Online Calculators & Tools

Elo expected score, rating change after a game or an event at any K factor, and the performance rating a tournament score works out to.

Prices a cake from ingredients, hours at your own rate, overhead and margin, and works out how many servings a round, square or tiered pan actually cuts.

Sizes a bridge loan against the equity in the home you are selling, then shows the interest-only payment, the balloon, the fees and the cost of carrying both homes.

Break-even units and revenue from fixed costs, price and variable cost, with the contribution margin, the margin of safety and the volume a target profit needs.

Which ABO and Rh blood types a child can have, from the parents' types, plus exact Mendelian percentages when the parents' genotypes are known.

Average atomic mass from up to six isotope masses and their natural abundances, with each isotope's contribution shown and the abundances held to a total of 100 percent.

Reads a dimension off a drawing at an architect's or engineer's scale, gives the size to draw in inch fractions, and picks the largest scale that fits the sheet.

Estimates how long until blood alcohol returns to zero after drinking, from drinks, body weight and time elapsed, with the range around that estimate.

Work out how many lands a Magic deck needs. Hypergeometric odds for the opening hand, for hitting every land drop through a given turn, and after a London mulligan.

Seed for a new lawn or an overseeding, from the area and the grass, with the published rate per species editable and the starter fertiliser alongside.

Run both phases of a deferred annuity: what a premium and its contributions grow to, and the fixed-term income that pot then buys.

Planetary lines on a world map from a birth moment: the MC and IC meridians, the rising and setting curves, and which of them pass near a place you name.

Prices an asphalt driveway line by line: hot mix, aggregate base, tear-out, excavation, labour, tack coat, edging and sealcoating, at your own rates.

Work out what a tire change does to the final drive, the rpm and the speedometer, and which axle ratio puts the original gearing back.

Work out the tablecloth size for a rectangular, round or oval table from the drop you want, with the nearest stock size and how many the table seats.

Turns a list of numbers into a stem and leaf plot with the leaf unit stated and a key, splits crowded stems, and draws two data sets back to back.

Tile for a shower rather than a flat floor: three walls, the curb on three faces, every niche, the pan, and the mortar bed a sloped pan needs.

Design daily flow from bedrooms or occupants, the tank capacity the detention rule needs, and drainfield area from a percolation rate you measured.

Payment on an SBA 7(a) loan, with the guaranty fee from the statutory schedule, a base rate plus spread you set yourself, and the 10 and 25 year term caps.

Reynolds number for a pipe, a duct, a flat plate or a body in a stream, with water and air properties from temperature and the laminar or turbulent verdict.

Builds the whole frequency table from raw values or from counts you already have: frequency, relative frequency, percent and both cumulative columns.

Estimate a digital PSAT section and total score from raw correct answers, and work out the NMSC Selection Index exactly from the section scores you already hold.

Work out propane burn rate from an appliance BTU rating, how many days a tank has left under the 80 percent fill rule, and the cost at your own price per gallon.

Integer arithmetic, shifts and rotates inside an 8, 16, 32 or 64 bit word, with the carry, overflow, zero and sign flags and every result in four bases.

Work out pixels per inch from a screen resolution and diagonal, run it backwards to a screen size, and find the dot pitch and the distance pixels blend at.

Price a swimming pool build from its own dimensions: interior surface, coping, decking, fencing and excavation quantities, each multiplied by a rate you enter.

Doses for pH, total alkalinity, calcium hardness and cyanuric acid by pool volume, worked from the chemistry rather than a printed table, with the usual ranges.

Works out a Pokemon's six stats from base stats, IVs, EVs, level and nature, using the exact integer formula the games have used since generation 3.

Adds up a pet sitting booking from your own rates: visits per day, visit length, extra pets, overnight stays, holiday surcharges and mileage.

Works out the North Node and the South Node from a birth date and time, with the sign, the exact degree, the dates the axis changes sign, and your nodal returns.

Projects a mutual fund with the expense ratio and any sales load taken out, and shows what those fees cost against the same fund charging nothing.

Monthly payment on a home loan with principal, interest, tax, insurance, HOA and PMI, showing the month the mortgage insurance falls off and what it costs until then.

Multiplies whole numbers of up to fifty digits and shows the working: a partial product for every digit, the column they add up in, and every carry.

Cartons of laminate plus underlayment rolls, the expansion gap, the row layout with the stagger and the last row width, and the transition strips a floating floor needs.

Converts a height between feet and inches, centimetres and metres, and places a child or teenager from 2 to 20 on the CDC stature-for-age percentile chart.

Work out the fall a gutter run needs at a chosen slope, whether the fascia board can hide that drop, and where the downspouts go on a long run.

Tension a string pulls at a given gauge, scale length and tuning, and the reverse: the plain steel gauge a target tension needs at that pitch.

Convert gold karat to fineness and percent, work out what to add to reach a target karat, and price scrap gold from a spot rate you enter yourself.

Head loss and pressure drop in a pipe run by Darcy-Weisbach with Colebrook, shown next to Hazen-Williams for water so the gap between the two methods is visible.

Exact hypergeometric p value for a 2x2 contingency table, one tailed and two tailed, with the odds ratio and the whole distribution the p value is read from.

Costs an exterior paint job from the house measurements: walls, gables and openings, body and trim paint, primer, labour and prep, with the gallons to buy.

How many gallons a house exterior needs: wall area from the perimeter and gables, openings off, and body, soffit, trim and primer counted separately.

Expand a logarithm into a sum of simple terms with the product, quotient and power rules shown step by step, and condense a sum of logarithms back into one.

Turns decimal hours from a timesheet into hours and minutes, and back again, with the nearest minute, tenth and quarter hour payroll uses.

Adjusted cost basis from reinvested dividends, return of capital, wash sales and splits, plus the gain on a sale under FIFO, LIFO or a chosen lot.

Works out what a pour weighs from its volume or from slab dimensions, fresh and after curing, and the dead load a slab puts on the floor below.

Isentropic flow relations for a perfect gas: stagnation ratios at any Mach number, choked mass flow through a nozzle, and the Mach number behind a ratio.

Scores the five Bishop criteria - dilation, effacement, station, consistency and position - with the modifiers, and shows the band the total falls in.