# LSPIV vs Uncertainty Calculator

The clearest difference is price: LSPIV at Free against Uncertainty Calculator's $3.99. LSPIV also leads on iOS requirement (11.0 vs 17.0). Uncertainty Calculator's advantage is update cadence (every 3 months vs every 13 months). On rating, ratings volume, ads and in-app purchases there is nothing between them.

LSPIV is free to download; Uncertainty Calculator costs $3.99 up front. Neither carries in-app purchases, so what you see is what you pay.

On the App Store both sit at effectively the same score — 5.0 for LSPIV against 5.0 for Uncertainty Calculator. Both are backed by a comparable volume of ratings — 1 and 1 respectively.

LSPIV ships an update every 13 months, Uncertainty Calculator every 3 months. The most recent releases landed on November 1, 2026 and November 2, 2026 respectively.

## The numbers

| Metric | LSPIV | Uncertainty Calculator |
| --- | --- | --- |
| Price | **Free** | $3.99 |
| Rating | [5.0 (1 ratings)](https://appshunter.io/ios/app/lspiv/id981387743/reviews) | [5.0 (1 ratings)](https://appshunter.io/ios/app/uncertainty-calculator/id1170905440/reviews) |
| Number of ratings | 1 | 1 |
| In-app purchases | No | No |
| Ads | No | No |
| Update frequency | Every 13 months | **Every 3 months** |
| Monetization | **Free** | Paid |
| Size | 71 MB | 1 MB |
| Requires iOS | **11.0** | 17.0 |
| Devices | **iPhone, iPad, iPod** | iPhone, iPad |
| Age rating | 4+ | 4+ |
| Developer | [Ryota Tsubaki](https://appshunter.io/developer/981387742) | [Roman Volinsky](https://appshunter.io/developer/977951850) |

## What reviewers say

### LSPIV

[App page](https://appshunter.io/ios/app/lspiv/id981387743)

This application enables large-scale particle image velocimetry (LSPIV) using a smartphone. It offers a non-intrusive method for measuring water surface velocity distribution in both field and lab settings. The app provides instant ortho-rectification of captured images without needing ground control points.

**Highlights:** Large-scale particle image velocimetry, Water surface velocity measurement, Non-intrusive velocimetry, Smartphone implementation, Instant ortho-rectification, No GCPs required

**Features:** macOS Compatibility

**In-app purchases:** none


### Uncertainty Calculator

[App page](https://appshunter.io/ios/app/uncertainty-calculator/id1170905440)

This app allows users to perform error propagation calculations for mathematical expressions involving uncertain variables. It supports absolute and relative error inputs, various functions, and trigonometric calculations in degrees or radians. The tool helps ensure accurate reporting of results based on estimated errors.

**Highlights:** Error propagation calculations, Absolute and relative error input, Support for mathematical functions, Trigonometric calculations (degrees/radians), Variable combination in expressions, Significant figure guidance

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

**In-app purchases:** none


## Frequently asked questions

### Is LSPIV free?

LSPIV is free to download, with no in-app purchases.

### Is Uncertainty Calculator free?

Uncertainty Calculator costs $3.99, with no in-app purchases.

### Which has better reviews, LSPIV or Uncertainty Calculator?

LSPIV and Uncertainty Calculator are both rated 5.0 out of 5 on the App Store, from 1 and 1 ratings respectively.

### Do LSPIV or Uncertainty Calculator have ads?

Neither LSPIV nor Uncertainty Calculator shows ads.

### Which is updated more often, LSPIV or Uncertainty Calculator?

LSPIV ships an update every 13 months, and Uncertainty Calculator every 3 months. Most recently, LSPIV was updated on November 1, 2026 and Uncertainty Calculator on November 2, 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.*