Density, Force and Pressure: Units That Need Care
A guide to common science and engineering calculations where units make or break the result.
Science tools
Science and Engineering Calculators
Practical tools for physics, chemistry, units and technical formulas, designed for quick checking and repeat use.
Science and engineering calculators depend on the right unit as much as the right formula. A result can look precise while still being wrong if the input unit, scale or context is mixed.
These calculators are designed for quick checks across units, electricity, motion, chemistry and technical formulas. Use the answer as a practical estimate, then verify critical work against the relevant standard or source.
10 calculators
Check common science and engineering formulas with visible units, assumptions and result notes.
ScienceUnit ConversionConvert common length, weight, temperature and volume units with instant results.ScienceOhm's LawCalculate voltage, current, resistance or power from any two known electrical values.ScienceSpeed Distance TimeCalculate speed, distance or time when you know the other two values, with clear units for travel, sport and science checks.ScienceDensityCalculate density, mass or volume when you know the other two values, with unit notes for science and engineering checks.ScienceForceCalculate force from mass and acceleration using Newton's second law, with results in newtons for physics checks.SciencePressureCalculate pressure from force and area, with pascal, kilopascal and bar estimates for science and engineering.ScienceMolarityCalculate molarity from moles of solute and solution volume, with concentration shown in mol per litre.ScienceDilutionCalculate stock solution volume using C1V1 equals C2V2, with final volume and dilution ratio shown clearly.SciencepHConvert hydrogen ion concentration to pH, or pH to hydrogen ion concentration.ScienceEnergyCalculate kinetic, electrical or heat energy using common formulas, with joule and kilojoule results where relevant.
Guides
Useful reading for science questions
Read the background, then move straight into the linked calculators when you need a result.
Concentration, Dilution and pH Calculations
How to think about molarity, dilution and pH when checking chemistry calculations.
Common Unit Conversion Mistakes and How to Avoid Them
How to avoid errors with length, weight, temperature, volume, density and pressure conversions.