Free tools.
A curated set of free, no-signup, single-purpose tools we recommend — calculators, encoders, generators, and references for engineers, developers, and writers. All open in a new tab.
Square Footage Calculator
Compute square footage of rooms, lots, or odd shapes — including triangles, circles, and multi-segment layouts.
Percentage Calculator
Every variant of the percentage question: X% of Y, X is what % of Y, percent change, tip splitting.
Age Calculator
Exact age in years, months, days, hours — plus age difference between two dates.
Base64 Encode / Decode
Quick Base64 conversion for strings and files. Useful for embedding images in CSS or decoding JWT tokens.
URL Encode / Decode
Percent-encoding for URLs, including form data. Handles all reserved characters per RFC 3986.
Password Strength Checker
Test password entropy and resistance to common attacks. Runs entirely in your browser; nothing transmitted.
Word Counter
Word, character, sentence, and paragraph counts with reading-time estimate. For essays, articles, and posts.
UUID Generator
Generate UUIDs (v1, v4, v5, v7) in bulk. With validation and format conversion.
JSON Tools
Format, validate, minify, and diff JSON. Plus JSON-to-CSV and schema inference.
Hash Generator
Compute MD5, SHA-1, SHA-256, SHA-512 for strings or files. All hashing runs client-side.
Epoch Time Converter
Convert between Unix timestamps and human-readable dates in any timezone.
Text Repeater
Repeat any text N times with optional separators. Useful for test data, padding, and stress-testing inputs.
Crontab Cheat Sheet
Decode and build cron expressions with a visual editor. Common schedules with one click.
Regex Guide
An interactive reference for regular expressions with examples and a tester for all common flavors.
Hours Calculator
Free hours and timesheet calculator with overtime and pay. Handles breaks, overnight shifts, and decimal hours.
Clock With Us
Online alarm clock, timer, stopwatch, world clock, and time zone converter — all browser-based, no signup.
Margin vs Markup
Convert between profit margin and markup, find break-even, and factor in platform fees, shipping, and tax.
Dimensional Weight Calculator
Billable shipping weight for FedEx, UPS, USPS, DHL and more carriers — compares actual vs volumetric weight.
Box Volume Calculator
Calculate the volume of a box from its length, width, and height in any units. For shipping, storage, and packing.
Girth Calculator
Parcel length-plus-girth against carrier size limits, plus body circumference measurements for fitness tracking.
Solar Calculator
Free, unbiased solar and off-grid calculators — system sizing, savings and payback, and battery banks.
Case Transformer
Convert text between Title Case, sentence case, camelCase, snake_case, kebab-case, and more, with side-by-side preview.
CIDR Calculator
Calculate, split, and visualize subnets. IPv4/IPv6, VLSM planner, cloud-aware reserved IPs, and Terraform export.
Subnet Mask Calculator
Network and broadcast addresses, usable host range, wildcard masks, and VLSM planning for IPv4 and IPv6.
Picture Toolkit
Browser-based image tools — compress, convert, resize, crop, and watermark. Files never leave your device.
Remove Metadata
Strip EXIF, GPS, and hidden metadata from images, PDFs, and Office files — locally in your browser.
These are external sites we like and use. We're not paid to list them, and we don't track outbound clicks. If you've made a free, useful single-purpose tool you'd like considered for this page, get in touch.