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Body mass index with WHO category and healthy weight range for your height.

Basal metabolic rate (Mifflin-St Jeor) and daily calorie needs by activity level.

Future value with monthly contributions, yearly growth breakdown and chart-ready data.

Monthly payment, total interest and the full amortization schedule.

X% of Y, percent change and percent difference — with worked steps.

Exact age in years, months and days — plus days until your next birthday.

Posts, rails, pickets or panels and concrete for any fence run — metric or imperial.

Itemized import duty, excise and fees for importing a car into Georgia.

Estimated customs duty, VAT and fees for importing a car into Armenia.

Monthly payment, total interest and full cost of a home loan — with tax and insurance.

Tip amount, total and an even split per person for any bill.

Sale price and the amount you save from any percentage off.

Add sales tax or VAT to a price, or back it out of a tax-inclusive total.

Estimate a pregnancy due date, weeks along and trimester from your last period.

Running pace per km and per mile, plus speed, from a distance and a time.

Days, weeks, months and years between any two dates.

Mean, median, mode, range and more for any list of numbers.

Solve for speed, distance or time given the other two.

Credit-weighted grade point average on the standard 4.0 scale.

Interest earned and final balance with I = P × r × t — no compounding.

Body fat percentage from tape measurements using the US Navy method.

Ideal body weight by the Devine, Robinson, Miller and Hamwi formulas.

Simplify a ratio to lowest terms or solve a proportion for the missing value.

Population and sample standard deviation, variance and mean for a data set.

Combine two independent events — both, either, neither or exactly one.

Solve V = I × R for voltage, current or resistance, plus power in watts.

Newton's second law F = m × a — solve for force, mass or acceleration.

Solve ρ = m ÷ V for density, mass or volume in SI units.

Kinetic energy KE = ½ m v² — solve for energy, mass or velocity.

Add, subtract, multiply or divide two fractions — answer in lowest terms plus a decimal.

Solve ax² + bx + c = 0 — real or complex roots, the discriminant and worked steps.

Greatest common factor and least common multiple of any list of whole numbers.

Solve a right triangle (a² + b² = c²) from any two sides, with area and perimeter.

Radius, diameter, circumference and area of a circle from any one measurement.

Return on investment from an initial and final value, plus annualized CAGR.

The monthly deposit needed to reach a savings goal by a target date, with interest.

How inflation erodes purchasing power over time — or the future amount to keep value.

Add or subtract days, weeks, months or years from a date to find the resulting day.

Working days (Mon–Fri) between two dates, with weekend and calendar days shown.

Convert one pay figure into hourly, weekly, monthly and annual pay via an annual pivot.

Add VAT to a net price or remove VAT from a gross price at any rate, defaulting to Georgia's 18% standard, with a net / VAT / gross breakdown.

Enter cost and revenue to get profit, profit margin % and markup % — currency-neutral.

Total Daily Energy Expenditure: BMR (Mifflin-St Jeor) times an activity factor, giving the calories you burn per day.

Estimate a daily water target from your weight and exercise — about 33 ml per kg, plus a bump for activity.

Enter an initial (V₁) and final (V₂) value to get the signed percentage change between them — the calculator shows whether it is an increase or a decrease and reveals the full working.

Round a number to any decimal place — to the nearest, up or down.

Area = length × width × quantity, in feet (ft²) or meters (m²) — with the converted area shown in the other unit.

Work out how much paint to buy: litres = wall area × coats ÷ coverage. Enter the area in m², the number of coats and the paint's spread rate per litre.

Find the z-score (standard score) of a value from the mean (μ) and standard deviation (σ) using z = (x − μ) ÷ σ.

Concrete volume for a slab or footing: volume = length × width × (thickness ÷ 100) × quantity — enter length and width in metres and thickness in centimetres, and get cubic metres, litres and 25 kg bags.

Tiles = area ÷ tile area × (1 + waste) — enter the area in metres, the tile size in centimetres and a waste allowance for cuts.

Enter a base and an exponent to compute base ^ exponent — whole, negative and fractional powers are all supported, with the working shown.

Convert any number to scientific notation m × 10^n — mantissa, exponent and E-notation, with the working shown.

Calculate combinations (nCr) and permutations (nPr) for choosing r items from n. nPr = n! ÷ (n − r)! and nCr = n! ÷ (r! · (n − r)!), computed exactly with every step shown.

Find the kth percentile of a data set by linear interpolation (the R-7 method used by Excel and NumPy), with the sorted data, the rank and every step shown.

Split a daily calorie target into grams of protein, carbs and fat — enter your calories and the percentage for each macro.

Solve P = W ÷ t for power, work or time — enter the two values you have.

Solve P = F ÷ A — enter the force in newtons and the area in square metres to get pressure in pascals, kilopascals and bar.

Find the grade you need on your final exam to reach a target course grade, given your current grade and how much the final is worth.

Enter the time you must wake up or plan to go to bed — get times that land at the end of a 90-minute sleep cycle.

Estimate your ovulation date and most fertile days from your last period and average cycle length.

Hours between a start and end time, minus an unpaid break — in decimal hours and hours:minutes.

Enter trip distance, fuel consumption and price per litre to get the fuel cost — currency-neutral.

Compute log_b(x) for any positive base with the change-of-base formula log_b(x) = ln(x) ÷ ln(b) — the full working is shown.

Enter a number and a degree to find its nth root ⁿ√x — square root by default, with the working shown.

Slope, y-intercept, angle and equation of the line through two points, with m = (y₂ − y₁) ÷ (x₂ − x₁).

Find acceleration from a change in velocity over time — a = (v − u) ÷ t, also shown in g-force.

Solve W = F × d × cos(θ) — work from a force, the distance it acts over and the angle between them, in SI units.

Confidence interval for a population mean from the sample mean, standard deviation and size, with the margin of error.

Volume of a box, cylinder, sphere or cone from dimensions in cm — results in cm³ and litres.

Work out your overall course grade as the weighted average of assignment scores and the weight each one carries.

Estimate blood alcohol content with the Widmark formula from sex, body weight, standard drinks and hours since drinking — never drive after drinking.

Prime factors of any whole number in exponent form (60 = 2² × 3 × 5), with every division step and a prime check.

Maximum heart rate from 220 − age plus five training zones at 50–100% intensity, using percent-of-max or the Karvonen resting-heart-rate method.

Convert an integer between decimal, binary and hexadecimal — exact big-integer results with place-value steps.

Compute how much of a decaying substance remains from the initial quantity, half-life and elapsed time — with percent left and half-lives passed.

Calculate the Pearson correlation coefficient r between two paired data sets, with r², both means and a plain-language strength interpretation.

Find how many units you must sell to cover fixed costs — exact and rounded-up break-even units, revenue and contribution margin, currency-neutral.

Calculate the wavelength of light, radio or sound waves from frequency and wave speed using λ = v ÷ f, auto-scaled to km, m, mm, µm or nm.