Most-Used Calculators & Tools
Deep-dive pages for the 15 most-used calculators on HelperTools. Each one includes the calculator itself plus a full explanation of how it works, when to use it, common mistakes, and answers to the questions people ask most. Everything runs in your browser — no sign-up, no ads between you and the answer.
Mortgage Calculator
Monthly P&I, total interest, and total cost for any loan amount, rate, and term.
Loan Payoff Calculator
Months to payoff and total interest on any loan with fixed or extra payments.
Compound Interest Calculator
How your savings grow over time with compounding and monthly contributions.
Tip Calculator
Tip amount, total bill, and per-person split for any party size.
Percentage Calculator
Solve any percent problem — what is X% of Y, X is what % of Y, and more.
Age Calculator
Your exact age in years, months, weeks, days, and more — from any birth date.
Unit Converter
Length, weight, temperature, volume, and speed — convert between any units.
Word Counter
Word, character, sentence, and paragraph count with reading-time estimate.
JSON Formatter
Pretty-print, validate, and minify any JSON payload — right in your browser.
Base64 Encoder / Decoder
Encode or decode any text or Base64 string with full Unicode support.
Password Generator
Secure, random, customizable passwords generated entirely on your device.
QR Code Generator
Turn any URL, text, phone, or Wi-Fi into a downloadable QR code.
BMI Calculator
Body Mass Index, category, and healthy weight range in imperial or metric.
Calorie Calculator
Your daily calorie needs using the Mifflin-St Jeor formula and activity level.
Pomodoro Timer
Focus timer with 25-minute work blocks and short/long breaks.
Looking for something else?
These 15 are our most-trafficked tools. We have 89 more across 10 categories. Browse by category: Financial · Everyday · Text · Dev · Time · Cooking · Generators · Construction · Health · Home Services.