# Calculator of Air — Psychrometric Charts Tool

> Psychrometric chart calculator for moist air properties. (iPhone/iPad app by yoshihito sakagami.)

- Source: https://appshunter.io/ios/app/calculator-of-air/id1112518507 (this page in markdown: same URL + `.md`)
- Developer: [yoshihito sakagami](https://appshunter.io/developer/1112518506)
- Category: Productivity, Utilities
- Price: Free
- Rating: 4.60/5 from 14 App Store ratings · 11 written reviews indexed
- Age rating: 4+
- Requires: iOS 15.6 · 6 MB
- Languages: American English, Japanese, Chinese (Traditional, Taiwan)
- Released: 2016-05-12
- Data updated: 2026-08-20
- Monetization: ad-supported
- User reviews in markdown: https://appshunter.io/ios/app/calculator-of-air/id1112518507/reviews.md

## What is Calculator of Air?

This is a psychrometric (moist air) calculation app used in over 20 countries worldwide.
It allows you to quickly and easily calculate humidity-related properties with a calculator-like interface.
The app adopts the Wexler–Hyland formulation combined with numerical analysis, providing highly accurate and stable results even under extreme atmospheric conditions.

Supported parameters
The following six parameters are supported:

* Dry-bulb temperature
* Wet-bulb temperature
* Dew point temperature
* Relative humidity
* Humidity ratio
* Enthalpy

By entering any two of these parameters, all remaining values are calculated automatically.
For example, you can determine the dry-bulb temperature when the dew point and relative humidity are known.
Ideal for HVAC design, cleanroom management, and industrial drying processes where precision is non-negotiable.
When used together with the companion app “HumidCalc”, additional air-property parameters can be viewed
(please refer to the companion app description for details).

■ Input range and safety checks
* Temperature: -273.15 °C to 99.97 °C (-459.67 °F to 211.95 °F)
* Relative Humidity: 0 %RH to 100 %RH
* Atmospheric pressure is fixed at the standard atmospheric pressure (1013.25 hPa / 29.92 inHg).
If physically invalid values are entered(e.g., wet-bulb temperature higher than dry-bulb temperature), an error message is displayed before calculation is executed.

■ Additional features
* Supports both Celsius (°C) and Fahrenheit (°F)
* Toggleable click sound
* Available in Japanese, English, and Traditional Chinese

■ Memory function
After performing a calculation, tapping one of the following buttons(Dry-bulb, Wet-bulb, Dew point, Relative humidity, Absolute humidity, or Enthalpy) stores that value for subsequent calculations.
By using this function, continuous air-state calculations are possible.
For example, when outdoor temperature and humidity and indoor temperature are known(assuming no latent heat load), you can first calculate and store the outdoor dew point, then input the indoor temperature to easily obtain the indoor humidity.

■ Disclaimer
1. Recommended operating temperature range is approximately 0 °C to 40 °C.
Extremely unusual conditions may result in inaccurate calculations.
2. Minor numerical errors may occur due to floating-point arithmetic.
3. The developer assumes no responsibility for any damages resulting from the use of this app.

## Key features

- Calculate six humidity parameters
- Accurate results under extreme conditions
- Supports Celsius and Fahrenheit
- Input range and safety checks
- Memory function for continuous calculations
- Available in multiple languages

## Recent user reviews (10 of 11)

All indexed reviews: https://appshunter.io/ios/app/calculator-of-air/id1112518507/reviews.md

### 3/5 — 惜しい

*2026-07-10*

絶対湿度の単位がkg/m3なら完璧だった

**Developer response:** レビューを投稿して頂いてありがとうございます！
一点確認ですが、絶対湿度の単位は「g/m3」ではなくて「kg/m3」でしょうか？
「kg/m3」だと手の打ちようがないのですが、もし「g/m3」なら、姉妹アプリ「湿度の計算」と連携して、本アプリで計算した「kg/kg」の絶対湿度を「g/m3」に変換して表示する事ができます。
以下は、その手順です。

(1)まずApp Storeから「湿度の計算」をダウンロードします。
(2)次に本アプリを起動して、「kg/kg」の絶対湿度を計算して下さい。
(3)すると、「計算実行」ボタン上に「湿度の計算へ >」と言うボタンが表示されますので、このボタンを押して下さい。
(4)ボタンを押した後に「湿度の計算」が自動的に起動しますので、「湿度の計算」内の「絶対湿度」の項目をご確認ください。
本アプリで計算した「kg/kg」の「絶対湿度」が「g/m3」の「絶対湿度」に変換されて表示されています。

もし空調設計さんが「kg/m3」あるいは「g/m3」の「絶対湿度」の入力を希望される場合は、残念ですが、上記の方法では対応できません。
ユーザーの皆様から「kg/m3」あるいは「g/m3」の「絶対湿度」の入力機能を追加して欲しいとの要望の声が高まれば、機能の追加を検討させて頂きますが、現在の所は、その様な機能を追加する予定はございません。

### 5/5 — Love the App, Update Broke Display

*2026-01-14*

As an HVAC controls technician this app is incredibly useful. I use this app all the time. 

The latest update broke the display though, now the app is only rendering in the upper left-hand corner of my screen with a big black border around the rest of the screen. I’m on an iPhone 17 Pro.

**Developer response:** Thank you very much for your report, and I sincerely apologize for the delayed response.

I truly appreciate you taking the time to let me know about the issue.
Could you please provide a bit more detail about the layout problem occurring on your iPhone 17 Pro?

It would be very helpful if you could also let me know which version of iOS is installed on your device.

I am currently investigating this issue and plan to release a new version with improvements in the near future. However, since the exact cause has not yet been fully identified, it is possible that the same issue may still occur in the upcoming version.

I apologize for the inconvenience and would greatly appreciate your reply.

### 5/5 — Good app

*2023-05-19*

I’ve been using this for a while, it works !

**Developer response:** Sorry for the very late reply.
Thank you for your high evaluation!
The "Calculator of Air" implements a memory function, and by utilizing this function, you can use this application even more conveniently.
As an example, we will explain how to calculate the relative humidity when outdoor air is taken into a room and then heated.
＊When humidification is not performed.

1: Enter the temperature and humidity of the outside air into the "Calculator of Air".
2: Press the "Dew Point" button.
3: Next, press the "TEMP." button and after entering the indoor temperature, press "ENTER".

With this simple operation, you can calculate the indoor humidity.
If you have a chance, please try it.

### 4/5 — Good but too many digits

*2020-08-05*

There are way too many digits in the output values. I’d suggest 3 significant figures or make it a user option. A very useful app otherwise!
SteveK

**Developer response:** I sincerely apologize for the delay in my reply to you.
There is a way to alleviate the inconvenience caused by the large number of digits in this app.
The app has a function where if you press "TEMP." or "Wet Bulb" or "Dew Point" or "HUMID." or "HUM Ratio" or "Enthalpy" after performing a calculation, the value of the button you press will be retained and all other values will be erased.
With this function, for example, if you are calculating the outdoor dew point temperature from the outdoor temperature and outdoor humidity, and then the indoor humidity from the indoor temperature and the outdoor dew point temperature, then you can easily calculate the indoor humidity from the operations described below.

(1)First of all, calculate the dew point temperature from the outdoor temperature and the outdoor humidity using this app.

(2)In that state, please tap the "Dew Point" button. All numerical values ​​other than "Dew Point" are erased from the calculation result screen, and only the numerical value of "Dew Point" remains.

(3)In that state, enter the indoor temp and tap the "ENTER" button. This app calculates indoor humidity.

I'm sorry, I'm Japanese so I'm bad at English.

### 5/5 — 食品の乾燥に利用してます

*2020-02-03*

気温、相対湿度から瞬時に絶対湿度を計算してくれるので、非常に重宝してます！
作成者さんありがとう！

**Developer response:** 高評価ありがとうございます！
びびにこ様は本アプリで気温と相対湿度から絶対湿度を算出しているとの事ですが、その様な使用用途ならば、拙作「湿度の計算」の方が向いているかもしれません。
拙作「湿度の計算」は気象情報から直接、絶対湿度を算出する事ができますので、気温や相対湿度を計測したり調べたりする手間が省けて便利だと思います。
是非、一度ご検討ください。

〜アプリ開発者より〜

### 1/5 — Enthalpy?

*2019-11-29*

Just to cross ck proper use:

1) Don’t I need return & supply WB to ascertain change in ethalpy?  There is only 1 temp & 1 WB entry - so how are we calc enthalpy

2) For TTL btu change I’d need the enthalpy X ACFM.  Where is the function to make this final reading?

**Developer response:** I read your review, but there are some incomprehensible points in your review, and your review has words that I don't understand.
The following is a summary of those things, so please have a look.


For question 1, you may have misunderstood this app.
This app is an application to facilitate the calculation of humidity charts, but it's not an application for checking changes in enthalpy, so there's only 1 TEMP and 1 WB entry.
By the way, the approximate formula for calculating enthalpy(btu/lb) is as follows.

btu/lb = 0.24t + (0.44t + 1061.13)x

t --- Fahrenheit temperature(℉)
x --- Humidity ratio(lb/lb)


For question 2, I am sorry, I don't understand the meaning of the following words.

- TTL btu
- X ACFM

If you explain that to me, I may be able to give you good advice.

### 5/5 — Great app

*2019-09-10*

Saves a lot of time instead of referring back to a psychometric chart

**Developer response:** Thank you so much for the good rating.
I am very surprised that this app is also used in the UK.
I am very happy, so I decided to drink English breakfast tea tomorrow morning.(^_^) (＊By the way, I am Japanese)
どうもありがとう！(Thank you so much!)

### 5/5 — very good

*2019-06-17*

I need to calculate the RH% inside a house given the outside temp, outside RH%, and indoor temperature. This requires two steps. First calculate dew point of outside, then using same dew point and indoor temp, calculate indoor RH%. But this calculator erases the dew point when I’m at step 2 entering the indoor temp. I have to memorize the dew point and re-enter it. Another minor thing is it displays too many digits.
P.S. The developer taught me a trick. At step 2 before entering the temp, press the dew point button first, then the dew point number will stay. I added one more star to the review.

**Developer response:** I sincerely apologize for the delay in my reply to you.
The problem is solved if you operate the app in the way I will explain now.

(1)First of all, calculate the dew point temperature from the outside temp and the outside RH% using this app.

(2)In that state, please tap the "Dew Point" button. All numerical values ​​other than "Dew Point" are erased from the calculation result screen, and only the numerical value of "Dew Point" remains.

(3)In that state, enter the indoor temp and tap the "ENTER" button. This app calculates indoor RH% as you wish.


I'm sorry, I'm Japanese so I'm bad at English.

P.S : Thank you so much for you added one more star!
I am glad to be of service to you.
ありがとう！(Thank you!)

### 5/5 — Great App

*2018-12-19*

If you need to know relative humidity get this app.  Faster and easier to use than humidity charts.

### 5/5 — Great

*2017-01-16*

This is a great handy tool. Thankyou

## Frequently asked questions about Calculator of Air

### What is Calculator of Air?

Calculator of Air is a psychrometric calculation app used to determine humidity-related properties of moist air. It uses the Wexler–Hyland formulation for accurate results.

### What parameters can Calculator of Air calculate?

It supports calculating dry-bulb temperature, wet-bulb temperature, dew point temperature, relative humidity, humidity ratio, and enthalpy. You only need to input any two of these to get the rest.

### Does Calculator of Air support different temperature units?

Yes, Calculator of Air supports both Celsius (°C) and Fahrenheit (°F) for temperature inputs and calculations.

### What is the input range for Calculator of Air?

Temperature can be entered from -273.15 °C to 99.97 °C. Relative humidity ranges from 0% to 100%. Atmospheric pressure is fixed at standard.

### Does Calculator of Air have ads?

Yes, Calculator of Air contains advertisements.

### How does the memory function in Calculator of Air work?

The memory function allows you to store calculated values for subsequent calculations, enabling continuous air-state analysis. This is useful for complex scenarios like calculating indoor humidity based on outdoor conditions.

### What devices is Calculator of Air available on?

Calculator of Air is available for iPhone and iPod devices.

### How often is Calculator of Air updated?

The latest version is 1.2.2, last updated on March 3, 2026. This indicates a history of updates, suggesting ongoing support and potential improvements.

## Version history (last 5 releases)

### 1.2.3 — 2026-04-20

- Changed the ad banner from a Smart Banner to an Adaptive Banner.
- Fixed a layout issue that occurred on some devices.
- Updated to comply with the privacy requirements introduced in iOS 14 (IDFA and App Tracking Transparency).
- Optimized the UI for 6.5-inch displays on iPhone X and later models.
- Updated the AdMob advertising SDK.
- Improved the numerical analysis algorithms, resulting in faster calculations and accurate computation of relative humidity and dew point even at extremely low temperatures (below −150 °C / -238°F ).
- Fixed a bug in the exception handling logic.

### 1.2.2 — 2026-03-03

- Fixed a layout issue that occurred on some devices.
- Updated to comply with the privacy requirements introduced in iOS 14 (IDFA and App Tracking Transparency).
- Optimized the UI for 6.5-inch displays on iPhone X and later models.
- Updated the AdMob advertising SDK.
- Improved the numerical analysis algorithms, resulting in faster calculations and accurate computation of relative humidity and dew point even at extremely low temperatures (below −150 °C / -238°F ).
- Fixed a bug in the exception handling logic.

### 1.2.1 — 2026-03-01

- Fixed a layout issue that occurred on some devices.
- Updated to comply with the privacy requirements introduced in iOS 14 (IDFA and App Tracking Transparency).
- Optimized the UI for 6.5-inch displays on iPhone X and later models.
- Updated the AdMob advertising SDK.
- Improved the numerical analysis algorithms, resulting in faster calculations and accurate computation of relative humidity and dew point even at extremely low temperatures (below −150 °C / -238°F ).
- Fixed a bug in the exception handling logic.

### 1.2.0 — 2026-02-23

- Fixed a layout issue that occurred on some devices.
- Updated to comply with the privacy requirements introduced in iOS 14 (IDFA and App Tracking Transparency).
- Optimized the UI for 6.5-inch displays on iPhone X and later models.
- Updated the AdMob advertising SDK.
- Improved the numerical analysis algorithms, resulting in faster calculations and accurate computation of relative humidity and dew point even at extremely low temperatures (below −150 °C / -238°F ).
- Fixed a bug in the exception handling logic.

### 1.1.9 — 2026-02-10

- Fixed a bug in the ad display logic.
- Updated to comply with the privacy requirements introduced in iOS 14 (IDFA and App Tracking Transparency).
- Optimized the UI for 6.5-inch displays on iPhone X and later models.
- Updated the AdMob advertising SDK.
- Improved the numerical analysis algorithms, resulting in faster calculations and accurate computation of relative humidity and dew point even at extremely low temperatures (below −150 °C / -238°F ).
- Fixed a bug in the exception handling logic.

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## More apps by yoshihito sakagami

- [カビ・ウィルス速報！ 〜 住居の健康を増進するアプリ！](https://appshunter.io/ios/app/id1116035887)
- [HumidCalc](https://appshunter.io/ios/app/humidcalc/id1135328698)
- [エアコンde省エネ！ 〜 大阪弁と動物達の奇妙な実用アプリ！](https://appshunter.io/ios/app/de/id1151407617)
- [BLOCK BREAK 3D](https://appshunter.io/ios/app/block-break-3d/id1163062845)
- [BALLOON CRASH](https://appshunter.io/ios/app/balloon-crash/id1171400368)

All apps by yoshihito sakagami: https://appshunter.io/developer/1112518506

## Related topics

[dew point humidity calculator](https://appshunter.io/ios/topics/dew-point-humidity-calculator) · [psychrometric chart](https://appshunter.io/ios/topics/psychrometric-chart) · [dew point calculator](https://appshunter.io/ios/topics/dew-point-calculator)

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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 2026-08-20.*