Online Calculators & Tools

Dot product of two vectors in 2D or 3D, with both magnitudes, the angle between them, the projection of one onto the other and an orthogonality check.

Gallons of deck stain from the floor area plus the real surface of the railing, balusters and posts, at coverage rates for smooth or rough wood and for each coat.

Works out the challenge rating of a home-made D&D 5e monster from its hit points, armour class, damage per round and attack bonus, by the 2014 DMG table.

Critical values for the z, t, chi-square and F distributions at any alpha, one tailed or two, with the rejection rule and the confidence level spelled out.

Glucocorticoid equivalency reference: equal anti-inflammatory doses of prednisone, methylprednisolone, dexamethasone, hydrocortisone and the rest, side by side.

Estimates corn yield in bushels per acre by the yield component method, from an ear count in a measured length of row, kernels per ear and the kernel size factor.

Works out a year of credit card cash back from your own category rates and caps, compares a fee card against a no-fee one, and spreads a sign-up bonus over year one.

NEC 314.16 box fill: conductor, clamp, device, fitting and grounding allowances by wire size, against the cubic inches of a standard or marked box.

Places one systolic and diastolic reading in its 2017 ACC/AHA category, applying the higher-category rule, and gives the pulse pressure and mean arterial pressure.

Adds up the fourteen Berg Balance Scale items out of 56 and places the total in its published fall-risk band, with the tasks losing the most points named.

Estimates installed baseboard cost from room perimeters less door openings, with a mitre allowance, waste, whole sticks, labour, removal and painting.

Averages a set of blood pressure readings and gives the ACC/AHA category of the average, the spread, and the gap between the first reading and the rest.

Reduces an augmented matrix to reduced row echelon form and reports both ranks, whether the system is consistent, and the full solution set.

Net free ventilating area for an attic under the 1/150 and 1/300 rules, split between soffit intake and ridge exhaust and turned into a vent count.

Finds the vertical, horizontal and slant asymptotes of a rational function, separates holes from asymptotes, and sketches the curve with the lines drawn on it.

Works out acceleration from a change in velocity and time, from distance and time, or from net force and mass, and reports it in g as well as SI.

Projects a 529 college savings account forward, sets it against what college will cost by then, and prices what the tax free growth is worth.

Adds up a water well from your own quoted rates: per-foot drilling and casing, pump, pressure tank, wiring, trenching, permits, testing and contingency.

Finds the ISO 8601 week number of any date, and turns a week number back into its seven dates, handling the years that carry 53 weeks.

Works out what is left for a wedding gift from your own budget once travel, accommodation, outfit and gifts already given are taken off. No suggested figure.

Works out a vertical jump from hang time or from standing reach and touch height, then estimates jump power with the named Sayers and Lewis formulas.

Prices a metered utility bill on tiered block rates, separating the fixed charges so the true marginal cost of the next kWh, therm or gallon is visible.

Volume of a pyramid with a triangular base, from the base and height of that triangle, its three sides, an equilateral side or a regular tetrahedron edge.

The vibrating string equation solved three ways: tension from pitch, pitch from tension, and both from a wire's material and diameter.

Tests whether a gap between two conversion rates is real. Gives the z score, the p value, a confidence interval on the difference, and the sample size a test needs.

Draws your paired data as a scatter plot with the least squares line on it, and gives r, r squared and the residual left at every single point.

Compares keeping a house as a rental against selling now and investing the proceeds, over the years you would hold it, with the cost of being a landlord included.

Splits rent between housemates by room size, by income or by the nights each person is there, with names kept and the odd cent given to somebody.

Works out the diluent to add to a powdered vial for a concentration you want, and the volume that carries a stated amount once it is mixed.

Gallons or litres a roof will collect from its footprint, the rainfall and a collection efficiency, plus the tank volume a dry spell of a given length needs.

Plans the quilt top: block count and cut size with seam allowance, sashing and cornerstones, border strips, and the yardage each colour needs.

Molecular weight of a protein from its one-letter amino acid sequence, with the monoisotopic mass, molecular formula, extinction coefficient at 280 nm and theoretical pI.

Concrete and bag counts for fence or deck post holes, with the post and the gravel base taken out of the volume instead of paid for.

Counts what a set of attacking types hits for super effective damage across the 18 pure types and all 153 dual typings, and ranks the combinations that cover most.

Weight of pipe per foot and for the whole run, from a nominal size and schedule, from a copper tube type, or from an outside diameter and wall you measured.

Percent yield from the actual and theoretical yield, and the theoretical yield itself from the limiting reagent, its molar mass and the balanced equation.

Builds the installed cost of a paver patio line by line, from pavers and base to labour, demolition, haul away, tax and contingency, and weighs a quote against laying it yourself.

Divides PaO2 by FiO2, takes mmHg or kPa and per cent or fraction, applies the altitude correction and reads off the Berlin severity band for ARDS.

Prices a seller financed note from the seller's side: the monthly payment, the balloon, the interest you earn on it, and what a note investor would pay for it.

Writes the molecular, total ionic and net ionic equation for a precipitation or neutralisation reaction, names the spectator ions and gives the solubility rule used.

Works out a player's Little League age for baseball or softball from a date of birth, and lists the divisions that league age is eligible for.

Prices a mowing visit from the grass that is actually cut, taking the house and the driveway off the lot, then adds trimming, edging and the cleanups for a whole season.

Works out the Kelly stake from the odds on offer and the probability you think is right, in decimal, American or fractional form, with fractional Kelly and the growth rate.

Adds up an HVAC replacement from your own quoted rates: equipment, labour hours, duct work, line set, permit, removal, tax and rebates, with the cost per ton.

Prices a cleaning visit by floor area, by room count or by the hour, with the depth of clean, the recurring discount and every rate left as an input.

Sets a horse's daily forage and concentrate as a percentage of bodyweight for its workload, checks it against the published NRC ranges and plans a gradual change.

The great-circle midpoint between two latitude and longitude pairs, with the distance, the bearing from each end, and the point at any fraction of the route.

Morning and evening golden hour, blue hour and the three twilights for any date and place, worked out from the sun's altitude rather than a rule of thumb.