Free browser calculators
OpenCalcHub
Free, fast, and private. Every tool runs in your browser — no account, no wait.
Featured calculators
The first tools live on the site. More coming soon.
Tip Calculator
Calculate tip amount, total bill, and per-person split for restaurants or delivery. Enter the bill, pick a tip percent, and see what everyone owes — instantly.
Bill Split Calculator
Split an uneven restaurant bill and tip by person. Each person enters their share, adjusts tip in dollars or percent, and sees exactly what they owe.
Percentage Calculator
Find percentages, percent change, and what percent one number is of another. No spreadsheet needed.
Age Calculator
Find exact age in years, months, and days from a birth date. Includes total days lived and next-birthday countdown — leap years handled.
Date Difference Calculator
Count years, months, weeks, and days between two dates. Live countdown when the end date is in the future.
Recipe Converter
Convert kitchen measurements and scale recipes by servings. Cups, tablespoons, milliliters, ounces, grams, and more — instantly.
GPA Calculator
Add courses with letter or percentage grades and credits. Get a live unweighted 4.0 GPA or weighted GPA (up to 5.0 for Honors/AP).
Fuel Cost Calculator
Estimate trip fuel needed and gas cost from distance, MPG or L/100km, and fuel price. Supports round trips and US or metric units.
Overtime Calculator
Calculate regular pay, overtime pay, and total wages from your hourly rate, hours worked, and overtime multiplier. Accurate to the cent — free and instant.
BMI Calculator
Calculate your Body Mass Index from height and weight in imperial or metric units. See your BMI number, category, and a simple chart — free and private.
Mortgage Calculator
Estimate your monthly mortgage payment, total interest, and total cost from loan amount, rate, and term. Optional down payment and a clear amortization summary.
Pregnancy Calculator
Find out how many weeks pregnant you are from your last period, conception date, or due date. See trimester, estimated due date, and days remaining — free and private.
Browse by category
Jump to a topic and filter the full list.