Online Calculators & Tools

Sideways parabolas and the conic form: x = ay2 + by + c, or a focus and directrix, or a vertex and focus, with the curve drawn.

Calories eaten minus calories burned, with the resting metabolism that sits inside every exercise figure taken out so the day is not counted twice.

Transposes a matrix of any shape up to 8 by 8 by swapping its rows and columns, flags symmetry, and can also return the products A^T A and A A^T.

Area of any irregular polygon from a traverse of bearings and distances, or from side lengths with interior angles, with the closure error and a scale drawing.

Integrates a polynomial times e^(kx), sin(kx), cos(kx) or ln(kx) by parts, showing the choice of u and dv and every row of the table, indefinite or between limits.

Works out the profit on a house flip from the purchase, rehab, monthly holding costs, loan and selling costs, with the return on cash and the 70% ARV rule.

Finds the balance point where heat pump capacity crosses the heating load, the capacity left at the design temperature, and the backup heat needed below it.

Solves two or three linear equations by elimination and writes out every row operation, in exact fractions, with the answer checked in the original equations.

Finds where a polynomial's derivative is zero, classifies each point as a maximum, a minimum or neither, and gives the absolute extremes on an interval.

Works out what any craps bet pays on a given wager, alongside the true odds and the house edge that the published payout table implies.

Solves a 2x2 or 3x3 linear system by Cramer's rule, showing the coefficient determinant, each replaced-column determinant and the division that gives every unknown.

Concrete volume for a poured set of steps, worked from the total rise, tread depth and width, with riser sizing, bag counts and a stair code check.

Works out the published rule of thumb for prepared formula, about 2 to 2.5 fl oz per pound of body weight a day, split across feeds and capped at around 32 oz.

Puts two or three car finance offers side by side on the same vehicle, including the dealer choice between a subsidised low APR and cash back.

Prices an artificial turf installation line by line from your own rates: turf, base stone, infill, weed barrier, edging, seaming, labour and one-off charges.

Estimates an AP Seminar score from its three weighted parts: the team project at 20%, the individual research-based essay at 35% and the end-of-course exam at 45%.

Turns airflow and room size into air changes per hour, or a target rate into the CFM it needs, and reads a blower door test as ACH50 and a natural rate.

Works the air an engine needs in lb/min and the pressure ratio across the compressor, which together are the point you plot on a compressor map.

Surface area of a cube, box, sphere, cylinder, cone or square pyramid, split into the lateral area and the bases, in square metres, feet and inches.

Solves a two-variable linear system by substitution and writes out every step: the variable isolated, the expression substituted, the collecting, and the check.

Turns a screen diagonal and aspect ratio into width and height, works the throw distance from the projector's throw ratio, and places the seats.

Works out simple and discounted payback from a cash flow series, interpolating the part year, with the running balance for every period and a verdict against your cutoff.

Works out smoking pack-years from cigarettes or packs a day and the years smoked, and adds up several periods at different rates into one total.

Work out the MCA and the maximum overcurrent protection for air conditioning equipment from the motor currents, using NEC Article 440.

Work out enchanting table levels for any bookshelf count, anvil costs with the prior work penalty, and the experience between two levels in Java Edition.

Convert military time to the 12 hour clock and back, with the 0000, 2400 and 1200 midnight and noon cases handled, plus elapsed time past midnight.

Runs the Mann-Whitney U test on two samples, with the exact null distribution for small samples and a tie-corrected normal approximation for large ones.

Work out the Vimshottari mahadasha sequence from the Moon nakshatra, with the balance at birth, all nine periods and the antardashas. For entertainment.

Add up order lead time stage by stage, then work out the reorder point and safety stock from demand and lead time variability at a chosen service level.

Find the numerology karmic debt numbers 13, 14, 16 and 19 in a birth date or a name, with every step of the reduction shown. For entertainment.

Estimate how many days a flight will take to shake off from the time shift and its direction, and get a day by day light exposure schedule.

Differentiates a polynomial equation in x and y implicitly, giving dy/dx as an exact quotient, the second derivative, and the tangent line at a point.

Solve PV = nRT for pressure, volume, moles or temperature in your own units, run the combined gas law between two states, and get gas density from a molar mass.

Works out engine horsepower from torque and RPM through the 5252 relation, turns power back into torque, and converts a wheel figure into a crank figure.

Adds radon, sewer scope, termite, mould and re-inspection fees to the quoted base inspection, and shows how far the real bill sits above the headline number.

Turns seven heptathlon marks into IAAF points using the published scoring formulas, with the points for each event and the mark a points target needs.

Prices a gutter installation from your own per-foot rate, tear-off, guards, downspouts and corners, and turns a house footprint into linear feet and hangers.

Turns a CGM mean glucose into a Glucose Management Indicator and sets it beside a laboratory A1C, so the gap between the two becomes the number you read.

Adds a garage door replacement up from the door, hardware, labour, removal and permit you were quoted, and weighs repairing the old door against replacing it.

Fragrance oil weight for a given weight of candle wax at any load percentage, the same sum backwards, and the wax and oil a whole batch of containers needs.

Turn a fraction or a mixed number into a percentage, with the exact value when the division repeats, the lowest terms and the decimal alongside.

Convert a field of view between horizontal, vertical and diagonal at any aspect ratio, and carry a game FOV setting from a 4:3 or 16:9 base to your own screen.

Turn a target pounds of nitrogen per 1,000 square feet into pounds of an N-P-K product and bags to buy, or run it backwards from the bag you already have.

Name the face shape four measurements fall into, from forehead, cheekbone and jaw width and face length, with the rule that decided it printed alongside.

Transposes a prescription between plus and minus cylinder, reads out both eyes with the near power and spherical equivalent, and adds two lenses at different axes.

Crosses linear supply and demand curves to find the market price and quantity, with consumer and producer surplus and the effect of a tax or a price control.

Finds the empirical formula from a percent composition or a set of masses, shows every mole step, and gives the molecular formula when you add a molar mass.

The exact parts of an E6B: the wind triangle both ways, true airspeed and density altitude from the standard atmosphere, and leg time, fuel and reserves.