About PipeSizeCalculator

Free, accurate trade calculators built for people who work with their hands.

What we built

PipeSizeCalculator.com started as a pipe sizing tool and grew into a full suite of 8 free construction trade calculators. Every tool is built around the same principle: give tradespeople and DIYers fast, reliable answers without paywalls, ads or account registration.

Pipe Size CalculatorHazen-Williams equation — PVC, copper, PEX, steel
Concrete CalculatorSlabs, footings, columns — bags or ready-mix
Electrical Load CalculatorBreaker sizing — NEC 125% rule
Wire Gauge CalculatorAWG & mm² — voltage drop calculation
Roof Pitch CalculatorDegrees, percentage, rafter length & roof area
Tile CalculatorFloor & wall tiles with waste allowance
Paint CalculatorLitres & gallons — rooms, walls, ceilings
Stud Spacing CalculatorTimber & metal stud wall framing

Who built it

This site was built by a developer with a background in construction and building services. The formulas used — Hazen-Williams for pipe sizing, NEC 125% rule for electrical, DIN/DVGW for German installations, CTE for Spanish, DTU for French — are the same ones used by professional engineers and tradespeople in each country.

Every calculator has been tested against real-world scenarios and verified against industry standards. The pipe calculator, for example, uses the same Hazen-Williams equation (C values, friction head loss formula) that plumbing engineers use to size commercial water supply systems.

Why it's free

Good tools shouldn't cost money. A plumber on a job site sizing a pipe shouldn't have to subscribe to software to get a reliable answer. Every calculator on this site is completely free, works offline, requires no account, and has no usage limits.

Languages and standards

The site is available in English, Spanish, French and German. Each language version includes region-specific content — local building codes (CTE, REBT, DTU, DIN, VDE, DVGW), materials commonly used in that market, and prices in local currency. The German pages, for example, reference DIN 1988 for pipe sizing and DIN EN 206 for concrete, which are the standards German plumbers and builders actually work to.

Get in touch

Found a bug? Have a suggestion for a new calculator? Want to discuss a sponsorship or partnership? Contact us here or email hello@pipesizecalculator.com.