — the calculators that move money.
Mortgage Calculator
Monthly payment, PITI breakdown, total interest, payoff date
Loan Calculator
Calculate monthly payments & total interest
Tip Calculator
Calculate tips and split bills
Car Loan Calculator
Monthly payment, total interest, total cost — for any auto loan
Credit Card Payoff Calculator
Months until debt-free + total interest at any monthly payment
Debt Snowball Calculator
Snowball + avalanche side-by-side: months to debt-free + total interest
House Affordability Calculator
Max home price you can afford using the 28/36 DTI rule
Compound Interest Calc
See how your money grows over time
Tax Bracket Calculator
US federal income tax — marginal rate, effective rate, per-bracket breakdown
Sales Tax Calculator
Add tax to a price or extract tax from a total — US state presets included
Discount Calculator
Calculate sale prices and savings
Emergency Fund Calculator
How much to save for an emergency fund — 3, 6, 9, 12 month tiers
Savings Goal Calculator
Required monthly contribution to hit a savings target by a specific date
Net Worth Calculator
Total assets minus liabilities — what you're worth
Inflation Calculator
What was $X in year Y worth today? US CPI-U, 1913–2025
401(k) Calculator
Project retirement balance with employer match + investment growth
Roth IRA Calculator
Project your tax-free retirement balance
HSA Contribution Calculator
2025 HSA limits, tax savings, and 30-year invested projection
Millionaire Calculator
How long until you hit $1M (or any target) given starting balance, monthly contributions, and rate of return
ROI Calculator
Total ROI + annualized return (CAGR) — compare investments fairly
50/30/20 Budget Planner
Senator Warren's classic — needs / wants / savings split
Break-Even Calculator
Units (and revenue) needed to cover all costs
Freelance Rate Calculator
Hourly rate that actually covers tax, expenses, non-billable time
Life Insurance Needs Calculator
How much term life insurance you actually need (DIME method)
Business Insurance Cost Estimator
Annual cost ranges for GL, Professional Liability, and BOP
Annual Income Calculator
Convert any pay rate (hourly, weekly, monthly) to annual — and back to every other interval
Salary to Hourly
Convert annual salary to hourly rate
Math & statistics
Algebra, stats, formulas. The math you'd use after school.
Percentage Calculator
Calculate percentages, discounts & more
Percent Difference Calculator
Difference vs change — both formulas, in one tool
Average Calculator
Calculate mean, median, mode & range
Standard Deviation Calculator
Sample and population SD plus mean, median, variance, min/max — paste any list of numbers
Geometric Mean Calculator
Calculate geometric mean of a dataset
P-value Calculator
Z-score → p-value with significance verdict
Factorial Calculator
Compute n! exactly for n up to 170, scientific notation up to n = 1000
Combination Calculator
C(n, k) = n! / (k! × (n−k)!) — selections where order does not matter
Permutation Calculator
P(n, k) = n! / (n−k)! — arrangements where order matters
Logarithm Calculator
ln (natural), log₁₀, log₂, or any custom base — answers 'what power gives me this number?'
Long Division Calculator
Divide step-by-step with the algorithm you learned in school — quotient, remainder, and every intermediate step
Quadratic Formula Calculator
Solve ax² + bx + c = 0 with steps and discriminant
Prime Number Checker
Check if a number is prime instantly
Fraction Calculator
Add, subtract, multiply, divide fractions — auto-simplified
Fraction Simplifier
Simplify fractions to their lowest terms
Square Root Calculator
Calculate square roots and nth roots
Scientific Notation Converter
Convert numbers to/from scientific notation
Random Number Generator
Generate random numbers within any range
Histogram Maker
Create a histogram from data values
Distance Formula Calculator
Calculate distance between two points in 2D or 3D space
GPA Calculator
Calculate your Grade Point Average
Final Grade Calculator
Course grade, final exam needed, and letter scale — all in one
Geometry & shapes
Area, volume, surface, slope — the shapes you remember from school.
Rectangle Area Calculator
Area, perimeter, and diagonal from length and width
Area of a Triangle Calculator
Three methods: base × height, Heron's, or two sides + angle
Circumference of a Circle Calculator
Calculate circumference, area, and diameter from radius (or radius from diameter)
Diameter of a Circle
Find diameter from radius, circumference, or area
Pythagorean Theorem Calculator
Find the hypotenuse or any leg of a right triangle (a² + b² = c²)
Volume Calculator
Volume of cube, rectangular box, cylinder, sphere, cone, or pyramid — one tool
Volume of a Cube Calculator
Volume from one side length — plus surface area, face & space diagonals
Volume of a Cylinder Calculator
Find cylinder volume, surface area, and lateral area from radius and height
Volume of a Sphere Calculator
Sphere volume from radius or diameter — plus surface area and great-circle circumference
Volume of a Cone Calculator
Cone volume from radius and height — plus slant height and surface area
Volume of a Triangular Prism
V = ½ × base × height × length, with surface area
Surface Area Calculator
Surface area of cube, box, cylinder, sphere, cone, or pyramid — total and lateral
Slope Calculator
Find the slope between two points — plus equation, angle, distance, and midpoint
Degrees to Radians Converter
Convert angles between degrees and radians (with π form)
Square Footage Calculator
Add up rooms in ft, in, m, or cm — totals shown in sq ft and m²
Health & fitness
BMI, calories, macros, hormones. Body math.
BMI Calculator
Calculate your Body Mass Index
Calorie Calculator
Estimate daily calorie needs
TDEE Calculator
Total Daily Energy Expenditure with cut/maintain/bulk calorie targets
Macro Calculator
Daily protein, carbs, fat targets by goal and macro preset
Water Intake Calculator
Daily water needs by weight, activity, climate, and life stage
One Rep Max Calculator
Estimate 1RM from any set (Epley, Brzycki, Lander) + intensity chart
Army Body Fat Calculator
Calculate body fat using the Army method
Height Predictor
Predict a child's adult height from parental heights using the mid-parental (Tanner) method
Period Calculator
Predict your next 4 periods plus ovulation and fertile window from your last period date and cycle length
Ovulation Calculator
Find your ovulation date, fertile window, and peak conception days for the next 3 cycles
Due Date Calculator
Pregnancy due date from last period, conception, or IVF transfer — plus current week and trimester
Dog Age Calculator
Convert dog years to human years using the modern AVMA formula — size-adjusted, not the '× 7' myth
Unit converters
Imperial to metric, kitchen to lab, here to there.
Unit Converter
Convert between any units of measurement
Length Converter
Convert meters, feet, inches, miles
Weight Converter
Convert kg, lbs, oz, stone, grams
Temperature Converter
Convert Celsius, Fahrenheit, Kelvin
Mass Calculator
Convert mass and weight units
Feet to Cm Converter
Convert feet (with inches) to centimeters and back
Feet to Inches Converter
Convert feet to inches (and back) with common reference table
Inches to Feet Converter
Convert inches to feet (and back) with common reference table
mm to Inches Converter
Convert millimetres to inches (and back) — for screen sizes, jewelry, drill bits
Grams to Ounces Converter
Convert grams to ounces (and back) with cooking & kitchen reference
Grams to Moles Converter
Convert grams to moles (and back) with a built-in compound picker
Oz to Cups Converter
Convert fluid ounces to cups (US, UK, metric)
Ounces to Pounds Converter
Convert oz to lb (and back) with kitchen & shipping reference
mL to fl oz Converter
Convert millilitres to US fluid ounces, with cooking measurements
Mg to Ml Converter
Convert milligrams to millilitres (and back) — for water, oils, alcohol, and medications
Tablespoon to Grams Converter
Convert tbsp to grams (and back) for flour, sugar, butter, salt, honey, oil, and 15+ kitchen staples
Nm to Ft-lbs Converter
Convert newton-meters to foot-pounds (and back) with torque references
Speed Distance Time Calculator
Calculate speed, distance, or time
Binary to Decimal
Convert binary to decimal and back
Roman Numeral Converter
Convert numbers to Roman numerals
Number to Words
Convert numbers into written word form
Around the house
Building, landscaping, fueling — the math of a Saturday project.
Concrete Calculator
Concrete needed for slabs, footings, columns, and stairs — in cubic yards, cubic metres, and bag count
Gravel Calculator
Volume + weight (tons) for a path, driveway, or landscaping
Mulch Calculator
How many bags or yards of mulch you need (with bag count)
Fuel Cost Calculator
Estimate fuel costs for any trip
Why we built 219
Calculator software is the most over-built category on the internet.
You've seen it. You Google "loan calculator," click the first result, and it's a 4 MB page with a cookie banner, a newsletter pop-up, three banner ads, a "Pro version" upsell, and somewhere underneath all that — eventually — a calculator. By the time the page renders, you've forgotten why you came.
Calculator.net is the gold standard of this. They have every calculator. They also have every dark pattern. We don't beat them on the math — the math is identical. We beat them on what we left out.
219 microapps. One job each. Each calculator is a single page that loads in under a second, does the calculation, and gets out of the way. No newsletter modal. No "Pro" tier. No pop-up at the eight-second mark begging for your email. The math is the same. The page respects you.
Speed
Loads in under a second
No client-side framework warming up. No third-party scripts. The calculator is on screen before competing pages finish loading their cookie banner.
Privacy
Your numbers stay yours
Every calculation runs in your browser. Your salary, weight, debt — none of it leaves your machine. Sign-up is optional and only saves favorites.
Honest
No "Pro" upsell
There is no Pro tier. Members get clean pages and AI tools at near-cost. The calculators are free for everyone — that's a fact, not a slogan.
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