Online Calculators & Tools

Estimates a home addition line by line: new floor area, foundation, tie-in to the existing house, bathrooms, heating, design fees and contingency.

Scores an English word in six gematria ciphers at once, or a Hebrew word by its standard letter values, and shows the letter-by-letter sum.

Work out the oil for a two-stroke mix at any ratio, check the ratio you actually poured, or find the fuel that matches a bottle of oil you already have.

Great circle distance between two sets of coordinates and the flying time at a cruising speed you choose, plus a ground allowance and the initial heading.

Fat-free mass index from weight, height and body fat, with the height-normalized version, in metric or imperial units.

Work out engine displacement from bore, stroke and cylinder count, in cc, litres and cubic inches, with an optional overbore for a block bored oversize.

Counts the drywall sheets a room needs and prices the job from your own sheet cost and hanging rate, with openings deducted and a waste allowance added.

Dilutes a stock to a target strength in percent, mg/mL or ppm, lays out a serial dilution series, and turns a label ratio such as 1:10 into real volumes.

Determinant of a square matrix from 2 x 2 up to 6 x 6, with every row operation, the pivots and the sign from the row swaps written out.

Totals a dental implant quote line by line, from the post and crown to extractions and grafting, then applies insurance and a payment plan.

Compares keeping the debts you have against clearing them with one consolidation loan, showing both monthly payments and both total interest figures.

Applies the Payne albumin correction to a total serum calcium result, in mg/dL or SI units, with the formula, its assumptions and its limits stated.

Models the interest-only draw period while a house is built, then the permanent mortgage payment the loan converts to at completion.

Standard deviation divided by the mean, as a percentage. Works from a list of numbers or from summary figures, and compares two sets side by side.

Convert a cat's age to human years using the published International Cat Care chart, and see the life stage the 2021 AAHA/AAFP guidelines place it in.

Adds up a year of home energy, driving, flights and diet using published EPA, EIA and peer-reviewed emission factors, each one named and dated in the result.

Projects what a vehicle will be worth using the declining balance model, with a steeper first year, and works the rate back from a real resale value.

Works out the calories burned on a run from your weight, distance and either the time or the pace, and reports the cost per mile and per kilometre.

Values a small business two ways, on a multiple of seller discretionary earnings and on a discounted cash flow, and shows each as a range rather than one figure.

Turns underbust and bust measurements into a band and cup size in US, UK and European labelling, with the sister sizes that hold the same cup volume.

BMI percentile for children and teens aged 2 to 20, read against the CDC 2000 BMI-for-age reference by sex and age in months, with the weight status category.

Estimates blood alcohol with the Widmark equation from drinks, body weight and time, reported as a wide range. It cannot tell anyone they are safe to drive.

Budget a window replacement job line by line: window units by frame material, installation labour, trim, disposal and permit, as a low to high range.

Converts wheel offset to backspacing and back, and compares two wheels to show how far the new one moves toward the fender or the suspension.

Turns a starting weight and a current weight into the percentage of body weight lost, with the five and ten percent marks and progress to a goal.

Divides waist by hip circumference and reads the result against the WHO 2008 cut-offs, in centimetres or inches, with the waist measurement checked too.

Turns a bed or lawn measurement into bags of topsoil and bulk cubic yards, compares the cost of both, and fills raised beds with a soil blend.

Liquid capacity of capsule, oval, cone bottom and rectangular tanks, full or part full, in gallons, litres and cubic feet from inside dimensions.

Convert square feet to linear feet, or back again, using the width of the boards or rolls you are buying, plus a waste allowance and a piece count.

Solves for speed, distance or time from the other two, in miles, kilometres, metres, feet, yards or nautical miles and five speed units.

Panels and system size needed to cover your monthly kWh, from panel wattage, peak sun hours and system losses, plus output and simple payback.

Suggests a ski length from height, weight, ability and the kind of ski, using the published retailer size charts, and shows every step of the adjustment.

Turns building measurements and a pitch into sloped roof area and squares, plus rafter length, ridge, eave and rake runs and the roof angle in degrees.

Works out how long a retirement balance lasts at a given withdrawal, or how much may be withdrawn for it to last a set number of years.

Works out the bags of salt a saltwater pool needs to reach its target salinity, and how much water to replace when the reading is too high.

Works out Pokemon type matchups from the eighteen type chart. Pick a single or dual typing for its weaknesses, or a move type for its damage multiplier.

Separates documented medical costs and lost income from a pain and suffering range built on a multiplier you choose. Not a case valuation.

Project your next period dates, the estimated ovulation day and the fertile window from your last period and your usual cycle length.

Find the percent increase or decrease between two values, apply a percent change to a number, or work back to the value a known change started from.

Convert powder in milligrams and bacteriostatic water in millilitres into a concentration, a draw volume and U-100 insulin syringe units.

Plan the soft drinks, mixers, bottled water, ice and cups for a party from your guest count, the hours and how many guests skip alcohol.

Enter any two of voltage, current, resistance and power and get the other two, with the formula used and unit prefixes from microamps up to kilovolts.

Estimates maximum heart rate from age using four named published equations, and shows how far apart they are instead of hiding behind one.

Finds the internal rate of return on an uneven series of cash flows, solved numerically, with the net present value at any discount rate alongside it.

Finds the inverse of a linear, rational, power, exponential or logarithmic function from its coefficients, with the swap and solve steps written out.

Solves linear, quadratic, absolute value and compound inequalities from their coefficients, in inequality and interval notation with the steps shown.

Build a line-by-line budget for a new house: living space, garage, site work, design fees, contingency and land, each shown with its own figure.

Work out your five training zones in beats per minute by the Karvonen heart rate reserve method, from your age and resting pulse.