Online Calculators & Tools

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.

A recast re-amortizes your loan after a lump sum and lowers the payment while keeping the original payoff date. See the new payment and interest saved.

Applies a lender's two qualifying ratios, housing and total debt, to show the largest loan a program allows and whether a specific loan would pass them.

Molarity from a weighed mass or from moles and a volume, plus the grams to weigh out for a target concentration and the stock volume for a dilution.

Monthly payment and interest on a manufactured or mobile home loan, with lot rent in the monthly cost and a chattel loan set against a mortgage.

Estimates mean arterial pressure from a cuff blood pressure reading using MAP = diastolic + (systolic - diastolic) / 3, with pulse pressure alongside.

Turn a target marathon or half marathon time into a full table of cumulative splits, with an optional negative split, plus a Riegel time prediction.

Evaluates limits of rational functions exactly: at a point by dividing out (x - a), and at infinity by comparing degrees and leading coefficients.

Split revenue into gross, operating and net profit using cost of goods sold, operating costs and tax, or work the same margins up from unit price and cost.

Works out frames per second from a frame count and a capture time, turns a frame rate into a frame time in milliseconds, and sets it against a refresh rate.

Adds, subtracts, multiplies and divides lengths written in feet and inches, giving the answer back in feet and inches to the nearest sixteenth.

Factors a whole number into every divisor and its prime powers, or factors a one-variable polynomial up to degree 4 into linear factors.

See the down payment, closing costs and total cash a home purchase needs, or turn the savings you already have into the price they would cover.

Estimates the theobromine and caffeine dose a dog took from chocolate in mg per kg of body weight, against the thresholds published in the Merck Veterinary Manual.

Cylinder volume from diameter and height, plus the contents of a part-full tank standing upright or lying on its side, in litres and gallons.

Combines the GPA and credits already on your transcript with a new term of courses, and finds the GPA a term needs to reach a target overall.

Turns an area and depth into tons of crushed stone to order, with coverage per ton, truck loads and cost, or works out how far a delivered tonnage spreads.

Shows the utilization ratio on each credit card and across all of them together, plus how much to pay down to reach a target percentage.

Estimates creatinine clearance with the Cockcroft-Gault equation from age, sex, weight and serum creatinine, reported in mL/min rather than as an eGFR.

Work out advertising cost per mille from spend and impressions, or go the other way to find the cost or the impressions a CPM rate buys.

Finds the balance you would need invested today to reach a retirement target on growth alone, with no further contributions, and compares it to what you hold.