Watch calculations make sense. Explore animated explanations of conversions, measurements and formulas, with worked examples and the assumptions behind each answer.
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Finance
Understand prices, rates and everyday financial calculations through worked examples.
Health and Fitness
See how health and fitness measurements are calculated, with their assumptions and limits explained.
Physics and Math
Make sense of units, flow rates, engine measurements and mathematical relationships.
Miscellaneous
Discover practical calculations that do not fit neatly into the other collections.
Start with these explainers
CC to horsepower: why there is no exact conversion
See why displacement is not power, build a hypothetical horsepower range, and check it against the idea of a tested engine rating.
Waist-to-height ratio: measurement and calculation explained
Follow the measurement landmarks, match the units, and calculate waist as a share of height with adult screening context.
How to convert m³/h to CFM
Follow an airflow through a cubic-volume conversion and a 60-minute time change, then check the answer in reverse.
How to convert m³/h to GPM: US and imperial gallons
Convert a pump flow step by step and see why US and imperial gallons give different counts for the same water.
How to calculate price per square meter
Divide property prices across equal squares of area, compare two examples, and multiply back to verify the result.
More calculation explainers
How to calculate shelf life and time remaining
Calculate elapsed days, remaining days and percentage remaining with a moving calendar timeline. The example also explains why calendar arithmetic cannot establish product safety.
Carpet area: estimates, measurements, and the 70% rule
See the difference between estimating carpet area from a built-up area and measuring usable floor space directly. Animated floor plans show both approaches and their limits.
How to calculate movie end time
Add a movie runtime to its start time, account for trailers, and handle a finish after midnight. A clock and elapsed-time ribbon make each step visible.
Calorie deficit calculations: the math and its limits
Understand calorie-deficit arithmetic, the assumptions behind an estimated energy gap, and why a static calculation does not promise a particular weight change.
How to convert millimeters to fractional inches
Convert millimeters to decimal inches, round to a chosen ruler subdivision, and measure the rounding error. Animated subdivisions show why precision changes the answer.
How to calculate pay from hours worked
Turn hours and minutes into decimal hours, calculate gross pay, subtract unpaid breaks, and handle a separately specified overtime rate.
How to convert sheet-metal gauge to millimeters
Learn why sheet-metal gauge must be looked up in a material-specific table before converting the listed thickness to millimeters. The same gauge number can mean different thicknesses.
Foot length and shoe size: how the conversion works
Measure heel-to-toe foot length and see what a simplified shoe-size formula can—and cannot—tell you. The animation explains unit conversion, sizing offsets and brand-specific fit.
How to calculate and compare price per gram
Compare packages fairly by dividing total price by net mass. Animated packages and equal-mass comparisons distinguish dollars per gram from cents per gram.
Calorie surplus calculations for bulking: the math
Calculate a hypothetical calorie surplus as a percentage of a maintenance estimate. Animated energy blocks explain the arithmetic and why it cannot predict muscle gain.
More calculation explainers
How to calculate weight difference and percent change
Subtract two measurements, interpret the sign, and calculate percentage change using the starting value. Animated scales and number lines make the difference between direction and magnitude visible.
How to calculate weight from BMI and height
Rearrange the BMI equation to find the weight corresponding to a chosen BMI and height. A height-squared diagram explains the unit conversion and the most common algebra mistakes.
How to convert kilograms to viss
Convert kilograms into the traditional Myanmar unit viss, reverse the calculation, and understand how rounded conversion factors affect the result.
Wheel horsepower to engine horsepower: the calculation
Use an assumed drivetrain loss to estimate engine power from wheel horsepower. A power-flow diagram shows why dividing by the retained fraction differs from adding a percentage.
How to calculate kilograms from a length in feet
Calculate mass from a length and a matching mass-per-length specification. Animated cable segments explain why feet alone cannot convert to kilograms.
Urine osmolarity and osmolality: the calculation
Build a urine osmolarity estimate from solute concentrations, follow the units through a worked example, and distinguish the calculated value per liter from measured osmolality per kilogram of water.
How to calculate mass from dimensions in centimeters
Turn centimeter dimensions into volume, multiply by density, and convert grams to kilograms. A building block animation explains cubic units and how hollow space changes the answer.
How to convert milliliters to units
Use concentration to connect milliliters with activity units. Equal-volume containers show why the same volume can contain very different amounts.
How to estimate calories used during sleep
Work through a rough sleep-energy model and see how body weight, time and an assumed rate affect the answer. The explanation distinguishes arithmetic precision from biological accuracy.
How to calculate and compare price per kilogram
Convert package mass to kilograms, calculate unit price, and compare different package sizes on an equal-mass basis.