Comparison

Lumen Calculator vs RabattHUD

Price, ratings, monetisation and update history for both apps, side by side β€” with what reviewers say about each.

Head to head
About

Lumen Calculator

This physics and math tool quickly converts between lumens, lux, and candelas. It provides instant calculations with copyable results and includes reference formulas. Optimized for everyday use, it supports high precision and various units.

Highlights
  • Instant calculation
  • Copyable results
  • Reference formulas
  • High precision (16 decimal places)
  • Supports various units
  • Ad-free and private
Features
Read full description

The Lumen Calculator is a physics/math calculator designed to swiftly and easily convert between lumens, lux, and candelas. Features: - Instant calculation. - Results are copyable to other apps. - Formulas included as references. - Supports up to 16 decimal places. - Supports various units for each input. - Works seamlessly on both iPhone and iPad. - Lightweight, compact app optimized for everyday use. - Ad-free and built with privacy in mind. Definitions: - Lumens: Unit of luminous flux, representing the total amount of light emitted by a source. - Lux: Measure of surface illumination, indicating how much light is received by a surface. - Candelas: SI units of luminous intensity, representing light emitted from a source in a particular direction per steradian. Note: Candelas measure the light emitted in a specific direction, while lux measures the light received per unit area. One steradian, the area of the receiving surface, is equal to the squared distance between the source and the receiver. Formulas: 1. Lumens = Candelas * Ξ© (For a specific angle) 2. Lumens = Candelas * 2Ο€ * [1 - cos(ΞΈ/2)] 3. Lux = Lumens / Area 4. Lux = Candela / DistanceΒ² Where: Ξ© = 2Ο€ * [1 - cos(ΞΈ/2)] Ξ© = 4Ο€ Thanks for your support, and please visit nitrio.com for more apps for your iOS devices.

About

RabattHUD

Features
Read full description

This discount calculator not only calculates the discount on an existing price quickly, he also comes in an extremely futuristic HUD design as is known from science fiction movies. Some elements are also animated, which makes this discount calculator even cooler. Impress your friends with this app if you look like a time traveler from the year 3,001 at the next sale in the shopping center who calculates the discount. Simply enter the discount in percent and the starting price. This App will give you the final price that you have to pay at the checkout. It also shows the money you have saved. You can also share the discount with your friends via WhatsApp etc. or save it as an image on your mobile phone. Maybe you want to print it out? Of course, the app is completely ad-free and there are no in-app purchases or subscriptions. Pay once, always use. If that's not a fair deal, we don’t know what to do :-)

Screenshots

Lumen Calculator4 screens
RabattHUD3 screens

Verdict

The call

The clearest difference is price: RabattHUD at Free against Lumen Calculator's $2.99. RabattHUD also leads on update cadence (every 2 months vs every 27 months). On ads, in-app purchases, device support and iOS requirement there is nothing between them.

Scored on Price Β· Rating Β· Positive reviews Β· Number of ratings Β· Update frequency Β· Ads Β· In-app purchases Β· Monetization Β· Best chart rank Β· Devices Β· Requires iOS

CostPrice Β· In-app purchases Β· Ads Β· Monetization

RabattHUD is free to download; Lumen Calculator costs $2.99 up front. Neither carries in-app purchases, so what you see is what you pay.

UpkeepUpdate frequency

Lumen Calculator ships an update every 27 months, RabattHUD every 2 months. The most recent releases landed on August 22, 2026 and June 10, 2026 respectively.

Scorecard2 real differences Β· 6 level
Lumen Calculator versus RabattHUD: the parameters behind the verdict, then further details
ParameterLumen CalculatorRabattHUD
Price$2.99Free β€” better
Positive reviews0.0% of reviewsβ€”
Update frequencyEvery 27 monthsEvery 2 months β€” better
AdsNoNo
In-app purchasesNoNo
MonetizationPaidβ€”
DevicesiPhone, iPad, iPodiPhone, iPad, iPod
Requires iOS13 β€” better13.2
Further details β€” not scored
Size1 MB1 MB
Age rating4+4+
DeveloperNitrioMarc Martin

In-app purchases

None

Lumen Calculator

No in-app purchases

None

RabattHUD

No in-app purchases

Questions

Is Lumen Calculator free?
Lumen Calculator costs $2.99, with no in-app purchases.
Is RabattHUD free?
RabattHUD is free to download, with no in-app purchases.
Do Lumen Calculator or RabattHUD have ads?
Neither Lumen Calculator nor RabattHUD shows ads.
Which is updated more often, Lumen Calculator or RabattHUD?
Lumen Calculator ships an update every 27 months, and RabattHUD every 2 months. Most recently, Lumen Calculator was updated on August 22, 2026 and RabattHUD on June 10, 2026.

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