Free Online Calc

Home project calculators

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Estimate materials from room and project dimensions before buying supplies.

Paint Calculator

Estimate how much paint is needed for a wall area from room dimensions, coverage rate, and number of coats.

Wallpaper Calculator

Estimate the number of wallpaper rolls needed for a room from its dimensions and the coverage of each roll.

Flooring Calculator

Estimate flooring material needed for a room, including a waste allowance, from room length and width.

Tile Calculator

Estimate the number of tiles needed to cover an area, including a waste allowance, from tile and room size.

Concrete Calculator

Calculate the volume of concrete needed for a rectangular slab from its length, width, and depth, free and in your browser.

Gravel Calculator

Estimate the volume and mass of gravel needed to cover an area at a chosen depth and material density.

Mulch Calculator

Estimate the volume of mulch needed to cover a garden bed at a chosen depth, in cubic feet or yards.

Fence Calculator

Estimate the number of fence panels and posts needed to enclose a given total fence length, free and in your browser.

Roofing Calculator

Estimate roof surface area from a building footprint and roof pitch, useful for ordering roofing material.

Drywall Calculator

Estimate the number of drywall sheets needed to cover a wall area from the wall and sheet dimensions.

Insulation Calculator

Estimate the number of insulation packs needed to cover an area from pack coverage and area dimensions.

Room Area Calculator

Calculate a rectangular room floor area in square feet or metres from its length and width measurements.

Room Lighting Calculator

Estimate lamp lumens from room area and a chosen illuminance target.

Air Conditioner Size Calculator

Estimate room cooling capacity from volume, sun, people, and equipment heat.

Appliance Energy Calculator

Estimate appliance electricity consumption and cost over a chosen period.

Pool Water Treatment Calculator

Calculate rectangular pool volume and a product amount from its label dose.

Lawn Fertilizer Calculator

Convert a nitrogen target and bag analysis into a product application mass.

Roof Pitch and Rafter Calculator

Calculate roof angle and geometric rafter line length from rise and run.

Foundation Concrete Calculator

Estimate concrete for a strip footing with optional round piers and waste.

Insulation Thickness Calculator

Calculate nominal insulation thickness from added thermal resistance and conductivity.

Stair Calculator

Calculate riser, going, and the 2R + G walking-guide value from finished dimensions.

Weight-Based Dose Reference

Reference-only mg/kg multiplication with a verified maximum single dose.

Recipe Calorie Calculator

Estimate total and per-portion calories from ingredient weight and energy density.

Glycaemic Load Calculator

Calculate glycaemic load from available carbohydrate in a portion and glycaemic index.

Cooking Time Calculator

Scale a known cooking time by product weight as an estimated time to begin checking.

Room Paint Estimator

Calculate paint purchase quantity after openings, coats, coverage, and reserve.

Tile Layout Estimator

Calculate tile count and boxes from room dimensions, tile face, and cut allowance.

Wallpaper Repeat Estimator

Calculate wallpaper rolls from drop length, roll dimensions, and pattern repeat.

Soil and Mulch Volume Estimator

Calculate settled bed volume, bag count, and approximate delivery mass.

Choosing a home tool

Each card opens a separate tool with its own assumptions and explanation. Choose the page that names the outcome you need instead of forcing an adjacent calculator or picker to stand in for it.

The collection separates tasks when the inputs or the decision being supported are different. That makes a result easier to reproduce and easier to explain later.

Compare scenarios, not guesses

Open a tool, inspect its defaults, and replace them with values you can explain. Run more than one scenario when a small change matters. Record the inputs with the output; that is the only way to make a later comparison meaningful.

A home result is strongest when it is attached to a date, a source, and a clear unit. Keep those three details with the number: they reveal whether two apparently similar scenarios can really be compared.

Use the category cards to separate an estimate from a quote, a historical record from a forecast, and a one-time charge from a recurring commitment. The distinction often matters more than the last decimal place.

Limits of the collection

These browser tools show the consequence of entered values. They do not know facts that are not supplied, and they cannot settle a decision that needs professional, legal, medical, financial, safety, or policy context. Use the result to frame a question, then verify the relevant source before acting.

Enter your values, review the result, then use it with confidence.

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