Online Calculators & Tools

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.

Solves absolute value equations in one variable, splits each one into its two cases and checks every candidate, so an extraneous root is named rather than handed back as an answer.

Works the 457(b) rules a 401(k) does not share: the three-year special catch-up, and taking money out with no 10% penalty once you have left the employer.

Finds where a line or parabola crosses each axis, from standard form, slope-intercept form, two points or a quadratic, with exact fractions.

Ramp length, run, angle and landings for a wheelchair ramp, measured against the ADA 1:12 maximum slope, or the slope you get from the space you have.

Adds up a wedding from your own quotes, per-guest and flat, with each line's share of the total, an optional contingency and a check against your budget.

Adds up a tree removal quote from your own rates: price per foot of height, an access surcharge, stump grinding, hauling, permits and tax.

Computes the z test statistic for a mean with a known sigma, for one proportion against a claimed value, and for two proportions compared.

Net internal volume of a subwoofer enclosure from its outside dimensions, the sealed alignment it lands on, and the port length for a chosen tuning.

Works out the interest a student loan builds up in school and grace, what capitalises onto the balance, and how a single payment splits.

Adds up the five RMR89 parameter ratings and the orientation adjustment, then returns the rock mass class, stand-up time and shear strength band.

Works out the Robux you keep after the 30% Roblox marketplace fee, what Roblox takes, and the price to list an item at to hit a target payout.

Turns an inside circumference or diameter into a US, UK, EU/ISO and Japanese ring size, with the sizes either side, and converts between the four systems.

Shows the rent your income supports under the 30 percent threshold and under a landlord's 3x income rule, and checks a listing you have already found.

Scales recipe ingredients to any number of servings with measurable fractions and spoon breakdowns, and converts a recipe between pan sizes.

Simplifies one polynomial over another, cancels the common factor, and lists the values the variable may not take, including the ones the cancelling hides.

Backing yardage for a quilt top: how many widths of fabric to join, which way to run the seams, and how much to buy at the next eighth of a yard.

Corrects a measured QT interval to a rate of 60 beats a minute by the Bazett, Fridericia, Framingham and Hodges formulas, with the published cut points.

Solves a : b = c : d for a missing term in any of the four slots, checks whether two ratios really are in proportion, and works out inverse proportions.

Elasticity from a before and after price and quantity, by the midpoint method or from the starting values, with the revenue either side of the change.

Poisson probabilities from a mean or from a rate and an interval: exactly k events, at most k, at least k, or anywhere in a range of counts.

Takes the bookmaker margin out of a market of two to eight outcomes and returns the fair probability and price for each, by three published methods.

Works a missing side or angle through the sine rule line by line, and prints both triangles when the ambiguous case leaves two of them standing.

Estimates a value between two known data points, solves the same line backwards for x, interpolates inside a table of points and does bilinear interpolation.

Estimates the 10-year risk of a first heart attack or stroke with the American Heart Association PREVENT equations, for adults aged 30 to 79 with no known heart disease.

Costs a hard money loan as one is actually written: origination points, interest-only payments, a minimum interest guarantee and a balloon at the end.

FIB-4 liver fibrosis index from age, AST, ALT and platelet count, with the published cut-offs and the APRI index alongside it.

Fractional excretion of sodium from a matched serum and urine pair, using the published Espinel formula, with the urea version and the cut-offs that go with each.

Damage per second from hit damage, attack rate, crit chance and multiplier, with time to kill and a sustained figure that counts the reload.

Divides one decimal by another and shows the working: the decimal point shift that makes the divisor whole, then the long division line by line.

Estimates what an accident took off a car's resale value, using the 17c formula with its damage and mileage multipliers or a before-and-after comparison.

Counts the calendar days and the working days left until a deadline, and works the other way to find the date a set number of working days out.

Prices a set of D&D 5e ability scores against the 27 point budget, applies species or background bonuses, and gives every final modifier.

Static compression ratio from bore, stroke, chamber volume, gasket, deck clearance and piston dish, plus the dynamic ratio from intake valve closing.