Converters & Calculators

One searchable directory of nine multi-purpose workspaces, covering 46 calculation modes without dozens of repetitive HTML pages.

Choose a workspace

🔄 Unit Converters

Eleven modes: length, mass, temperature, area, volume, speed, storage, time, pressure, energy and power.

🧮 Math Calculators

Nine modes: percentages, averages, median, standard deviation, GCD and LCM.

📆 Age & Date Calculators

Three modes: age, date differences and add or subtract days.

💰 Finance Calculators

Four modes: loan EMI, compound interest, simple interest and savings goals.

🎓 Education Calculators

Weighted grades, marks percentages and attendance targets.

📐 Geometry Calculators

Circle, triangle, rectangle and Pythagorean theorem.

📊 Statistics

Population variance, sample standard deviation, z-scores and combinations.

⚡ Physics

Force, kinetic energy, electrical power and density, with explicitly stated SI units.

💻 Computing

Binary and decimal numbers, data-transfer time and image dimensions.

Find a specific calculator

46 calculators

Why combine related calculators?

Related tasks belong together: one measurement workspace switches between units, while the math workspace handles percentage and arithmetic questions. This makes it easier to discover related functions without opening dozens of similar pages.

Reliable results and limitations

The calculators run locally in your browser and validate invalid or unsupported inputs. Results are displayed with practical precision. Financial calculations use simplified fixed-rate assumptions and are not individualized financial advice. Calendar calculations use UTC dates, not time-zone-aware business deadlines.

Frequently asked questions

Are these converters free?

Yes. The workspaces do not require registration or payment.

Do I need to upload any information?

No. Inputs are evaluated locally and are not submitted as calculation requests to an OpenToolKit server. Advertising and third-party page resources may still make separate requests; see the privacy policy.

Using these calculators responsibly

Select a subject and then a calculation mode. Each mode identifies its inputs and the units or model it uses. Check the required input ranges and verify important outputs. Currency and loan results are simplified estimates and do not include every fee, tax or contractual condition.

The workspaces are designed to handle multiple related calculations on one page; use the directory search to jump to a mode. You can also copy a mode link to share the calculator without sharing personal inputs.

Have you found a mathematical mistake? Report it to us with the mode name, entered values and expected result. Please avoid including personal financial or medical information.