Online Calculators & Tools

Corrects serum sodium for hyperglycaemia by both the Katz 1.6 and the Hillier 2.4 factors, shows how far apart they are, and checks a rate of change.

Converts a slope between a percent grade, a 1-in-N ratio, an angle in degrees and a rise over a run, and checks it against the ADA and drainage limits.

Applies the ratio, root, integral, limit comparison and alternating series tests to a general term, with the limit, the verdict and the reason for each.

Prices a second home loan with its higher rate and down payment, prorates the mortgage interest deduction across the shared debt cap, and runs the rental-use test.

Finds the scale factor between two similar figures from matching sides, areas or volumes, and gives the area factor squared and the volume factor cubed.

Works out a couple's retirement number with the survivor case, two retirement dates and a horizon that runs to the second death rather than the first.

Works out how much of a radioisotope is left after a given time, the activity in becquerels or curies, the half-life from two readings, and a parent-daughter chain.

Sizes a pool pump properly: the flow your volume and turnover need, the total dynamic head the plumbing puts in the way, and what the power costs to run.

Counts the evolutions your candy allows, including the candy transferring gives back, the walking that closes a shortfall and what fits in a Lucky Egg.

Cuts real daylight and real night into twelve unequal hours each and names the Chaldean ruler of every one, from your coordinates and a UTC offset.

Works out what percent of a goal you have reached, and whether the pace is fast enough to finish by the deadline.

Exact Pot Limit Omaha equity for two to four hands from the flop, turn or river, plus a showdown reader that enforces the exactly two hole cards rule.

Estimates total-body skeletal muscle mass from Lee's MRI-validated anthropometric equations, with the skeletal muscle index and the real error band.

Works out the MELD 3.0 liver disease severity score, and the older MELD-Na, applying the published flooring, capping and dialysis rules to each lab value.

Post-judgment interest to any date, at the statutory rate you enter, simple or compounded, with partial payments applied to interest first.

Puts two heights side by side, gives the difference in feet, inches and centimetres, the ratio between them, and draws both to scale on one baseline.

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.