Physics Formula Solver
Choose a formula, enter what you know, leave the unknown blank — solved instantly with the rearranged equation.
Fill in every value except one. The blank field is solved automatically.
Variables
Leave exactly one field blank to solve for it. All other fields must be filled.
Result
Too many blanks. Leave exactly one field empty.
v, u, a, t
About the Formula Solver
The Formula Solver turns the most-used physics and science equations into an interactive calculator. Instead of rearranging an equation by hand, you simply enter the values you know and leave the unknown blank — the tool detects which variable is missing, applies the correct rearranged formula, and shows both the symbolic rearrangement and the numeric result with units. It covers motion (kinematics), force and energy, momentum, electricity, density, waves and the ideal gas law, so it is ideal for homework, lab reports and exam revision.
How to use it
- 1 Select a formula from the dropdown — its equation is shown in the highlighted card.
- 2 Enter every value you already know in its labelled field, with its unit shown beside it.
- 3 Leave the one variable you want to find empty (it is marked as unknown).
- 4 Read the answer instantly, together with the rearranged formula and the substituted calculation.
How it works
Each formula has a hand-derived algebraic rearrangement for every variable. When you leave one field blank, the solver picks the matching rearrangement, substitutes your numbers, and evaluates it. For example, Ohm's law V = IR can be solved three ways: V = IR, I = V/R, and R = V/I. The tool also guards against invalid input: it warns if two or more fields are blank, if a value would divide by zero, or if there is no real solution (such as a negative square root).
Frequently asked questions
How do I solve for a specific variable?
Fill in every field except the one you want to find, then leave that field empty. The solver automatically rearranges the formula to compute the missing variable.
Which formulas are included?
Twelve essential formulas: three equations of motion, Newton's second law, kinetic and potential energy, momentum, Ohm's law, electric power, density, wave speed, and the ideal gas law.
Are units handled for me?
Each variable shows its SI unit, and the result is displayed with the correct unit. Enter all values in the units shown for consistent answers.
Why do I get an error message?
You will see an error if no field is blank, if more than one field is blank, if your values cause division by zero, or if there is no real solution. Adjust your inputs and the answer appears instantly.
Related tools
Pair the Formula Solver with the Equation Solver for algebra, the Graph Plotter to visualise relationships, the Percentage Calculator for everyday maths, and the unit converters to switch between measurement systems before plugging values in.