Calculate parameters for monostable and astable circuits. Find component combinations for desired pulse width or frequency. Share circuit files via iCloud Drive or AirDrop.
Timer 555 Calculator Pro by Siu Yuen Ho





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Finding the right timer 555 calculator pro apps can be overwhelming with so many options. We've analyzed 246+ apps to bring you the best choices for 2026, from free options to premium solutions with advanced features.
| # | App | Price | Rating | Ads | In-App Purchases | Updated | |
|---|---|---|---|---|---|---|---|
| 1 | $0.99 | 4.7★ (3) | No | No | May 2026 | ||
| 2 | Free | 3.9★ (8) | No | Yes | Aug 2026 | ||
| 3 | Free | 4.0★ (3) | Yes | No | May 2026 | ||
| 4 | Free | 5.0★ (1) | No | Yes | May 2026 | ||
| 5 | Free | 4.5★ (126K) | Yes | Yes | Sep 2026 | ||
| 6 | $3.99 | 4.8★ (218) | No | No | Sep 2026 | ||
| 7 | Free | — | No | No | May 2026 | ||
| 8 | Free | 4.4★ (1.2K) | Yes | No | Sep 2026 |





Calculate parameters for monostable and astable circuits. Find component combinations for desired pulse width or frequency. Share circuit files via iCloud Drive or AirDrop.





Calculate monostable and astable circuits for electronics projects. Determine pulse width and frequency, find component combinations, and save/upload data. Supports multiple languages.

This utility app helps engineers and hobbyists calculate resistor values for circuits using the Timer IC 555. Simply input frequency, duty ratio, and capacitor values to get the required resistor outputs.