# Online Calculators

> Free online calculators: percentages, dates, time zones, resistors, voltage dividers, battery charge time, company cars and more. Fast and without sign-up.

From everyday calculators like percentages and dates to electronics calculators for resistors and voltage dividers: the math happens right in your browser.

## Tools in this category

- [Battery & EV Charge Time Calculator](https://pockettoolbox.org/en/battery-charge-calculator): Calculate charge time, finish time, and costs for EVs and batteries - with charge curve and live tracking.
- [Calendar Week Calculator](https://pockettoolbox.org/en/calendar-week): Show current calendar week (CW) and convert date to calendar week.
- [Capacitor Charge Time Calculator](https://pockettoolbox.org/en/capacitor-charge-time): Calculate the RC time constant and charge/discharge curve of a capacitor through a resistor, including voltage over time, time to reach a target level, and a visual curve.
- [Company Car & Leasing Calculator](https://pockettoolbox.org/en/company-car-calculator): Calculate benefit-in-kind (1%, 0.5% & 0.25% rule), net salary impact, lease factor, and savings compared to private purchase.
- [Cron-Job Visualizer](https://pockettoolbox.org/en/cron-visualizer): Create Cron jobs interactively and visualize execution times on a calendar and timeline.
- [Date Calculator](https://pockettoolbox.org/en/date-calculator): Calculate the duration between two dates or add/subtract days from a date.
- [I²C Pull-up & UART Baud Rate Calculator](https://pockettoolbox.org/en/i2c-uart-calculator): Calculate I²C pull-up resistors from bus capacitance and speed, or find the UART baud rate error for a given MCU clock frequency (ESP32, Arduino, STM32).
- [Percentage Calculator](https://pockettoolbox.org/en/percentage-calculator): Calculates percentage value, rate, percentage change, discount with cash discount, VAT, and tip splitting.
- [Pomodoro Timer](https://pockettoolbox.org/en/pomodoro-timer): A simple Pomodoro timer for productivity and regular breaks.
- [Resistor Calculator (Color Code & SMD)](https://pockettoolbox.org/en/resistor-calculator): Calculate resistance values interactively from 4, 5, and 6 band color codes, convert values back to color codes, or decode SMD markings (3-digit, 4-digit & EIA-96).
- [Stopwatch](https://pockettoolbox.org/en/stopwatch): Precise stopwatch with lap times.
- [Timezone Planner](https://pockettoolbox.org/en/timezone-planner): Find ideal meeting times and plan global appointments by overlapping multiple timezones.
- [Unix Timestamp Converter](https://pockettoolbox.org/en/timestamp): Convert Unix timestamps to human-readable dates and vice versa.
- [Voltage Divider Calculator](https://pockettoolbox.org/en/voltage-divider): Calculate output voltage, quiescent current, and power dissipation of voltage dividers or automatically find the best E12/E24/E96 resistor pairs for your target voltage.

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PocketToolbox (https://pockettoolbox.org/en)