Online Calculators & Tools

Scores a pairing of two Chinese zodiac animals using the traditional harmonies, clashes and harms between the twelve branches, plus their fixed elements.

Works out how many battens fit a wall, the real gap between them once they divide evenly, the linear feet of lumber and the boards to buy.

Turns a battery capacity in mAh and a device load in mA into a runtime, with a derating factor, and works out the life of a duty cycled device that sleeps between wakes.

Works out the loan to value ratio on a car loan, the balance measured against what the vehicle is worth, and shows the negative equity and gap that sit above it.

Divides AST by ALT to give the De Ritis ratio, with the inverse, the band the figure falls in and each enzyme against your own laboratory's upper limit.

Finds the length of a circular arc from the radius and central angle, with the chord, the sector area and the segment area alongside it.

Tank volume, surface area, filter turnover and the ammonia and nitrate a stocking plan produces, worked out from the fish you actually intend to keep.

Converts a nominal interest rate and a compounding frequency into the annual percentage yield, runs the conversion backwards, and compares two accounts side by side.

Projects yearly mileage from two dated odometer readings, and shows whether a lease allowance will be blown and what the excess miles would cost.

Reduces the digits of a birth date to a single figure and shows the repeating sequence it makes, or breaks down a number you keep noticing.

Adds a column of figures and prints a tape with the running total on every line, plus the added and subtracted subtotals and an optional percentage.

Wet bulb temperature from air temperature and relative humidity using the Stull approximation, with the reverse reading for a sling psychrometer.

Works out watt hours from a power draw and a running time, from a battery's mAh or Ah rating and its voltage, or backwards into a runtime.

Roasting and thawing times for a turkey, taken from the published USDA chart, plus the hour to put the bird in the oven if you know when you want to carve.

Prices a tiling job from your own rates: tile with waste, setting materials, backer board, labour and tear-out, with a cost per square foot installed.

Work out the profit on a share trade from the shares, both prices and the commission on each side, with the break-even price and the return per year.

Turns a script or a word count into a delivery time at a named speaking rate, and works backwards to the number of words that fit a time slot.

Board length from rider weight, ability and the kind of riding, plus the waist width your boot size needs, with the sizing rule stated in the answer.

Works out the reactions, the shear force and the bending moment along a simply supported beam or a cantilever carrying a point load, a uniform load, or both.

Estimates the calories a ruck costs using the Pandolf load carriage equation, which takes the weight of the pack, the grade and the terrain, not just the pace.

Works RSA through on small primes: the key pair, the encryption and decryption of a number, and the extended Euclid step that produces the private exponent.

Portions a raw diet by percentage of body weight and splits the daily weight into muscle meat, raw edible bone, liver and other organ.

Works out how much shock a pool needs to reach a free chlorine level, or to reach breakpoint from a combined chlorine reading, at the strength you pick.

How much water a run of pipe holds, looked up from the nominal size and wall schedule, plus the velocity and fill time at a given flow rate.

Turns a strong acid or base concentration into pH and pOH, works back from a measured pH, and gives the pH of a diluted solution.

Compares two values against their mean, which makes the answer the same whichever way round you enter them, and also gives percent error against a known value.

Add up a drawer of cash by entering how many of each note and coin you have, and see how many bank rolls the coins make and what is left loose.

Works out the molar mass of any chemical formula from a built-in periodic table, handling nested brackets, hydrates and the percentage each element contributes.

Estimates MCAT section scores and the 472 to 528 total from practice raw scores, and works out exactly what the last section needs for a target total.

Sizes the series resistor for an LED from supply voltage, forward voltage and forward current, in E12 and E24 values, for series and parallel strings.

A fixed table of twelve standard Laplace transforms with your own constants in them, plus polynomials in t by linearity. Symbolic algebra is refused.

Prices a laminate floor installed rather than just the planks: cartons, underlayment, labour, old floor removal and trim, with a DIY comparison.

How much insulation an area needs for its climate zone: the R-value target, the depth of loose fill to reach it, and the batt count for a framed wall.

Project what a house will be worth at an appreciation rate you choose, or find the yearly rate a home you already own has grown at, with or without inflation.

Curves a whole class of raw scores three ways: the square root curve, the highest score curve, and a linear rescale to a target mean and spread.

Turns a dextrose infusion that has already been prescribed into mg/kg/min, or an ordered glucose infusion rate into a pump rate in mL per hour.

Adds the three Glasgow Coma Scale components into a total and writes the E, V and M notation, with a not-testable option on every component.

Finds the geometric mean of a list of positive numbers, plain or weighted, and shows it beside the arithmetic and harmonic means for comparison.

Works out the dimensional weight of a parcel from its measurements and tells you which weight the carrier actually bills, using the divisors carriers publish.

Works out the hit point maximum for a Dungeons & Dragons fifth edition character from class, level and Constitution, on the average or a rolled total.

Customer lifetime value under three named models: subscription churn, a fixed horizon, and the retail order formula, each with the LTV to CAC ratio and payback.

Counts a cribbage hand or crib from the four cards and the starter, scoring fifteens, pairs, runs, the flush and his nobs under the right rule.

Find the carburetor CFM an engine needs from its displacement, peak rpm and volumetric efficiency, or the rpm a carburetor you already have can feed.

Costs a lease and a car loan over the same number of months, counting the equity left in a bought car against the payments and fees on a lease.

Counts the bricks and bags of mortar for a wall from its size and the brick's own face, with nine standard brick sizes and a custom option.

Expands (a x + b) raised to a whole power using the binomial theorem, term by term, with the Pascal row and the working behind each coefficient shown.

Adds, subtracts, multiplies and divides two binary numbers directly in binary, showing the carries, borrows or partial products, plus AND, OR, XOR, NOT and both bit shifts.

Converts basis points to percentages and back, measures the gap between two rates in basis points, and prices a fee quoted in bps on a balance.