# CalcuCrvFit — Curve Fitting Calculator

> Curve Fitting Calculator (iPhone/iPad app by John Durand.)

- Source: https://appshunter.io/ios/app/calcucrvfit/id1318833187 (this page in markdown: same URL + `.md`)
- Developer: [John Durand](https://appshunter.io/developer/1296351579)
- Category: Business, Education
- Price: $0.99
- Age rating: 4+
- Requires: iOS 13.0 · 2 MB
- Languages: English
- Released: 2018-01-10
- Data updated: 2025-01-09
- User reviews in markdown: https://appshunter.io/ios/app/calcucrvfit/id1318833187/reviews.md

## What is CalcuCrvFit?

Features include:
- Reverse Polish Notation scientific calculator
- Hundreds of built in unit conversion factors
- Stores multiple datasets, 
- Datapoint storage is unlimited
- Performs the following curve fits:
   * Linear Fits
   * Polynomial fits up to 9th degree in standard mode
   * Polynomial fits up to cubic fit for calibration mode
   * Exponential fits
   * Power fits
- Calculates the goodness of fit (r2 and RPD), 
- Graphs the given values verses the predicted values,
- Calculates predicted values (X or Y) from the user’s input,
- Print or email reports and graphs in PDF format. 
- Graphs can be printed in landscape or portrait mode
- Conversion of graph PDF document to image (bmp, jpeg, tiff, png)
- Import data from comma quote delimited files.
- Export x, y and coefficient data to a delimited file
- Contains a user guide
- Supports IOS 13 dark mode

The advantage of the curve fitting module is that it provides two modes of curve fitting: Calibration mode and Standard mode.  In the Calibration Mode, an inverse prediction of X (abscissa) from Y (ordinate) is performed. As an example, if x is standard concentration values in mg/L and y is absorbance, then you can predict the concentration in mg/L from any absorbance value. The application derives X in  linear and polynomials  of the second and third degree by using equation roots. 

The standard mode is available to fit datasets where high degree (up to 9th degree) polynomial fits are required or the Y needs to be predicted from X.  Both modes provide the goodness of fit by calculating the correlation coefficient (r^2) and the relative percent difference (RPD) between the measured values and the predicted values.

The calculator is a scientific Reverse Polish Notation calculator and it can be also used to enter dataset points rapidly.


## Version history (last 5 releases)

### 4.3 — 2021-09-30

Updated to support 8.3-inch Liquid Retina display.

### 4.2 — 2020-02-25

Changed the color of the data input prompt so it is readable in dark mode. Also, fixed an issue where the constant button would sometimes not retrieve the stored constant.

### 4.1 — 2019-12-04

- Dark mode support that is available in IOS 13.
- The PDF version of the graph can be converted into an image (JPEG, PNF, BMP, TIFF) for inclusion in reports.
- The calculator status is saved when you exit the application and restored the you reenter it so you can continue with the calculation where you left off. 
- Import comma-quote delimited files.

### 4.0 — 2019-07-20

New features include: 
- Power and exponential fits added to the existing linear and polynomial fits,
- Export data points and fit coefficients to a delimited file

### 3.0 — 2019-04-15

A scientific Reverse Polish Notation Calculator was added that can also be used to enter data points into a dataset. The calculator has a unit conversion function that has hundreds of possible conversions.

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## More apps by John Durand

- [EZ Mailing Labels II](https://appshunter.io/ios/app/ez-mailing-labels-ii/id1543219946)
- [EZ Mailing Labels III](https://appshunter.io/ios/app/ez-mailing-labels-iii/id6477535937)
- [EZ Mailing Labels 4](https://appshunter.io/ios/app/ez-mailing-labels-4/id6575350692)

All apps by John Durand: https://appshunter.io/developer/1296351579

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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 2025-01-09.*