Free Online Calculators

Age Calculator

Calculate your exact age in years, months, days, hours, and minutes from your date of birth. Find out how many days until your next birthday. Free online age calculator.

Date Calculator

Add or subtract days, weeks, months, or years from any date to find a future or past date. What date is 90 days from today? What was 6 months ago? Free online date calculator.

Final Grade Calculator

What do I need to make on my final to get an A this semester? This final grade calculator will tell you.

Linear Grade Curve

This online grade curve calculator makes it a little easier to get your students' grades where you think they should be using a linear redistribution curve.

Square Root Curve

A square root, or Texas curve is a quick and easy way to help all students, but help the lower scores a little more

Teacher's Grading Calculator

Online version of the classic EZ Grader Calculator to take the place of grading charts. Enter a question count and max score. This online grade calculator will take care of the rest.

Test Corrections Calculator

Do you allow your students to do test corrections for partial credit? Here is an online calculator to make it easier.

VLSM Calculator

Free VLSM calculator for network subnetting. Calculate optimal subnet allocation with variable length subnet masks. Get network address, CIDR, netmask, usable IP ranges, and broadcast addresses.

Work Days Calculator

Count the number of working days between two dates, excluding weekends and optional public holidays. Free business day calculator for deadlines, contracts, and project planning.

About These Calculators

These free online calculators cover a wide range of everyday needs — from quick math and unit conversions to specialized tools for teachers, students, and professionals. Every calculator runs entirely in your browser, so there's nothing to install and no data is sent to any server.

How to Use Any Calculator

Each calculator is designed to be self-explanatory: fill in the fields, and results appear instantly or after clicking a calculate button. If you're unsure what a field means, most calculators include a short description or example alongside the inputs.

Types of Calculators Available

• Math calculators — arithmetic, percentages, exponents, roots, and other core math operations
• Education and teacher tools — grade calculators, curve calculators, and classroom-focused tools
• Date and time calculators — find the number of days between dates, calculate future or past dates, and work with time intervals
• Networking calculators — subnet masks, VLSM, CIDR, and IP address tools for network engineers and students
• Image tools — compression, conversion, and color tools for working with images
• Text tools — encoding, hashing, formatting, and other text utilities

Frequently Asked Questions

Are these calculators free?
Yes, completely free with no account required. Every tool on this site is available to anyone without sign-up or payment.

Do these calculators store my data?
No. All calculations happen locally in your browser. Nothing you enter is transmitted or stored on any server.

Can I use these on mobile?
Yes. All calculators are designed to work on phones and tablets as well as desktop browsers.

How accurate are the results?
Results are computed using standard JavaScript math, which uses 64-bit floating-point arithmetic (IEEE 754). For most practical purposes this is more than sufficient. For high-precision financial or scientific calculations, verify results with a dedicated tool.