Watch calculations make sense. Explore animated explanations of conversions, measurements and formulas, with worked examples and the assumptions behind each answer.
Browse videos by category
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.
More calculation explainers
How to convert µmol/L to mg/dL
Convert amount concentration into mass concentration by following the substance and every unit. A creatinine example shows where the factor of 10,000 comes from.
How to calculate words correct per minute
Separate correct-word rate from reading speed and accuracy. A timed passage demonstrates subtraction, seconds-to-minutes conversion, and the limits of a rate score.
How to calculate simple daily interest
Turn an annual rate into a daily amount, accumulate simple interest without early rounding, and distinguish day-count conventions from compounding.
How to calculate travel time from kilometers
Use distance and average speed to calculate time, turn decimal hours into minutes, and account for stops or different travel speeds.
How to convert price per kilogram to price per pound
Convert a kilogram unit price to a pound unit price using the exact mass relationship, then check a package total and compare equivalent offers.
How to calculate volume-based infusion rates
Learn the dimensional arithmetic behind volume per hour and drops per minute. A hypothetical example separates flow rate, tubing calibration and medication dose.
How to calculate GMI and compare it with A1C
Calculate GMI using the established 2018 equation, reverse the equation for its implied glucose mean, and distinguish the result from a separately measured laboratory A1C.
How to calculate length of service between dates
Count elapsed days and calendar years, months and days between two dates, with clear endpoint and leap-year conventions.
How to estimate stories from building height
Estimate stories from building height using an assumed floor-to-floor height. Animated examples show equal floors, partial remainders, a taller lobby and roof features that change the estimate.
How to divide money into equal shares
Divide a total into equal shares, handle a repeating decimal at cent precision, and check that rounded allocations still sum to the original money.
How to convert price per pound to price per kilogram
Convert a pound unit price to a kilogram unit price, understand why the number increases, and compare or check a package total without early rounding.
How to convert inch fractions to millimeters
Convert a fractional or mixed-number inch measurement to millimeters using the exact 25.4 mm per inch relationship. See the fraction and the metric length on the same ruler.
How to estimate paper thickness from GSM
Derive paper thickness from mass per area and density, track the square-centimeter conversion, and see why equal GSM does not guarantee equal thickness.
How to convert surface speed to RPM
Turn linear speed at a rotating surface into revolutions per minute by finding the distance traveled in each revolution. Follow diameter units and compare two wheel sizes.
How to estimate distance from liters of fuel
Estimate distance using either kilometers per liter or liters per 100 kilometers, recognize their reciprocal relationship, and keep usable fuel and real-world variation visible.
How to calculate price per 100 grams
Normalize different package sizes to an equal 100-gram basis, compare the unit prices, and check how net weight and waste affect the decision.
How to convert motor horsepower to kVA
Distinguish shaft horsepower, electrical real power, and apparent power. Work a 10 hp example with 90% efficiency and 0.8 power factor, and see why the idealized shortcut is lower.
How to convert minutes into money at an hourly rate
Convert an hourly rate to a per-minute amount, price a 25-minute interval, reverse-check the result, and scale the same method to a small meeting.
How to convert lb/hr to GPM using density
Bridge mass flow and volume flow with fluid density, work 600 lb/hr of water at an approximate room-temperature density, then contrast a lighter fluid and reverse-check units.
How to calculate percentage of a target achieved
Turn actual-versus-target into an achievement percentage, reverse-check a 75% example, show results above 100%, and distinguish lower-is-better budget measures.
How to find kilograms from inches, area and density
Learn why inches cannot directly become kilograms, then use cross-sectional area and material density to calculate the mass of a ten-inch steel bar.
How to estimate StairMaster calories burned
Follow a cited 9.3-MET stair-treadmill estimate for a 70 kg person over 30 minutes, then separate gross from above-rest calories and see why machine level is not a universal calorie rule.
How to calculate battery health percentage
Compare current full-charge capacity with original design capacity to calculate capacity-based battery health, and separate that long-term measure from today's charge level.
How to calculate three-phase power
See why √3 appears in a balanced three-phase calculation, work through 400 V and 100 A at 0.8 power factor, and separate kVA, kW and kVAR.
How to convert grams to viss
Convert between grams and Myanmar viss by dividing or multiplying by about 1,632.93 grams per viss, then verify a two-viss example and distinguish mass from liters.
How to calculate tons of material from square feet
Turn a measured footprint and layer depth into volume, then use a material’s quoted density to estimate U.S. short tons. See a five-ton example and why cooling tons are different.
How to convert FTE to hours
Convert a full-time-equivalent ratio to hours using a stated full-time schedule. At 40 hours per week, 0.75 FTE means 30 hours; with a 35-hour standard, it means 26 hours 15 minutes. Includes reverse checks and weekly versus annual assumptions.
How to calculate money per second from annual income
Convert annual income into an average dollar or cent rate per second. A $72,000 example compares all 365 days with a 40-hour, 50-week working schedule, showing how the chosen denominator changes the result.
How to calculate 48 hours from a starting time
Learn how to add 48 elapsed hours to a starting instant, convert the result to a named time zone, and distinguish that interval from two calendar days when daylight saving time changes.
How to find cube side length from mass and density
Learn why kilograms cannot convert directly to centimeters. Use density to find volume, then take the cube root to find the side length of a uniform cube, with an 8 kg worked example.
How to convert newtons to kilograms using gravity
A newton is force and a kilogram is mass. Learn when weight can reveal mass, divide by the local gravitational acceleration, check a 196.2 N example, and see why a push is different.
How to convert air watts to pascals using airflow
Air watts and pascals measure different quantities. Use airflow at the same operating point to estimate pressure difference, follow a 120 AW and 20 L/s example, and see why a sealed inlet or different flow changes the answer.
How to calculate employment duration between dates
Calculate the elapsed calendar days between employment dates, understand leap-year anniversaries, and choose the correct rule for inclusive days or workdays.
How to calculate a square-root grade curve
See why a square-root curve maps a 64% raw grade to 80%, how its boost varies across scores, and how to reverse-check the result.
How to calculate half-day time and a midpoint
Find half of a work duration, add it to a start time, and distinguish that from the midpoint of an entire clock interval. An eight-hour shift, a break, and an overnight example show when the answers differ.
How to calculate growth rate and CAGR
Distinguish total percentage growth from a compounded rate per period. Follow a 1,000-to-1,500 example over five years, check CAGR backward, and see why simple averages and reversed changes differ.
How to convert HBW to HRC for steel
Understand why Brinell and Rockwell C conversion depends on the material. A steel table lookup and a 300 HBW interpolation show an approximate 32 HRC result, sensible rounding, and the limits of converted values.
How to calculate aldosterone-to-renin ratio (ARR)
Learn the order of the aldosterone-to-renin ratio and its reciprocal, with a complete PRA example, unit conversion, denominator sensitivity and laboratory interpretation limits.
How to calculate loan payments and total interest
Calculate a fixed-rate loan payment, follow the changing interest and principal split, and compare monthly payments with lifetime interest using a complete $20,000 example.
How to calculate calorie needs: resting energy, TDEE and deficits
Build a daily energy estimate from the Mifflin–St Jeor equation, compare activity assumptions, and calculate an illustrative calorie deficit without confusing resting energy with a universal minimum intake.
Can you convert L/min to psi? Flow rate and pressure explained
Learn why L/min cannot directly convert to psi, then calculate an ideal water-nozzle pressure difference with complete unit conversions, Bernoulli arithmetic and a same-flow comparison.
How to calculate height-to-weight ratio (and why it is not BMI)
Follow a measured height and weight through the ratio, reverse-check the units, compare different inputs and unit systems, and see why height ÷ weight differs from BMI.
How to convert inches to decimal feet
Convert whole and fractional inches into decimal feet with an accurate twelve-inch ruler, a 5 ft 7⅜ in worked example, reverse check and rounding guidance.
How to convert human age to vampire age (a fictional rule)
Explore a fictional human-to-vampire age rule with an animated pair of timelines. Build the formula from its anchor and ten-to-one change, calculate 30 → 220, and reverse the result.
How to calculate a liquid dilution ratio
Name the concentrate-to-water ratio, count its equal parts, size a 22-fluid-ounce batch, check the mix, and distinguish product share from active-ingredient concentration.
How to convert GSM to kilograms
Learn why grams per square metre needs an area to become kilograms. Follow a 200 GSM fabric example, handle multiple pieces and check the units.
Can you convert centimeters to pounds? The missing measurement
Length alone cannot determine mass. Build pounds from a chain's length and linear density, verify the units and arithmetic, compare two materials, and see the separate volume-and-density route.