# CalcKing Pro-Professional — Trigonometric functions

> Trigonometric functions (iPhone/iPad app by 文娟 唐.)

- Source: https://appshunter.io/ios/app/calcking-pro-professional/id6758431895 (this page in markdown: same URL + `.md`)
- Developer: [文娟 唐](https://appshunter.io/developer/1870722016)
- Category: Utilities
- Price: Free with in-app purchases
- Age rating: 4+
- Requires: iOS 15.0 · 2 MB
- Languages: American English, Chinese (Simplified, China)
- Released: 2026-03-12
- Data updated: 2026-06-23
- User reviews in markdown: https://appshunter.io/ios/app/calcking-pro-professional/id6758431895/reviews.md

## What is CalcKing Pro?

Professional engineering calculator, the mobile computing tool for engineers!
No ad interference: Specifically designed for engineers, with a pure usage experience and no pop-up ads.
Full coverage of core functions:
Basic scientific calculations: Trigonometric functions, logarithms and exponents, power operations, constant calls (π/e, etc.), support for degree/radian conversion, meeting general calculation needs.
12 types of unit conversions: Length, weight, area, volume, temperature, speed, etc., covering meters/cm/inches, kilograms/pounds, etc. Common sub-units, one-click quick conversion.
Base conversion: Supports binary, octal, decimal, and hexadecimal conversions, suitable for electronic/computer engineering scenarios.
Specialized engineering calculations: Built-in mechanics, circuits, materials, etc. Modules, solving professional problems such as force on inclined planes, series resistors, etc.
User-friendly design:
Portrait operation: Compatible with iPhone, using the vertical screen in engineering scenarios is more convenient.
Local saved calculation history: Automatically records the last 20 calculations, not lost when uninstalling, and can be recalled at any time.
Precise adaptation: Optimized for on-site work by engineers, clear display of large numbers, real-time input verification to avoid errors.
Efficient work, time and effort-saving: From basic formulas to complex engineering problems, all are covered, helping you focus on core work!

## Pricing and in-app purchases

Base price: Free.

**One-time purchases**

| Purchase | Price | Type |
| --- | --- | --- |
| 解锁功能 | $3.99 | one-time |



## Version history (last 4 releases)

### 1.0.3 — 2026-04-14

This update:
1. Fixed bugs.

### 1.0.2 — 2026-03-23

This update:
1. Fixed bugs.

### 1.0.1 — 2026-03-16

This update:
1. Fixed bugs.

### 1.0.0 — 2026-03-12

No release notes.

## More apps by 文娟 唐

- [LED Chat-LED Bullet comments](https://appshunter.io/ios/app/led-chat-led-bullet-comments/id6758072575)
- [Aegisix](https://appshunter.io/ios/app/aegisix/id6758121607)
- [ProWatermark+](https://appshunter.io/ios/app/prowatermark-plus/id6758123841)

All apps by 文娟 唐: https://appshunter.io/developer/1870722016

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*Data collected daily from the US App Store and indexed by [AppsHunter](https://appshunter.io/). User reviews are verbatim App Store reviews. Ratings, prices and chart positions refresh continuously; this snapshot is from 2026-06-23.*