Free, privacy-friendly tools you won't find everywhere

UtilityForge is a small collection of practical utilities for developers, designers, writers, marketers and anyone who works with dates, networks or money. Every tool runs inside your browser: nothing you type is uploaded or stored on our servers.

Our tools

DeveloperCron Expression Explainer & Next Run CalculatorDecode any 5-field cron expression and see its next scheduled run times.NetworkingCIDR Subnet CalculatorNetwork address, broadcast, mask, wildcard and usable host range for any IPv4 CIDR block.DeveloperChmod Permission CalculatorConvert Linux file permissions between checkboxes, octal and symbolic notation.Design & AccessibilityWCAG Colour Contrast CheckerCheck text and background colour pairs against WCAG 2.1 AA and AAA contrast requirements.FinanceLoan Prepayment Savings CalculatorSee how much interest and time you save by paying extra on a home, car or personal loan.Date & TimeBusiness Days CalculatorCount working days between two dates or add business days to a date, with custom weekends and holidays.Writing & CodeText Difference CheckerCompare two blocks of text line by line and see exactly what was added or removed.Writing & SEOKeyword Density & Phrase AnalyzerFind the most repeated words and 2-3 word phrases in any text, with counts and density.MarketingUTM Campaign Link BuilderCreate clean, consistent UTM-tagged URLs for Google Analytics campaign tracking.Design & MediaAspect Ratio & Resolution CalculatorSimplify any width and height to a ratio and scale dimensions without distortion.Date & TimeMeeting Time Zone PlannerFind the overlap in working hours between up to four time zones for a given date.DeveloperUmask CalculatorSee the default file and directory permissions that any umask value produces.

Latest guides

8 min readYour Cron Job Isn't Running: A Debugging Checklist That Starts With the Boring StuffNine real reasons a cron job silently fails, in the order you should check them, from the percent-sign gotcha to the missing newline.8 min readPlanning a Cloud Network: Choosing CIDR Blocks You Won't Regret in a YearHow to pick VPC and subnet sizes, why cloud providers reserve addresses, and a sizing table with real usable-host counts.8 min readWhen You Prepay Matters More Than How Much: Numbers From a 50-Lakh Home LoanWorked numbers showing how timing, a small EMI round-up, and monthly extras change interest on a 20-year, 8.5% loan.7 min readSeven Popular Colours That Fail Contrast on White, and the Darker Shades That PassReal hex codes, real ratios and a tested replacement for each, so you can keep the look and meet WCAG AA.6 min readumask Explained: Why Your New Files Are 644 and How to Change ThatThe simple subtraction behind default Linux permissions, with the four umask values you'll actually meet.7 min readThe Three Weeks a Year India–US–UK Meetings Quietly BreakWorked examples of how daylight saving changes the gap between IST, London and New York, and what to do with recurring calls.

See all guides →

Why UtilityForge?

Specialised, not generic. You can find a word counter anywhere. We focus on useful utilities that are harder to find done well: subnet maths, cron schedules, WCAG contrast checks, loan prepayment modelling and cross-time-zone planning.

Private by design. Calculations run locally with JavaScript. We do not need an account, and we never receive your text, numbers or files.

Explained, not just calculated. Each tool page includes a plain-language explanation, step-by-step instructions and answers to common questions, so you understand the result and can trust it.

Free and fast. No sign-up, no downloads, and pages are lightweight so they load quickly on mobile connections.