Simple calculators and converters
Fast, accurate results for everyday tasks. No registration or complicated setup.
Examples below — click here and start typing
Tool categories
Pick a category to find the tool you need
Finance
Calculators and converters for financial calculations
Percentage Calculator
Calculate percentages, discounts, and markups
Currency Converter
Convert between different currencies
Loan Calculator
Calculate monthly payments and amortization schedule
VAT Calculator
Add or extract VAT from any amount online
Discount Calculator
Calculate the price after discount and your savings
Unit Price Comparison
Compare value across different package sizes
Compound Interest Calculator
Calculate deposit and investment returns
Health
Tools for calculating health metrics
BMI Calculator
Calculate body mass index
Ideal Weight Calculator
Calculate optimal weight by height
Daily Water Intake Calculator
How much water you should drink per day
Heart Rate Zone Calculator
Training heart rate zones
Walking Calories Calculator
Calories burned while walking
Calorie Calculator
Calculate daily calorie needs
Alcohol Calculator
BAC and alcohol elimination time
Everyday Life
Tools for daily tasks
Fuel Consumption Calculator
Calculate fuel usage and trip cost
Gas Consumption Calculator
Convert m³, kWh, and MWh
Yes or No Generator
Random answer to a question
Age Calculator
Exact age and days until birthday
Days Between Dates Calculator
How many days between two dates
Grade Average Calculator
GPA for diploma or transcript
Due Date Calculator
Calculate pregnancy week and due date
Kitchen Unit Converter
Convert grams to cups and spoons
Clothing Size Calculator
RU and S–XL size from measurements or height and weight
Shoe Size Calculator
RU, EU, US, UK size from foot length
Cat Age Calculator
Cat age in human years
Dog Age Calculator
Dog age in human years
Physics
Physical unit converters
Length Converter
Convert meters, centimeters, feet, and more
Weight Converter
Convert kilograms, pounds, and other mass units
Temperature Converter
Convert between Celsius, Fahrenheit, and Kelvin
Time Converter
Convert hours, minutes, and seconds
Ohm's Law Calculator
Calculate current, voltage, and resistance
Electric Power Calculator
Calculate electric power
Mathematics
Math calculators and tools
Percentage Calculator
Calculate percentages, discounts, and markups
Quadratic Equation Solver
Solve equations ax² + bx + c = 0
GCD Calculator
Greatest common divisor of numbers
Exponent Calculator
Raise a number to a power
LCM Calculator
Least common multiple of numbers
Prime Factorization
Factor a number into primes
Long Multiplication
Multiply multi-digit numbers step by step
Area and Perimeter
Calculate properties of geometric shapes
Area Unit Converter
Convert m², hectares, ares, acres and more
Circumference Calculator
Circle perimeter from diameter, radius, or area
Random Number Generator
Random numbers within a range
Scientific Calculator
Advanced calculator with scientific functions
IT & Tech
Tools for developers and technical specialists
Text & Content
Tools for text analysis and SEO
Home & DIY
Calculators for renovation and construction
Paint Calculator
Calculate paint volume needed
Wallpaper Calculator
Number of rolls needed
Concrete Volume Calculator
Calculate cubic meters of concrete
Wood Volume and Weight
Cubature and weight by species and moisture
Log Volume and Weight
Log cubature by diameter and length
Laminate Flooring Calculator
Usage and laying patterns
Spoke Length Calculator
Spoke lengths for bicycle wheel building
Metal Weight Calculator
Weight of sheet, rebar, pipe and other stock
What is CalcGuru
CalcGuru.ru is a free catalog of calculators, converters and generators in Russian, English and Spanish. Tools run in the browser — no account, and form values are not sent to a server just to get a result.
At the top: text and classic calculators for quick expressions. Below: the full catalog with search. Tool pages include formulas, examples and limits where the number is only a guide.
How calculations work and what they are not
Most tools compute locally. After the page loads, you can get a result without constant server round-trips.
BMI, calories, loans and similar pages are reference helpers — not a diagnosis or a bank offer. Confirm decisions with a clinician, bank or accountant.
Maintained by GEM. Ideas and bugs: hello@calcguru.ru.
📂 Tool categories
Percentages, VAT/sales tax, discounts, loans, compound interest, unit price, currency converter
BMI, ideal weight, water intake, calories, alcohol BAC, heart-rate zones, walking burn
Fuel use, age, days between dates, clothing and shoe size, cat and dog age
Percentages, quadratic equations, GCD/LCM, powers, area & perimeter, area unit converter, scientific calculator
Length, weight, temperature and time converters; Ohm’s law, electric power
File size, character counter; paint, wallpaper, concrete volume
🎯 Example tasks
- 🛒 Shopping: calculate a discount, compare price per kilo, convert an amount to another currency.
- 💳 Loan & savings: estimate a monthly payment or return with compound interest.
- ❤️ Health: check BMI, daily calorie needs, or training heart-rate zones.
- 📚 Study: solve a quadratic equation, find the GCD of two numbers, count characters in text.
- 🔨 Renovation: estimate paint litres, wallpaper rolls, or cubic metres of concrete.
- 🔐 Security: generate a strong password or a random number for a giveaway.
⭐ Why CalcGuru
Every calculator is available immediately — just pick a tool
Tool pages include how the calculation works, examples, and tips
Responsive UI for smartphones, tablets, and desktops
Calculations run in the browser; passwords and text are not stored on the server
🚀 How to use the site
- Find a tool with search on the homepage or open Calculators, Converters, or Generators.
- Enter your data and tap calculate — the result appears on the same page.
- For quick math, use the text or classic calculator at the top of the homepage.
- A full page list is available in the sitemap.