# Drill Calc vs StudPlan

The clearest difference is price: StudPlan at Free against Drill Calc's $2.99. StudPlan also leads on update cadence (every 2 weeks vs every 18 months). Drill Calc's advantage is in-app purchases (none vs 4) and device support (3 vs 1). On ads there is nothing between them.

StudPlan is free to download; Drill Calc costs $2.99 up front. StudPlan sells 4 in-app purchases, starting at $1.99 per 7 days. Drill Calc asks for nothing beyond the download.

Drill Calc ships an update every 18 months, StudPlan every 2 weeks. Both last shipped on October 4, 2026.

## The numbers

| Metric | Drill Calc | StudPlan |
| --- | --- | --- |
| Price | $2.99 | **Free** |
| Rating | **[4.1 (19 ratings)](https://appshunter.io/ios/app/drill-calc/id304434324/reviews)** | — |
| Number of ratings | **19** | — |
| Positive reviews | 91.7% of reviews | — |
| In-app purchases | **No** | Yes |
| Ads | No | No |
| Update frequency | Every 18 months | **Every 2 weeks** |
| Monetization | Paid | — |
| Size | 5 MB | 3 MB |
| Requires iOS | **12.0** | 17.0 |
| Devices | **iPhone, iPad, iPod** | iPhone |
| Age rating | 4+ | 4+ |
| Developer | [Black Cat Systems](https://appshunter.io/developer/301047032) | [ZHENGQIAO JIANG](https://appshunter.io/developer/1892168889) |

## What reviewers say

### Drill Calc

[App page](https://appshunter.io/ios/app/drill-calc/id304434324)

This utility app helps you determine the correct drill bit size for threaded holes. It supports both inch and metric threads, calculates close and tight fit hole sizes, and provides tables for standard drill bit sizes and pipe information.

**Highlights:** Calculates drill bit size for threaded holes, Supports inch and metric threads, Displays close and tight fit hole sizes, Includes standard inch fractional and numeric drill bit tables, Provides pipe size information, Offers data on common wood screw sizes

**Features:** macOS Compatibility, Vision Pro support

**In-app purchases:** none


### StudPlan

[App page](https://appshunter.io/ios/app/studplan-wall-framing-layout/id6769339554)

**Features:** macOS Compatibility, Vision Pro support

**In-app purchases (4)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Weekly | $1.99 | per 7 days |
| Monthly | $4.99 | per month |
| Yearly | $29.99 | per year |
| Lifetime | $79.99 | one-time |


## Frequently asked questions

### Is Drill Calc free?

Drill Calc costs $2.99, with no in-app purchases.

### Is StudPlan free?

StudPlan is free to download, with in-app purchases available.

### Do Drill Calc or StudPlan have ads?

Neither Drill Calc nor StudPlan shows ads.

### Which is updated more often, Drill Calc or StudPlan?

Drill Calc ships an update every 18 months, and StudPlan every 2 weeks. Most recently, Drill Calc was updated on October 4, 2026 and StudPlan on October 4, 2026.

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*Compared by [AppsHunter](https://appshunter.io/) from daily US App Store data. Review summaries are generated from verbatim App Store reviews.*