u/After-Ad3509

I'm building a free browser-based electronics calculator workbench and I'm trying to make it genuinely useful for DIY electronics projects.

I'm aiming for calculators that include clear equations, units, assumptions, warnings, tolerance-aware inputs where useful, corner case outputs, guides, and worked examples.

Full disclosure: this is my project. It's called ECAD Workbench, and I can link it if that’s allowed, but I don't want to spam the sub.

The types of calculators I'm working on or considering include:

• LED resistor/current calculations
• Voltage dividers and divider loading
• Battery life using active/sleep current profiles
• Regulator dissipation and thermal margin
• I2C pull-up sizing
• PCB trace current and voltage drop
• Capacitor charge/discharge timing
• RC filters
• Crystal load capacitance
• Decoupling/PDN sanity checks

For people building small electronics projects, Arduino/ESP32 boards, battery-powered devices, sensor boards, repair mods, or custom PCBs:

• What calculators would you actually use?
• What calculator results would you not trust unless the page explained the assumptions properly?
• Are there any common DIY electronics mistakes that would make good calculator/guide topics?