Online Calculators & Tools

Works out the dollars per paycheck and the deferral percentage that reach your 401(k) limit, with the age 50 and 60 to 63 catch-ups and the additions cap.

Solute potential from -iCRT plus pressure potential, in bars and megapascals, with the direction water moves between two solutions.

Size a storage tank from its first hour rating and peak hour demand, or a tankless unit from flow and the temperature rise your groundwater forces.

Volumetric flow rate from pipe or duct area and velocity, or from a volume and the time it took, in gpm, cfm, litres per second and cubic metres per hour at once.

Surface area of a triangular prism from the three sides and the length, with the area of every face, the volume and a scale drawing of the unrolled net.

Score an ATI TEAS practice test: percent correct in each of the four sections, overall, and the band your reported total has to fall inside.

Works out systemic vascular resistance from mean arterial pressure, central venous pressure and cardiac output, with the indexed figure and the pulmonary variant.

Lays two birth charts over each other, computing every planet, the lunar node and the angles for both, then listing each aspect between the two charts with its orb.

Weight of round bar, square bar, flat, plate, pipe, tube, angle and I beam in steel, stainless, aluminium and more, per foot and for the whole order.

Turns the watts or kilojoules an indoor bike reports into calories burned, with the resting share separated out and the implied MET shown.

The installed cost of a sodded lawn: sod, old turf removal, ground prep, labour, delivery and tax, plus a contractor quote against doing it yourself.

Writes a line as y = mx + b from a slope and a point, two points or standard form, and builds the parallel and perpendicular lines through any point.

Measure your own reading speed in words per minute from a timed passage, a word count or a number of pages, with the comprehension check.

Graph a parabola and get its vertex, axis of symmetry, intercepts, completed square, focus and directrix as exact values rather than read off the picture.

Draws the Punnett square for a one-gene or two-gene cross and gives the genotype ratio, the phenotype ratio and the percentage behind every box.

Multiplies two polynomials term by term, collects the like terms and returns the expanded product with its degree and leading coefficient.

Profit and loss at expiry for the basic option positions: long or short calls and puts, covered calls and vertical spreads, with break-even and the most you can make or lose.

Compares two or three mortgage offers on rate, term, points and fees, finds the cheapest over the horizon you pick, and shows the month one offer overtakes another.

Mortar for block and brick work from the unit count and the joint size, in bags of mix or in sand, cement and lime for a site batch.

Prices a manufactured home move by distance and section count, then adds permits, escorts, set and level, blocking, anchors and the utility disconnect.

Counts valence electrons, places the bonds and lone pairs, checks the octets and formal charges, and draws the structure for a single central atom.

Turns a rebuild cost into the full set of homeowners limits: Coverage A, then B, C and D as shares of it, with liability kept separate and the contents and loss-of-use figures tested.

Totals a nine or eighteen hole card: gross, net after a course handicap spread by stroke index, stableford points and the adjusted gross a round is posted with.

Scores the original 1977 Goldman index across its nine weighted criteria and reports the class, alongside what that class actually did in the cohort the index was derived on.

Free water deficit in hypernatraemia from total body water and the measured sodium, with the volume the usual 24-hour correction-rate limit allows and the rate that implies.

Cardiac output and cardiac index by the Fick principle, from oxygen consumption, haemoglobin and the arterial and mixed venous saturations.

How much epoxy a mould, river channel or flood coat takes, split into resin and hardener at any mix ratio by volume or by weight.

Multiplies out a(b + c) with every individual product written down, handles any number of letters, and factors the common term back out of an expression.

Prices a deck line by line: boards, framing, posts, footings, hardware, railing, stairs, labour, tax and fees, at the prices you enter.

Works out the half-your-age-plus-seven saying: the range it produces for one age, or whether two ages fall inside it. A folk rule with no research behind it, shown as one.

Works out the cost of equity three ways: CAPM, the dividend growth model, and a bond yield plus a premium, then shows the spread between them and what each implies for the share price.

Corrected or adjusted age for a baby born early, from the due date or the gestational age at birth, with the chronological and postmenstrual ages too.

How much compost to top-dress an area at a given depth, in bags, bulk yards and weight, plus the carbon-to-nitrogen ratio of a pile and what to add to bring it to target.

Coffee and water in grams for drip, pour over, press, AeroPress, moka, cold brew or espresso, including the water the wet grounds keep back from the cup.

Nominal age by the East Asian reckoning, where a baby is one at birth and everybody gains a year at Chinese New Year rather than on a birthday.

Splits a deposit into staggered certificates, shows what each rung is worth at maturity and gives a blended yield worked out as an internal rate of return.

Adds depreciation, fuel, insurance, servicing, tyres, tax and loan interest over a whole ownership period, then turns the total into a cost per year, per month and per mile.

Draws a box and whisker plot from your data, with the five number summary, the IQR, the Tukey fences and every outlier named.

Averages a list of durations, and averages times of day with the circular mean, so 23:00 and 01:00 come out as midnight rather than as noon.

Averages percentages the right way. Enter each percentage with the group size behind it and see the weighted answer next to the plain mean of the percentages.

One-way analysis of variance for up to six groups. Returns the sums of squares, degrees of freedom, mean squares, the F statistic and an exact p value.

Turns an oven temperature and time into air fryer settings, 25 degrees lower and a fifth less time, and gives the safe internal temperatures that actually decide doneness.

Works out the acreage of a lot from its length and width, its three sides, or its corner coordinates, and converts between acres, hectares, chains and rods.

Paste a run of annual figures and get the growth from each year to the next, the total change and the compound annual rate that connects the ends.

Converts a lens power between two vertex distances, such as a spectacle prescription to the corneal plane, meridian by meridian.

Solves ax + b = c, x/a + b = c and equations with x on both sides, writing out every step with both sides shown and the answer substituted back as a check.

Evaluate a triple integral over a rectangular box, a cylindrical wedge or a spherical shell, with the inner integrals shown and a numerical check alongside.

Works out time-lapse settings in either direction: clip length, card space and batteries from an interval, or the interval that fits an event into the clip you want.