UD5 Toolkit
Concrete Mix Calculator - Online Cement Sand Gravel Ratio Tool
Calculate required bags of cement, sand, and gravel for a given concrete volume using standard mix ratios (1:2:4, etc.). Supports metric and imperial.
Canvas Gradients Playground - Online Linear & Radial
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%
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Drag markers · Click strip to add
Selected Stop
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background: linear-gradient(180deg, #6366f1 0%, #ec4899 100%);
Concrete Volume Calculator – Online Slab, Footing, Column
Calculate cubic yards or meters for various shapes (rectangular slab, circular column, trapezoidal footing). Local math tool.
Yarn Substitution Tool – Online Match Gauge & Yardage
When a yarn is discontinued, find equivalent alternatives by matching weight and gauge. Local reference.
Keyboard Shortcut Trainer – Online Learn VS Code / Figma Keys
Select a tool (VS Code, Figma, etc.) and get random shortcut prompts. Press the keys to practice.
Number Input Step Demo - Online See Validation Behavior
Test min, max, and step constraints on `<input type='number'>`. See how invalid values are handled. Undocumented behavior.
Percentage Calculator - Online Find Percent, Increase & Decrease
Perform common percentage calculations: find percent of a number, percentage increase/decrease, and more. Simple, fast, and always available for free.
Spring Constant & Elastic Energy Calculator – Online Hooke's Law
Enter spring constant and displacement to find force and stored energy. Visual compression.
Tea Brewing Timer - Online Perfect Steep for Green Black Oolong
Select tea type and get recommended steeping time & temperature. Start a visual countdown with an alert. Make every cup perfect. No ads, local.
Shoelace Length Calculator – Online Eyelet Pairs & Pattern
Enter number of eyelet pairs and lacing style to find the correct shoelace length in inches/cm. Never buy too short.
Redirect Path Tracer - Online SEO Redirect Chain Analyzer
Enter a URL and trace the full redirect chain, seeing each hop's status code and location. Identify unnecessary redirects. Client-side fetch.
Horse Feed Calculator - Online Daily Hay & Grain Ration
Estimate daily hay and grain needed for a horse based on weight and workload. Follows 2% body weight rule. Educational reference.
CAGR Calculator - Online Compound Annual Growth Rate
Find the CAGR of an investment given start and end values over a time period. Instant growth rate.
Chicken Feed Ration Calculator – Online Layer, Broiler, Chick
Mix your own feed by entering grain percentages and see the resulting crude protein. Formulate a balanced diet for your flock.
Tea Steeping Timer - Online Perfect Brew Countdown
Choose your tea type and start a precise steeping timer with color‑changing background. Never over‑steep again.
Airflow CFM Calculator - Online HVAC Duct Sizing Tool
Calculate airflow in cubic feet per minute given velocity and duct diameter. Simple HVAC reference. Local only.
Resin Casting Volume Calculator – Online Mold & Part A/B
Enter mold dimensions or water weight to get total resin needed, including Part A and B.
Compound Interest Calculator - Online Investment Growth Tool
Project how your savings and investments grow over time with compound interest. Interactive chart and detailed table. Free and anonymous.
Bruise Color Timeline – Online Reference Healing Stages
Visual chart showing the typical colors a bruise goes through from red to yellow. Educational only.
Soda Ash Soak Calculator – Online Tie‑Dye Prep Ratio
Calculate water and soda ash needed to pre‑soak fabric for tie‑dye. Achieve vibrant, long‑lasting colors.
IQR Calculator - Online Interquartile Range & Box Plot
Enter a dataset to compute Q1, median, Q3, IQR, and highlight outliers. Visual box plot generated in canvas.
Simple Interest Calculator - Online Principal Rate Time Tool
Compute simple interest and final amount given principal, annual rate, and duration. Also reverse-calculates rate or time. Local only.
Crochet Hook Size Converter – Online US, UK, Metric, JP
Enter a hook size in any system and instantly see the equivalent in all other standards.
VS Code Shortcuts Cheatsheet - Online Keyboard Shortcuts
Find essential Visual Studio Code shortcuts for Windows, Mac, and Linux. Filter by category. Boost your coding speed with this reference.
Beef Jerky Dehydration Timer – Online Thickness & Time Guide
Calculate dehydrating time based on meat slice thickness and desired texture. Countdown timer with reminders.
Liquid Fertilizer Dilution Calculator – Online Mix Ratio
Calculate how much liquid fertilizer concentrate to add per gallon of water based on desired N concentration.
Interval Timer - Online HIIT & Tabata Workout Clock
Set up high-intensity interval training rounds with work and rest periods. Audio alerts and customizable sets. Runs in background, no download.
Repotting Time Checker – Online Know When to Repot by Roots
Visual guide to identify root-bound plants. Calculates next pot size up. Keep indoor plants healthy.
Knot Strength Efficiency Guide – Online Visual Weakness Chart
Compare common knots by their efficiency percentage and residual strength. Interactive chart with animated diagrams.
Iron Absorption Optimizer – Online Timing & Food Pairing
Schedule your iron supplement away from inhibitors (coffee, calcium). Visual reminder and log.
Sudoku Solver Step-by-Step - Online Visual Deduction
Enter a Sudoku puzzle and watch it solved step-by-step with techniques explained. Learn solving strategies. Local only.