Free tools network

Size off-grid and backup battery banks and solar arrays with the engineering most sales tools skip — real usable capacity, C-rate, voltage and chemistry.

Professional solar sizing and design tools for installers and serious DIY builders, covering a photovoltaic system from panels through to storage.

Size a home backup generator or battery system from your real loads — running and starting watts, runtime, fuel and transfer-switch sizing.

Calculate voltage drop and the correct wire gauge for any DC or AC run across NEC, CEC, BS 7671, AS/NZS and IEC standards, so you don't lose power or overheat conductors.

Work out the air-conditioner tonnage and cooling load a room or whole home needs from area, climate, insulation and sun exposure, so you neither under- nor oversize the unit.

Concrete and bulk-material calculators that work the way contractors do, in cubic yards, for slabs, footings, walls and stairs, with bag counts and a waste margin built in.

Measure square footage for floors, walls, rooms and land across many shapes including rectangles, triangles, circles and irregular layouts, with unit conversion handled for you.

Calculate the volume and capacity of boxes, cartons and rectangular containers in any units, useful for packing, shipping and storage planning.

Find the volume and fill level of tanks in many shapes — cylindrical, oval, rectangular and capsule, horizontal or vertical — for water, fuel and chemical storage.

Compute dimensional (volumetric) weight for FedEx, UPS, USPS and other carriers and compare it against actual weight, so you can predict shipping charges before you ship.

Measure a package's girth and combined length-plus-girth and check it against carrier oversize limits before you pay for shipping.

See the full lifetime cost of a mortgage or loan — the total interest paid, the amortization schedule and the effect of extra payments — so you know what borrowing really costs.

An EMI calculator built for India, covering home, car and personal loans plus credit-card EMI plans with GST, and the difference between EMI in advance and in arrears.

Convert between margin and markup and price products correctly, clearing up the common confusion between the two that quietly erodes profit.

Handle every kind of everyday percentage problem — percentage of a number, percentage change, increase, decrease and reverse percentages — in one clear tool.

Format, validate, minify and explore JSON in your browser, with a tree viewer that makes large or messy payloads easy to read and debug.

Encode text and files to Base64 or decode them back, entirely client-side so nothing you paste ever leaves your machine.

Percent-encode and decode URLs and query strings so special characters are transmitted safely, with full Unicode support.

Generate MD5, SHA-1, SHA-256 and other cryptographic hashes from text or files for checksums, integrity checks and fingerprinting.

Generate UUIDs in bulk and learn how the different versions work, with copy-ready output for development and testing.

Build, test and understand regular expressions with live matching and a reference that explains each token in plain language.

Build cron schedules visually and read back exactly when a crontab expression will run, with a cheat sheet of common patterns.

Convert between Unix epoch timestamps and human-readable dates in any time zone, in seconds or milliseconds, in both directions.

Work out network and broadcast addresses, host ranges and subnet sizes from CIDR notation, with clear breakdowns for network planning.

Calculate subnet masks, host counts and address ranges, with worked examples and code snippets in several languages for network engineers.

Generate barcodes and QR codes in many formats and export them print-ready as PNG or PDF, all rendered locally in your browser.

Strip hidden metadata — EXIF, location, author and more — from images, PDFs, Office files, audio and video entirely in your browser, so nothing is ever uploaded.

Merge, split, compress, rotate and password-protect PDF files client-side, keeping your documents private because they never leave your device.

Convert color codes between HEX, RGB, HSL and more, build palettes and gradients, and export tokens for SwiftUI, Flutter and Jetpack Compose.

A toolkit of browser-based image utilities for resizing, converting and editing pictures without uploading them anywhere.

Count words, characters, sentences and paragraphs and estimate reading time as you type, useful for essays, articles and content limits.

Convert text between upper case, lower case, title case, sentence case and more in one click, handy for cleaning up copy and code.

Repeat, duplicate and generate blocks of text quickly, with control over separators and counts for testing and formatting.

A fast reference and converter for units of length, weight, volume, temperature and more, with the common conversions you actually look up.

Add up the hours between start and end times, including overnight spans and breaks, useful for timesheets, shifts and payroll.

Check the current time across world cities and time zones at a glance, for scheduling calls and coordinating across regions.

Calculate exact age in years, months and days, plus milestones, birthday countdowns and age comparisons between people.

Test how strong a password is and how long it would take to crack, with practical guidance, checked locally and never sent anywhere.

A suite of calorie, macronutrient and body-composition calculators — daily calorie needs, protein targets, lean body mass and more — with clear methodology behind every number.

Calculate BMI, BMR, TDEE and macro targets, plan a goal week by week and track progress, with the formulas and assumptions shown.

Solve fraction problems step by step — add, subtract, multiply, divide and simplify — with each working stage shown so you can follow the math.