Online Calculators & Tools

Estimates GRE Verbal and Quantitative scores from a raw count using one stated linear rule, and works out what the second section has to reach a target.

Works out the glucose ketone index from a blood glucose and a blood ketone reading, converts mg/dL to mmol/L, and names the band the result falls in.

Turns a run of wall into a priced framing takeoff: studs, plates, headers, sheathing, fasteners and labour, with every rate an input rather than a guess.

Works out force five ways: Newton's second law, weight under any gravity, friction on a slope, centripetal force in a turn, and a spring under Hooke's law.

Works out what is genuinely left for an engagement ring after the wedding, the honeymoon, a deposit and everything else the same money owes. No suggested price.

Turnover rate from separations and average headcount, annualised, split into voluntary and involuntary, with a separate costing of what a replacement takes.

Kinematic displacement: how far an object ends up from where it started, from velocity and acceleration or from the legs of a journey, with the distance travelled beside it.

Scores a decathlon from the World Athletics tables: all ten marks, one event on its own, or the mark a points target needs.

Debt yield from net operating income and loan amount, sized against loan to value and debt service coverage so you can see which of the three tests binds.

Works out days payable outstanding from payables and cost of sales, then sets it beside days sales outstanding and days inventory in the cash conversion cycle.

Finds the weekday of any date by Zeller's congruence or the doomsday rule, handling the Julian to Gregorian switch that trips up most date tools.

Converts chmod permissions between octal and symbolic, builds a mode from tick boxes, and shows what each bit means on a directory as against a file.

Reactions, shear, bending moment and deflection for a simply supported span or a cantilever under a uniform load, a point load, or both.

Inverse tangent in degrees, radians and gradians, with the principal value, the full family of angles, and the two-argument atan2 form.

Typing speed in words per minute from a passage or a character count, with gross and net WPM, the error penalty, accuracy, CPM and keystrokes per hour.

Estimates what a website costs to build from its pages, features, CMS and store, then sets that one-off price against hosting, licences and maintenance every year.

Wavelength from frequency or frequency from wavelength, for light or sound in any medium, with the period, wavenumber, photon energy and the band it falls in.

Prices a vinyl floor from your own rates, by the box for plank and tile or by the square yard for sheet, with adhesive, underlayment, labour, trim and tax.

Sheet vinyl off the roll with both orientations worked out: strips, linear feet and yards, where the seams land and what is left over, plus glue-down adhesive.

Propagates measurement uncertainty through sums, products, powers and single-variable functions, and quotes the result rounded to the uncertainty's own digit.

Solve a trapezoid completely: height, area, perimeter, median, both diagonals and all four angles, from the four sides or from a base angle.

Picks a standard kVA rating from the connected load, single or three phase, then gives the full-load currents, the fault current and the NEC 450.3(B) protection.

Turns a title lender's monthly fee into an APR, totals the fees across every rollover, and shows how much vehicle equity the title puts at risk.

Work percentages on durations rather than plain numbers: what share one length of time is of another, a percentage of a duration, and h:mm:ss in and out.

Work out how far a material grows when it is heated, in length, area or volume, and the force it develops when both ends are held fast.

Weight of a plate blank once it is cut: rectangles with holes deducted, discs and rings, plus how many blanks nest on a sheet and what the drop-off weighs.

Solves q = m c dT for heat, mass, specific heat or temperature change, with an editable table of thirty materials, a mixing mode and the water heating curve.

Saturn's long transit over the natal Moon, with the three phases dated, the periods either side, and Kantaka Shani and Ashtama Shani. Entertainment only.

Convert parts per million to ppb, ppt, percent, mg/L, g/L, mg/kg and grains per gallon, work ppm out from a mass of solute, or cross to molarity.

Estimates how fast a pool loses water by the ASHRAE form of the Carrier equation, with the water it costs, the heat it carries away and what a cover saves.

Mortar for repointing brick or block: joint width times the depth raked out times the linear feet of joint, with bags, sand, cement and lime.

Works out the farrowing date from the service date on the 114 day swine average, with a window either side, the three-three-three rule and the usual herd calendar dates.

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%.