Free Calculators.
Built on MetaModel.

Length change of a steel, aluminum, copper or stainless member over a temperature change, and the stress if it is restrained.

Board feet and lumber cost for two sizes of stock — thickness, width, length and piece count to total board feet at your price per board foot.

A fixed-rate loan with a full year-by-year amortization table — opening balance, interest, principal, and closing balance per year.

Your monthly debt as a share of gross monthly income, banded against standard lending cutoffs.

Gear or pulley ratio from tooth counts or diameters, with the output speed and torque for a given input rpm, torque and efficiency.

Units and revenue needed to break even, the contribution margin per unit, and your margin of safety at an expected sales volume.

Profit, ROI and the 70%-rule maximum offer for a flip — purchase, rehab, holding and selling costs against the after-repair value.

Total closing costs and cash to close on a home purchase — origination, title, appraisal, inspection, prepaid taxes and transfer tax plus the down payment.

The hourly rate a freelancer or consultant must charge — from target income, overhead, billable hours and time off — checked against a market rate.

Hydraulic horsepower, brake horsepower and motor input kW for a pump from flow, head, specific gravity and efficiencies.

A step-by-step mortgage wizard: enter loan details, then taxes & insurance, then see your monthly PITI payment broken down.

Series and parallel totals for any list of resistors — add or remove resistors and both equivalents update live.

Working stress and factor of safety against yield for a loaded member, with a pass/warn/fail band and the allowable load for a target factor.

Enter a list of numbers — count, sum, mean, min, max, range, sample variance and standard deviation.

Friction loss for water in a pipe — velocity, Reynolds number, Swamee–Jain friction factor, Darcy–Weisbach head loss in feet and psi.

Resistance, power and conductance from a voltage and a current — V = I·R and P = V·I, solved for a DC circuit.

Open-belt length for two pulleys at a centre distance, the wrap angle on the small pulley, and the speed ratio.

Cooling and heating BTU/h for a room and the AC size in tons — from floor area, ceiling height, climate, sun exposure and occupants.

NEC copper ampacity for AWG 14–2 at 60/75/90 °C, plus the voltage drop and percent drop over a run at your load current.

Gallons in a horizontal or vertical cylindrical tank — total capacity, the liquid at a measured level, and percent full.

Boxes of flooring to buy and what they cost — room size plus waste, rounded up to whole boxes at your price per square foot.

Sheet-metal bend allowance, bend deduction and flat-pattern length from thickness, inside radius, bend angle and two flange lengths.

Posts, rails, pickets and concrete bags for a wood fence — add each run of fence, set post spacing and gates, and get the material cost.

Monthly payment for a car loan — price, down payment, trade-in, and sales tax to the amount financed.

Margin % and markup % from a cost and price — and the reverse: the price that hits a target margin on a given cost.

Concrete for a slab — cubic feet, cubic yards with a waste allowance, and 60 lb bag count from length, width and thickness.

Three ratio tools: solve a : b = c : x for x, split a total in a given ratio, and simplify a ratio to lowest terms.

Add, subtract, multiply or divide two fractions — the reduced fraction, the mixed number and the decimal.

Shingle bundles for a gable roof — footprint and pitch to sloped area, squares, and bundles with waste.

Convert length (in, ft, yd, mi, mm, cm, m, km), weight (oz, lb, g, kg) and temperature (°F, °C, K) in one place.

Rental property returns — cap rate from NOI and price, cash-on-cash from cash flow and down payment.

Sheets of drywall for a room — walls (and optional ceiling) to total area and 4×8 sheets with waste.

Private mortgage insurance from your down payment — loan-to-value, down payment percent, and the monthly PMI premium.

Infusion drip rate in drops per minute (gtt/min) from the fluid volume, the tubing drop factor and the infusion time.

How many months it takes for the monthly savings from refinancing to recoup the closing costs.

Monthly payment, total paid, and total interest for a fixed-rate loan.

How much mulch or gravel a bed needs — length, width and depth to cubic feet, cubic yards, and 2-cu-ft bags.

Inches of attic insulation to add, packages to buy and the cost — from your area, current R-value, climate zone and insulation type.

From two legs, or the hypotenuse and one leg: the third side, both angles in degrees, area and perimeter.

Solve ax² + bx + c = 0 — the discriminant, both roots (real or complex) and the vertex of the parabola.

How much paint to buy for a room — from wall dimensions, doors, windows and number of coats.

Deflection, bending moment and stress for a simply supported or cantilever beam under a point or uniform load — rectangular or round section, with an L/360 check.

Monthly cash flow, NOI and cash-on-cash return for a rental — rent, vacancy and an editable list of expenses tagged operating or financing.

Seller and buyer shares of the annual property tax at closing, and who credits whom — from the closing date on a 365-day basis.

Output voltage of a two-resistor divider, plus the loop current and the power dissipated in each resistor.

Tightening torque and clamp load for UNC ¼–1 in and M6–M20 bolts by grade or class, dry or lubricated — T = K·F·d.

Risers, treads, actual riser height, total run and stringer length from the total rise — with a code check on riser and tread size.

Months of runway from cash on hand, monthly burn and growing revenue — with a month-by-month cash balance table and the month the money runs out.

Compression-spring rate from wire size, coil diameter and active coils, plus the load at a deflection, spring index, Wahl factor and shear stress.

Total return, ROI, and annualized growth rate (CAGR) from an initial investment, its final value, and the holding period.

Grams of flour, water, salt and yeast for any number of pizzas from the ball weight and hydration, by baker's percentages.

Your estimated one-rep max from a set of reps at a weight (Epley, Brzycki, Lombardi) and the training loads at 95% down to 70%.

Grams of coffee for your water (drip, pour-over, French press, espresso, cold brew) — and how much water a dose of coffee needs.

Area and perimeter of a rectangle, triangle, circle, trapezoid or ellipse from its dimensions — pick the shape, enter the sizes.

Grams and ounces for a number of cups of flour, sugar, butter, honey, rice, oats or cocoa — and cups back from grams.

Scaled ingredient quantities for any number of servings — enter the recipe once, change the servings, every line updates.

Pace per mile and per km and your speed from a race distance and finish time — and the finish time a target pace gives you.

Daily grams of protein, carbs and fat from your calorie target and a goal preset (balanced, high-protein, low-carb, endurance, keto).

Your ideal body weight by the Devine, Robinson, Miller and Hamwi formulas, plus the healthy-BMI weight range for your height.

Your estimated due date and conception date from your last period and cycle length, plus how many weeks along you are today.

Your basal metabolic rate and daily calorie burn (Mifflin-St Jeor), with cut, maintain and bulk calorie targets.

The score you need on the final exam to end the course at the grade you want — from your current grade and the final's weight.

Your credit-weighted GPA on the 4.0 scale — list each course with its credits and letter grade, add as many as you like.

Body-fat percentage by the US Navy tape method from height, neck, waist and hip, with an essential-to-obese band for your sex.

How much water to drink per day — ounces, litres and glasses — from your weight, exercise minutes and climate.

Tip, total and each person's share of the bill — quick tip buttons or a custom rate, and an option to round shares up to whole dollars.

How long a book or article takes to read at your pace, and how many pages a day to finish it by a deadline.

Permutations and combinations of n choose k, plus the chance of at least one success in N trials from a single-event probability.

An estimate of your blood alcohol content (Widmark) from drinks, size, ABV, weight, sex and hours — with the 0.04 and 0.08 lines flagged.

Your max heart rate and the five training zones in bpm — straight percent-of-max or Karvonen using your resting heart rate.

Your course grade from weighted categories — homework, quizzes, midterm, final — the weighted average and the letter it earns.

Itemized operating-torque calculator for concentric (resilient-seated) butterfly valves: seating + bearing + packing, with manufacturer calibration and actuator sizing. Built around the AWWA M49 component method.

Multi-room paint estimator with brand/quality paint lookup table, labor cost estimate, and profit margin analysis

Estimate fountain water loss from evaporation physics (surface area, water temp, wind, humidity) and how often to top off the reservoir. Built by Steve Strong.

5 geometric volume calculators with SVG diagrams