Online Calculators & Tools

Turns a cutting speed and a chip load into spindle RPM and feed rate for milling or turning, with radial chip thinning and the metal removal rate.

Encounter difficulty for D&D 5e from the 2014 DMG tables: party XP thresholds, the encounter multiplier for monster count, and the adventuring day budget.

Work out click-through rate from clicks and impressions, find the clicks a target CTR needs, and test whether two versions really differ.

Turns a length and a girth measurement into the nominal width printed on a condom box, plus the length range to look for and how the figure is worked out.

Price a concrete driveway as a full takeoff: thickness for the traffic, concrete to the quarter yard, gravel base in tons, mesh or rebar, and the control joint layout.

Work out what driving to work costs over a full year in fuel, wear and parking, and set that total against a transit pass or a carpool share.

Turn a neck, sleeve, chest or bust measurement into a shirt size, a jacket size and a letter size, with the UK and European numbers alongside.

Estimates a child's adult height from both parents using the mid-parental method, and gives the 10 cm range either side that the estimate is really good to.

Counts the parts a chain link fence takes and prices them: line and terminal posts, top rail, fabric rolls, tension bars, bands, caps, ties and concrete.

Set your monthly take-home pay against every expense category, see the surplus or shortfall, and compare the result with the 50/30/20 split.

Finds the sign and degree of mean Black Moon Lilith, the apogee of the Moon's orbit, from a birth date and time, with the ingress dates either side.

Splits a bill that does not divide evenly: each person pays for what they ordered with tax and tip shared in proportion, or the total is split by uneven shares.

Works out arrow FOC from a measured balance point or from the component weights, and gives the balance point, total arrow weight and grains per pound.

How much gravel, sand or planted substrate a tank needs, in pounds and kilograms, from the footprint, the depth and the bulk density of the material.

Apply a named, published spousal support guideline to two incomes and see every step of it, or run all five side by side to see how far apart they land.

Works out 0-60 acceleration three ways: average g and distance from a time, the time from a distance and a speed, and an estimate from weight and horsepower.

Works out which zodiac sign Venus was in from a birth date and time, with the exact degree, whether it was retrograde and how far it stood from the Sun.

Commercial truck finance with a balloon residual, terms out to 120 months, the payment expressed per mile, and the first year write-off on the purchase.

Solves any triangle from three measurements, SSS, SAS, ASA, AAS or SSA, returning every side, every angle, the area, the heights and both radii.

Approximates a definite integral with the trapezoidal rule, over a polynomial, a standard integrand or a table of measured points, with the error bound.

Adds up a tow the way the invoice does: hook-up fee, billable miles, after-hours and winch-out surcharges, storage and tax, from the rates you were quoted.

Gives the tangent line to a curve at a point, the normal line through the same point, and the linear approximation with the error it makes nearby.

Finds the rule behind a list of numbers, arithmetic, geometric, quadratic or Fibonacci style, then gives the nth term, the sum and the terms that come next.

Turns an efficiency rating into money: annual cooling cost at your own electricity rate, the saving from a higher rating, the payback on the price difference.

Works out engine RPM from road speed, tire size, gear ratio and final drive, and runs the same chain backwards for road speed or the axle ratio you need.

Works out the 500 m split, the finish time and the wattage for an erg piece, converting freely between any two of distance, time, split and power.

Estimates resting metabolic rate from lean body mass with the Katch-McArdle and Cunningham equations, so body composition drives the answer rather than height and age.

Turns a word count or a block of pasted text into a reading time at the speed you pick, and works backwards from a slot to the words that fit it.

Turns output and hours into productivity per hour and per worker-hour, measures how much of the available time was productive, and compares two periods.

Works out the pointwise mutual information of two events from their joint and marginal probabilities, or from raw counts and a corpus size, with PPMI and normalised PMI alongside.

Differentiates a polynomial in x, y and z with respect to any one of them, and returns the gradient, the second partials and the value of each partial at a point.

Picks the head size for a room, checks how many heads one outdoor unit will carry, and shows the short cycling penalty when an inverter head is too big.

Writes a 2x2 or 3x3 matrix as P D P inverse, with the eigenvalues, the eigenvectors that form P, the inverse and the check that the product returns A.

Factorises a 2x2, 3x3 or 4x4 matrix into L and U by Doolittle with partial pivoting, returning P, the permutation sign and the determinant.

Prices a land survey from your own per-acre or hourly rate, adjusted for survey type and terrain, with research, monuments, travel and plat recording as separate lines.

Shows how an indexed universal life policy turns an index move into a credited rate through participation, spread, cap and floor, and what the charges take.

Sums geometric, p-series, telescoping and arithmetico-geometric series, names the convergence test that settles each one, and shows a partial sum beside it.

Estimates what it would cost to rebuild your house from a local per square foot rate, and measures the dwelling coverage on your policy against it.

Works out what a renovation loan lends against the after-renovation value, and weighs the equity a project creates against the interest borrowing for it costs.

Converts a birth date to the Hebrew calendar and finds the Gregorian date the Hebrew birthday falls on in any year, with bar and bat mitzvah dates.

Builds an itemised cost for a garage from its size and your own rates: slab, framing, siding, roof, doors and wiring, attached or detached.

Costs a recipe per serving from ingredient quantities and pack prices, gives the food cost percentage against a menu price, and the price a target food cost needs.

Adds up a fantasy football stat line under your own league settings, with PPR, half PPR and standard presets and every point value as an editable field.

Evaluates a^(bx+c)+d at a point, solves it for x, turns a growth rate into a doubling time and half life, and fits a curve through two readings.

Works out the drop from a level line over any distance, how far away your horizon is, and how much of a distant object the curve hides from view.

Splits a fill between the E85 pump and the gasoline pump to hit a target ethanol content, and works out what a partial fill actually left in the tank.

Works out the vertical jump you need to touch the rim, hang on it or dunk with the ball clearing, and runs it backwards from a vertical you already have.

Works out joint compound by the pound and by the bucket for a board area, split across the tape, fill and finish coats, with the tape and screws to match.