Online Calculators & Tools

Checks a bedroom or basement window against the IRC egress minimums for net clear area, width, height and sill, and sizes the window well.

Read a heart rate off an ECG strip: the 300 and 1500 box rules, the six-second complex count for irregular rhythms, or a measured RR interval.

Score a game of dominoes: points for the open ends in All Fives, Threes and Fives and Threes, the pips left in a hand, and the score at the end of a hand.

Map a bitch's heat cycle from the first day of bleeding: proestrus, standing heat, dioestrus and the next heats, or work out her own interval from two dates.

Turn a decimal into a percentage or a percentage back into a decimal, with the working shown and the decimal point moved exactly rather than multiplied.

Days sales in inventory from the inventory balance and cost of goods sold, with the inventory turnover ratio and the stock level a target DSI would need.

Work out a fifth edition D&D character's Armor Class from armor, Dexterity, a shield and magic bonuses, with the Stealth and Strength penalties spelled out.

Pack a list of different piece lengths onto as few sticks of stock as possible, with the kerf counted, the cut pattern drawn and the waste broken down.

Grows a balance at compound interest while regular withdrawals come out of it, and shows the closing balance year by year.

Midpoint composite chart for two births: Sun through Pluto, the node, both composite ascendants and the aspects inside it, plus the Davison chart.

Estimate how long a clean takes from a production rate or a room list, with the labour hours, the time on site and the crew size a window needs.

How many Christmas lights a tree takes, either from the 100-per-foot rule or from the real shape of the tree, plus strands to buy and the power they draw.

Sizes a coop and run for a flock: floor area, run area, perch length, nest boxes and ventilation, or how many birds a coop you already have will hold.

Work out volume, surface or linear charge density from a charge and a volume, area or length, in any common unit, with the elementary charge count.

Blade span for a room from the published size guideline, with the wall clearance that caps it and the downrod length for your ceiling height.

Turns a cat mating date into a kitten due date, with the usual 63 to 67 day window, the scan and x-ray dates, and how far along she is today.

Net cash flow from inflows and outflows, with the closing bank balance and runway, plus a full cash flow statement by the indirect method.

Work out the area, weight, tonnage and tack strip for a carpet tear-out, then price it with your own quoted labour, tipping and haul-away rates.

Estimates the calories burned in a session from your average heart rate, sex, age and weight, using the published Keytel equations rather than a MET table.

Works out a league bowling handicap from an average, using the basis score and percentage your league sets, with the series total beside it.

Average rate of change of a function over an interval, with f(a), f(b), the working, the secant line and the mean value theorem point for a polynomial.

Series R-L-C values for one sinusoidal supply: both reactances, impedance, current, phase angle, power factor, the three powers and resonance.

Work out a year-to-date return both ways: the simple percentage change, and the money-weighted figure that takes your own contributions back out of it.

Yahrzeit dates from a Gregorian or Hebrew date of death, with the rules for 30 Cheshvan, 30 Kislev, Adar in a leap year and the sunset boundary.

Lay out frame-and-panel wainscoting so the panels come out equal across a wall, with stile spacing, layout marks and the cap, rail and base linear feet.

Work out true shooting percentage from points, field goal attempts and free throw attempts, with effective field goal percentage beside it for comparison.

Work out an owner-operator's cost per mile from fixed and variable costs, with the deadhead share that makes the loaded-mile rate different from the total-mile rate.

Total the cost of a laser tattoo removal course from your clinic's own rate, across the session range you were quoted, and against what the tattoo cost.

Work out the most you can put into an owner-only 401(k): the employee deferral plus the employer share, on the right base for Schedule C profit or a W-2 wage.

Simpson's D, 1 - D and 1 / D from species counts, with the proportion forms, Shannon beside them, and the per-species working set out in full.

Reduce a product or quotient of powers to a single term, applying the product, quotient, power of a power, negative and zero exponent laws with the arithmetic shown.

The geometrically correct field of view for a sim racing rig, worked out from your screen size and how far your eyes sit from the glass, for one screen or for triples.

Total capacitance of up to four capacitors in series or parallel, with the voltage across each one in a series chain and the charge and energy stored.

Usable ZFS pool capacity for RAID-Z1, Z2, Z3 and mirrors, with the parity cost, the raidz padding overhead, the 1/32 reserve and TB against TiB.

People per square kilometre and per square mile from a population and an area, in either direction, with physiological density when usable land is known.

Plan effort value training: battles to a target EV with Pokerus, items and vitamins, the 510 and 252 caps, and what a spread is worth in stat points.

Work the PSI or PORT score for community-acquired pneumonia: twenty weighted items, the risk class I to V and the cohort mortality behind it.

Turn a radar reading into what the hitter actually faces: effective velocity from the release point, travel time to contact and the reaction window.

Present value of an endless payment stream from PV = C / r, the growing form C / (r - g), and the reverse solves for the payment or the implied return.

Score a women's indoor pentathlon on the World Athletics tables: 60 m hurdles, high jump, shot put, long jump and 800 m, event by event.

Predicted peak flow from height, age and sex using the Nunn and Gregg 1989 equations, plus the percentage of personal best and the green, yellow and red bands.

Add up a PC build from your own part prices with tax, shipping and rebates, see where the money goes, and what the machine costs a month to actually own.

Runs a paired-samples t-test on the raw before and after columns, returning the differences, t, both p-values, a confidence interval and the effect size.

See what rolling negative equity into a new car loan really costs a month, and which month the new loan finally drops below what the car is worth.

Open channel flow by Manning's equation for rectangular, trapezoidal, triangular and part-full circular sections, with normal depth solved iteratively.

Solve a linear program two ways: two variables with the feasible region drawn and the optimum at a vertex, or the simplex tableau with every pivot shown.

Prices an insulation job from the area and the R-value you want, and lines up nine materials at the same R so depth and cost can be compared properly.

Gravitational force between two masses, surface gravity and escape velocity from a mass and radius, and the speed and period of a circular orbit.