Online Calculators & Tools

Counts the terms left to a degree from credits remaining and credits per term, and works the other way to find the load needed to finish on time.

FIRE stands for Financial Independence, Retire Early. Works out how many years of saving separate you from the point where investments cover your spending.

Works out the score you need on the final exam to reach a target course grade, from your current grade and the weight the syllabus gives the final.

Turns watts and hours into kilowatt hours and money. Cost an appliance per hour, day and year, or price a metered reading with standing charges.

Finds the eigenvalues and real eigenvectors of a 2 x 2 or 3 x 3 matrix by solving the characteristic polynomial exactly, complex pairs included.

Gives the domain and range of seven named function families in interval notation, with the asymptote, vertex or endpoint that produces the answer.

Dividend income from shares, price and yield, a year by year projection with reinvestment, and the payout ratio from earnings per share.

Solves first order linear, logistic and second order homogeneous differential equations exactly from numeric coefficients and initial conditions.

Counts the deck boards, screws, joists, beam, posts, footings and railing pieces a simple rectangular deck needs from its length and width.

Works out one billing cycle of card interest from the daily periodic rate, and shows how much of a single payment is swallowed by that interest.

Count the CMU blocks, mortar bags and courses for a block wall from its length and height, and the grout needed if the cores are filled.

Works out a commercial property loan payment over a long amortization, the balloon left when the shorter term matures, and the debt service coverage ratio.

Works out the calving date from a breeding date using a 283 day gestation, with a window either side, or works backwards from the calving date you want.

See the larger loan a cash-out refinance leaves behind: new balance, loan-to-value, the new payment and what the released cash costs over the term.

Prices carpet from the roll rather than the floor area: full width runs, which way to lay them, seam count, linear feet to order, padding and fitting.

Builds the full amortization schedule for a car loan, listing every payment with its interest, principal and remaining balance, or one line per year.

Cash down a car deal needs once sales tax, dealer fees and a trade-in that may still carry a loan are counted, or worked back from a target payment.

Works out the daily calorie deficit a weight loss deadline demands, the intake it leaves you, and whether that pace is a sensible one.

Works out body surface area in square metres from height and weight using the Mosteller, Du Bois, Haycock and Gehan and George formulas side by side.

Sorts bust, waist and hip measurements into one of six named body shape bands using the FFIT for Apparel rule set, with every threshold printed.

Bullet drop, wind drift, retained velocity and energy from muzzle velocity, G1 ballistic coefficient, zero range and sight height, with a drop table.

Resize an image or video while the proportions hold, read the ratio off a pixel size, or fit one ratio inside a frame and see the bars it leaves.

Turn an annuity balance into monthly income: for a fixed term, for a life you choose to plan to, or at a level that never spends the principal.

Estimate monthly and annual profit from a short-term rental, with platform and management fees, cleaning per stay, fixed costs and break-even occupancy.

Work out alcohol by volume from your original and final gravity readings, on both the simple homebrew formula and the more accurate alternate one.

Scores two sun signs against the traditional aspect and element tables and returns a percentage, the aspect name and both elements. Entertainment, not advice.

Volume of a sphere, a cone or a rectangular pyramid from its radius or base and height, converted to cubic feet, cubic metres, litres and gallons.

Find the current in amps from a voltage and either the watts or the ohms, for DC, single-phase AC with a power factor, or three-phase AC.

Turn a Unix epoch value into a readable date, or a date into a timestamp. Handles seconds and milliseconds, UTC and fifteen local time zones.

Solves a triangle from three known parts with the sine and cosine rules, returning the missing sides and angles, area, perimeter, circumradius and inradius.

Works back from the monthly payment you can afford to the travel trailer price it buys, after sales tax, dealer fees, cash down and a trade-in.

Work out how many tiles and boxes a floor or wall needs, with the grout joint, a waste allowance and the grout volume included.

All three placements from one set of birth details, worked out from the real solar and lunar positions and the sidereal time at the place you were born.

Floor area room by room in feet and inches, added into a house total, then turned into the number of flooring cartons you need to order.

Projects a systematic investment plan whose monthly contribution steps up by a set percentage every year, or finds the starting amount for a goal.

Gauss-Jordan reduction to reduced row echelon form with partial pivoting, for matrices from 2x2 to 6x8, reporting the rank and the pivot columns.

Turns a roof footprint into real sloped area with a pitch multiplier, then prices shingles, labour and tear-off by the square and by the bundle.

Projects how a reverse mortgage balance compounds against your home value, and turns an available principal limit into a tenure or term payment.

Simplify a ratio to its lowest terms, solve A : B = C : ? for the missing value, or split an amount into shares using any ratio.

Estimates what a puppy will weigh grown from its age, its weight today and the size group its breed finishes in, with a loose range around the answer.

Work out PTO hours earned each pay period, the balance on a given date after accrual and time taken, and what those hours are worth in days.

Turns cost and selling price into a profit margin and a markup, and works backwards to the price a target margin needs. Two views of the same profit.

Shows the 2009 Institute of Medicine weight gain range for your pre-pregnancy BMI and your current week, for one baby or twins.

Counts how many weeks and days along a pregnancy is on any date, from the last period or the due date, with the trimester and the time left.

Find how many gallons a rectangular, round or oval swimming pool holds, with shallow and deep end depths, plus the time and cost to fill it.

Divides one polynomial by another the long way and shows every subtraction, with the quotient, the remainder and a check that rebuilds the dividend.

Splits a pay period into regular, time-and-a-half and double-time hours from your hourly rate, and totals the pay earned in each band.

Adds up what you own and subtracts what you owe, with a line-by-line breakdown of assets, debts and the change since your last snapshot.