1000 Calculators, Updated April 2026
The calculator
you actually need.
1000+ free calculators for finance, health, math, construction, and more. Real formulas. Instant results. No signup.
The calculators people reach for first.
View all →Mortgage Payment Calculator
Calculate your monthly mortgage payment including principal and interest. See total cost over the life of your loan.
BMI Calculator
Calculate your Body Mass Index (BMI) from height and weight. See where you fall on the BMI scale.
Percentage Calculator
Calculate what percentage one number is of another, or find a percentage of any number.
Compound Interest Calculator
Calculate how your money grows with compound interest over time. See the power of regular contributions.
TDEE Calculator
Calculate your Total Daily Energy Expenditure, the total calories you burn each day including activity.
Tip Calculator
Calculate how much to tip at restaurants and split the bill between multiple people.
Calorie Intake Calculator
Calculate how many calories you should eat daily based on your goals, lose, maintain, or gain weight.
GPA Calculator
Calculate your Grade Point Average (GPA) from individual course grades.
Concrete Calculator
Calculate how many cubic yards of concrete you need for slabs, footings, columns, and walls.
Age Calculator
Calculate your exact age in years, months, and days from your date of birth.
Car Payment Calculator
Calculate your monthly car payment including price, down payment, trade-in, and loan terms.
Solar Panel Calculator
Estimate how much electricity a solar panel system generates and how much money it saves you.
LLM API Cost Calculator
Calculate the cost of using large language model APIs (GPT-4, Claude, Gemini) based on token usage.
One Rep Max Calculator
Estimate your one-rep max (1RM) for any exercise using the Epley formula.
FIRE Calculator
Calculate your path to Financial Independence, Retire Early (FIRE) based on savings rate and expenses.
Browse by category.
All categories →Finance Calculators
178 calculators
Free financial calculators for mortgages, loans, investments, retirement planning, taxes, and more. Every calculator uses standard financial formulas, amortization, compound interest, time value of money, so you can plan with confidence.
Math Calculators
105 calculators
Free math calculators for percentages, geometry, statistics, algebra, and arithmetic. Step-by-step formulas for students, professionals, and everyday problem-solving.
Unit Conversion Calculators
90 calculators
Free unit converters for length, weight, volume, temperature, speed, area, energy, pressure, and data. Exact conversion factors with instant results.
Health & Nutrition Calculators
77 calculators
Free health calculators for BMI, BMR, TDEE, calorie intake, macros, body composition, and more. Built on clinically validated formulas like Mifflin-St Jeor and WHO standards.
Construction & Home Improvement Calculators
63 calculators
Free construction calculators for concrete, paint, roofing, flooring, fencing, and more. Estimate materials, costs, and quantities for any project.
Everyday Calculators
53 calculators
Free calculators for tipping, discounts, electricity costs, gas mileage, and daily life. Quick answers to common questions.
Business Calculators
50 calculators
Free business calculators for break-even analysis, employee costs, SaaS metrics, invoicing, pricing strategy, and customer lifetime value. Built for entrepreneurs and managers.
Science & Engineering Calculators
49 calculators
Free science calculators for physics, chemistry, and electrical engineering. Ohm's law, Newton's laws, ideal gas law, wave equations, and more.
Fitness Calculators
46 calculators
Free fitness calculators for strength training, running, cycling, and exercise planning. Estimate one-rep max, running pace, heart rate zones, and calories burned.
AI & Technology Calculators
43 calculators
Free calculators for LLM API costs, token counting, and AI training expenses. Plan AI project budgets with real pricing data.
Time & Date Calculators
30 calculators
Free calculators for age, dog years, cat years, days between dates, work hours, and countdowns. Precise date math with leap year support.
Cooking & Kitchen Calculators
28 calculators
Free cooking calculators for recipe scaling, measurement conversions, oven temperatures, baking adjustments, and coffee ratios. Essential kitchen math tools.
Education Calculators
27 calculators
Free GPA and academic planning calculators. Calculate your grade point average and evaluate the ROI of higher education.
Clean Energy & Sustainability Calculators
26 calculators
Free calculators for solar panels, energy savings, carbon footprint, and sustainable living. Estimate production, payback period, and environmental impact.
Auto & Transportation Calculators
24 calculators
Free auto calculators for fuel cost, EV savings, car depreciation, gas mileage, insurance estimates, and tire comparisons.
Sports
23 calculators
Free online sports calculators with instant results.
DIY & Home Improvement Calculators
21 calculators
Free DIY calculators for wallpaper, tile, mulch, carpet, topsoil, and home improvement projects. Calculate materials with waste allowance.
Travel Calculators
16 calculators
Free travel calculators for currency conversion, flight time estimation, road trip costs, time zone conversion, and hotel comparison. Plan smarter trips.
Shopping Calculators
13 calculators
Free shopping calculators to compare unit prices, calculate sales tax, stack coupon savings, and track subscription costs. Shop smarter.
Pets
12 calculators
Free online pets calculators with instant results.
Gaming
9 calculators
Free online gaming calculators with instant results.
Agriculture
9 calculators
Free online agriculture calculators with instant results.
Legal
8 calculators
Free online legal calculators with instant results.
Read the math behind the numbers.
All guides →Guides
Long-form explainers on mortgage affordability, TDEE, solar payback, compound interest, paycheck deductions, and more, each linking to the calculators that power them.
Glossary
Definitions of the financial, clinical, and engineering terms used throughout CalcIntel. Every entry cites the authoritative source, CFPB, CDC, NIST, EPA, WHO, and links to the relevant calculators.
Frequently asked.
How many calculators does CalcIntel have?
CalcIntel offers hundreds of free online calculators across 12+ categories including finance, health, math, construction, fitness, science, clean energy, and AI technology. Every calculator uses real formulas and provides instant results.
Are these calculators free to use?
Yes, every calculator on CalcIntel is completely free to use with no sign-up required. Results are calculated instantly in your browser, we never store your inputs or personal data.
How accurate are the calculators?
Our calculators use industry-standard formulas and are reviewed for accuracy. Financial calculators use standard amortization and compound interest formulas. Health calculators use clinically validated equations like Mifflin-St Jeor for BMR and WHO standards for BMI. Each calculator page explains the formula used.
What categories of calculators are available?
CalcIntel covers Finance (mortgage, loan, investment, tax), Health (BMI, calories, pregnancy, GLP-1), Math (percentage, geometry, statistics), Construction (concrete, paint, roofing), Fitness (TDEE, macros, running pace), Science & Engineering, Time & Date, Unit Conversions, Auto & Transport, Education, Clean Energy, and AI & Technology.
Can I use these calculators on my phone?
Yes, all CalcIntel calculators are fully responsive and work on any device, phone, tablet, or desktop. Inputs update results in real-time with no page reload needed.
How do I use a calculator on CalcIntel?
Simply browse or search for the calculator you need, enter your values in the input fields on the left, and see results instantly on the right. Every calculator includes a detailed explanation of the formula, step-by-step instructions, and frequently asked questions to help you understand your results.