Free online tools we recommend.
A curated collection of free calculators, converters, and developer utilities from our network. No signups, no paywalls — just the right tool for the job.
Calculators & Converters
Everyday math tools — percentages, ages, hours, units.
Square Footage Calculator
Calculate square footage for rooms, lots, and irregular shapes. Supports feet, inches, meters, and yards.
thesquarefootagecalculator.com ↗Percentage Calculator
Quickly work out percentages, percentage change, percent of, and tip/discount math.
bestpercentagecalculator.net ↗Age Calculator
Calculate exact age in years, months, days, hours from any date of birth.
theagecalculator.net ↗Hours Calculator
Calculate hours and minutes between two times. Useful for timesheets and payroll.
calculatehours.net ↗World Clock
Live world clock with timezone comparison and meeting planner across cities.
clockwithus.com ↗Epoch Time Converter
Convert between Unix epoch timestamps and human-readable dates in any timezone.
epochtime.tools ↗Unit Cheat Sheet
Quick reference for unit conversions — length, weight, volume, temperature, and more.
unitcheatsheet.com ↗Margin vs Markup
Convert between profit margin and markup, find break-even, and factor in platform fees, shipping, and tax.
marginvsmarkup.com ↗Solar Calculator
Free, unbiased solar and off-grid calculators — system sizing, savings and payback, and battery banks.
prosolarcalc.com ↗Shipping & Measurement
Closely related tools for parcel and dimension math.
Developer Tools
Quick reference and utilities for everyday development work.
Base64 Encoder / Decoder
Encode and decode Base64 strings. Handles text, URLs, and binary file output.
base64decode.tools ↗URL Encode / Decode
Percent-encode and decode URL components for safe transmission of special characters.
urlencodedecode.com ↗UUID Generator
Generate UUID v1, v4, and v7 identifiers. Bulk generation and validation supported.
www.uuidcore.com ↗JSON Tools
Format, validate, minify, and diff JSON. Includes JSON-to-CSV and JSON-to-YAML converters.
jsontools.tools ↗Hash Generator
Generate MD5, SHA-1, SHA-256, SHA-512 and other cryptographic hashes from text or files.
hashgenerator.tools ↗Crontab Reference
Cron expression builder and quick reference for scheduling shell jobs on Linux/Unix.
crontabsheet.com ↗Regex Guide
Regular expression tester, cheat sheet, and pattern library with live matching.
regexguide.com ↗CIDR Calculator
Calculate, split, and visualize subnets. IPv4/IPv6, VLSM planner, cloud-aware reserved IPs, and Terraform export.
cidrcalculator.net ↗Subnet Mask Calculator
Network and broadcast addresses, usable host range, wildcard masks, and VLSM planning for IPv4 and IPv6.
subnetmaskcalc.net ↗Productivity & Text
Text manipulation, password security, and image tools.
Password Strength Checker
Test password strength against modern attack methods. Includes a strong-password generator.
passwordstrength.net ↗Word Counter
Count words, characters, sentences, and paragraphs. Reading time and keyword density too.
wordcounterfree.com ↗Text Repeater
Repeat any string a specified number of times. Useful for testing, padding, and bulk text.
textrepeat.net ↗Case Transformer
Convert text between upper, lower, title, sentence, camel, snake, kebab, and Pascal case.
transformcase.com ↗Picture Toolkit
Browser-based image tools — resize, crop, compress, convert format, and remove backgrounds.
pictoolkit.com ↗Remove Metadata
Strip EXIF, GPS, and hidden metadata from images, PDFs, and Office files — locally in your browser.
removemetadata.tools ↗About this network
These are independent tools we've found genuinely useful — many built by small teams who care about doing one thing well. We share traffic with them because the tools are good, not because of any commercial arrangement that compromises our recommendations.
If you run a free tool that would fit one of these categories, drop us a line at /contact. We add new tools when they meet the bar.