Free study calculators
45 of them, across chemistry, physics, maths and grades. Every one does the same thing most calculators do not: fill in what you know, leave the unknown box empty, and it works out whichever value is missing — not just the one on the left of the equals sign.
Nothing is uploaded and no account is needed. The arithmetic happens in your browser, which is why there is no limit on how many times you use them.
chemistry · 14
Solutions, gases, reactions and the conversions every other chemistry question is built on.
physics · 15
Motion, forces, energy and circuits — the equations that come back every term.
maths · 13
Areas, volumes, lines and interest, each rearranged for whichever value you are missing.
grades · 3
What you scored, what you still need, and whether the target is actually reachable.
Why these are different
Most calculator pages compute in one direction. You get molarity from moles and volume, and if the question hands you the molarity and asks for the volume, you are back to rearranging it yourself on paper.
These do not work that way. Each one knows the whole relation, so leaving any single box empty makes that the answer. It is the same reason each page also names the mistake people actually make on that topic — volumes in millilitres, temperatures in Celsius, a radius confused for a diameter — because that is the part a formula lookup will not tell you.