# Stringcalculator vs Surface Builder

The clearest difference is price: Stringcalculator at $2.99 against Surface Builder's $14.99. Stringcalculator also leads on review sentiment (100% vs 80%). Surface Builder's advantage is update cadence (every 3 weeks vs every 16 months) and iOS requirement (13 vs 17.6). On ads, in-app purchases, monetization model and device support there is nothing between them.

Stringcalculator costs $2.99 and Surface Builder $14.99 up front. Neither carries in-app purchases, so what you see is what you pay.

Stringcalculator ships an update every 16 months, Surface Builder every 3 weeks. The most recent releases landed on September 30, 2026 and October 12, 2026 respectively.

## The numbers

| Metric | Stringcalculator | Surface Builder |
| --- | --- | --- |
| Price | **$2.99** | $14.99 |
| Rating | — | **[4.7 (15 ratings)](https://appshunter.io/ios/app/surface-builder/id6449735778/reviews)** |
| Number of ratings | — | **15** |
| Positive reviews | **100.0% of reviews** | 80.0% of reviews |
| In-app purchases | No | No |
| Ads | No | No |
| Update frequency | Every 16 months | **Every 3 weeks** |
| Monetization | Paid | Paid |
| Size | 1 MB | 32 MB |
| Requires iOS | 17.6 | **13** |
| Devices | iPhone, iPad | **iPhone, iPad, iPod** |
| Age rating | 4+ | 4+ |
| Developer | [Martin Uhlig](https://appshunter.io/developer/1414861205) | [4Pockets.com](https://appshunter.io/developer/370131860) |

## What reviewers say

### Stringcalculator

[App page](https://appshunter.io/ios/app/stringcalculator/id1426367350)

Calculate string properties for various instruments. Determine diameter, tension, and tone based on material, frequency, and scale length. Supports multiple units of measurement.

**Highlights:** Calculate string diameter, tension, and tone, Supports gut, nylgut, carbon, Tynex, and nylon strings, Set custom frequencies, Calculate in cm, mm, or inches, Adjustable scale length

**Features:** macOS Compatibility

**In-app purchases:** none


### Surface Builder

[App page](https://appshunter.io/ios/app/surface-builder/id6449735778)

Create custom MIDI control surfaces for audio applications. Design interfaces with buttons, knobs, and faders to send and receive MIDI data, control audio clips, and customize appearance. Supports AUv3 plugins and standalone use.

**Highlights:** Customizable MIDI control surfaces, AUv3 plugin and standalone modes, Send/receive MIDI data (notes, controllers, pitch bend), Audio clip playback control, Multi-scene interface design, Drag and drop interface customization

**Features:** macOS Compatibility

**In-app purchases:** none


## Frequently asked questions

### Is Stringcalculator free?

Stringcalculator costs $2.99, with no in-app purchases.

### Is Surface Builder free?

Surface Builder costs $14.99, with no in-app purchases.

### Do Stringcalculator or Surface Builder have ads?

Neither Stringcalculator nor Surface Builder shows ads.

### Which is updated more often, Stringcalculator or Surface Builder?

Stringcalculator ships an update every 16 months, and Surface Builder every 3 weeks. Most recently, Stringcalculator was updated on September 30, 2026 and Surface Builder on October 12, 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.*