Online Scratch Card - Virtual Reveal & Surprise Message
Create a virtual scratch card with a hidden message or prize. Send the link; recipient scratchs with mouse/touch. Canvas-based.
UD5 Toolkit
Create Apple Calendar & Microsoft Outlook compatible event files instantly. Download or copy.
METHOD:REQUEST protocol, which tells calendar applications to treat this as a meeting invitation rather than a simple event. Attendees will see accept/decline options when they open the file. This works seamlessly with both Apple Calendar and Microsoft Outlook, enabling proper RSVP tracking.
TZID parameter. This means the event time is stored with its original timezone context. When someone in a different timezone opens the file, their calendar app automatically converts the event to their local time. For UTC events, we use the standard "Z" suffix notation. This ensures maximum compatibility—Apple Calendar, Outlook, and Google Calendar all correctly interpret timezone-aware ICS files. We recommend always selecting the timezone where the meeting physically takes place for the most accurate scheduling.
VALARM component in the ICS file. You can add reminders like "15 minutes before," "1 hour before," and "1 day before" to the same event. Both Apple Calendar and Outlook support multiple alarms per event. You can also enter custom minute values for complete flexibility—for example, 45 minutes before or 3 hours before. Reminders appear as pop-up notifications on your device when the trigger time is reached, helping you stay on top of your schedule.
Create a virtual scratch card with a hidden message or prize. Send the link; recipient scratchs with mouse/touch. Canvas-based.
Enter a year to check if it is a leap year. Shows the rule explanation and next/previous leap years. Simple reference.
Create an HMAC (Hash‑based Message Authentication Code) using SHA‑256 or SHA‑512 with a secret key. Verify data integrity. Local.
Create custom flashcards and review them with a simple spaced repetition algorithm. Data stored in your browser. No sign-up required.
Convert between currencies using manually updated or default rates. Great for estimation when offline. Local settings.
Estimate solar heat gain through windows given SHGC and orientation. Understand cooling loads. Simple educational physics tool. Local.
Convert across length, mass, speed, temperature, data, and more. Search any unit and type. Compact and fast.
Create a completely randomly generated alien script with fonts and syllable patterns. Translate your name into alien. Fun.
Choose colors and knot types to design a bracelet pattern. See visual guide. Save locally.
Select a destination language and generate a printable mini phrasebook with essential greetings, directions, food, and emergency phrases. Local only.
Compute probability for simple events, as well as permutations and combinations (nPr, nCr). Useful for statistics and game theory. Browser-based math.
Select two birth year animals to see a fun compatibility rating and description. Pure cultural entertainment.
Input telescope and eyepiece parameters to see a simulated view of the Moon or Andromeda. Plan observations.
Choose colors and knots to design a friendship bracelet pattern. View the simulated final result.
Brainstorm information architecture: enter a parent term and generate child terms and related concepts. Quick idea list.
Click cells to see patterns, highlight multiples. Visual way to learn multiplication. Print empty grid.
Design friendship bracelet patterns by placing forward and backward knots on a grid. See a visual preview of the finished bracelet.
Draw a 3D box or room interior by dragging vanishing points. Great for learning perspective drawing. Export as image.
Calculate the area of an irregular polygon by entering its vertex coordinates. Uses the shoelace formula. Pure math.
Draw perfect ellipses by dragging focal points and a point on the curve. See the equation update dynamically. Educational.
Click grid to place beads, choose colors, generate a loom pattern. Download as image.
Enter an original pan size and find an alternative pan with the same batter volume. Never overflow or underfill.
Arrange pre‑drawn comic panels into a strip. Add speech bubbles. Export as image. Fun for kids.
Get a random tattoo concept with style and placement suggestion. For fun and inspiration only. Not real art.
Drag colored shapes to matching outlines. Simple, no-text game for 2-4 year olds. Works on touch devices.
Calculate salt and water for a safe vegetable fermentation. Adjust for pepper weight. Visual brine guide.
Generate a sheet of random arithmetic problems (+, -, Ă—, Ă·) with configurable digits. For kids and brain training.
Approximate conversion from eyeglass prescription to contact lens power. Uses vertex distance formula. For educational purposes only, consult your optometrist.
Design circular string art by ticking nails and seeing simulated thread lines. Adjust number of nails and steps. Export pattern. Local only.
Divide a total bill among multiple people considering tax and service fees. See exactly who pays what.