Comparison

Diffraction Grating Calculator vs D4H Personnel & Training

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

Head to head
About

Diffraction Grating Calculator

Features
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Diffraction Grating Calculator is a physics/math calculator that calculates the angles of diffracted orders of monochromatic light when shone on a reflective diffraction grating. Features: - Instant calculation. - Results are copyable to other apps. - Formulas are included as reference. - 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. In optics, a diffraction grating is an optical component with a periodic structure that splits and diffracts light into several beams traveling in different directions. The emerging coloration is a form of structural coloration. The directions of these beams depend on the spacing of the grating and the wavelength of the light so that the grating acts as the dispersive element. Because of this, gratings are commonly used in monochromators and spectrometers. A diffraction grating is a material that contains a large number of parallel slits separated by a distance (d). This periodic separation of slits is usually on the order of micrometers. Because this distance is on the order of the wavelength of light, when light waves pass through the grating, the slits are able to cause constructive and destructive interference among the light waves. The waves will constructively interfere if the angle of reflection delays one of the waves by a whole wavelength. Diffraction grating equation: m * λ = a * sin(θm) Where: m: The order number of the diffracted image, m = 1,2,3 ... θ: Grating angle, in radians a: Grating Spacing, in lines per meter λ: Wavelength, in meters Thanks for your support and do visit nitrio.com for more apps for your iOS devices.

About

D4H Personnel & Training

Manage personnel, qualifications, training, and availability for your response team. This proactive system helps measure performance and engage staff to ensure a high standard of professionalism.

Highlights
  • Personnel management
  • Qualification tracking
  • Training administration
  • Attendance monitoring
  • Availability management
  • Performance measurement
  • Collaborative engagement
Features
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Over 40 exceptional features for a ready and organized response team. A highly proactive system to easily manage the administration of personnel, qualifications, training, attendance, and availability. Measure performance and collaboratively engage your personnel to reach the highest standard of professionalism.

Screenshots

Diffraction Grating Calculator4 screens
D4H Personnel & Training3 screens

Verdict

The call

The clearest difference is price: D4H Personnel & Training at Free against Diffraction Grating Calculator's $2.99. D4H Personnel & Training also leads on update cadence (every 3 weeks vs every 29 months). Diffraction Grating Calculator's advantage is iOS requirement (13 vs 15.6). On ads, in-app purchases and device support there is nothing between them.

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

CostPrice · In-app purchases · Ads · Monetization

D4H Personnel & Training is free to download; Diffraction Grating Calculator costs $2.99 up front. Neither carries in-app purchases, so what you see is what you pay.

UpkeepUpdate frequency

Diffraction Grating Calculator ships an update every 29 months, D4H Personnel & Training every 3 weeks. The most recent releases landed on May 19, 2026 and September 8, 2026 respectively.

Scorecard3 real differences · 7 level
Diffraction Grating Calculator versus D4H Personnel & Training: the parameters behind the verdict, then further details
ParameterDiffraction Grating CalculatorD4H Personnel & Training
Price$2.99Free — better
Rating—3.0 (11 ratings) — better
Positive reviews—20.0% of reviews
Number of ratings—11 — better
Update frequencyEvery 29 monthsEvery 3 weeks — better
AdsNoNo
In-app purchasesNoNo
Monetization—Free
DevicesiPhone, iPad, iPodiPhone, iPad, iPod
Requires iOS13 — better15.6
Further details — not scored
Size1 MB35 MB
Age rating4+4+
DeveloperTan Chia LingD4H Technologies Ltd

In-app purchases

None

Diffraction Grating Calculator

No in-app purchases

None

D4H Personnel & Training

No in-app purchases

Questions

Is Diffraction Grating Calculator free?
Diffraction Grating Calculator costs $2.99, with no in-app purchases.
Is D4H Personnel & Training free?
D4H Personnel & Training is free to download, with no in-app purchases.
Do Diffraction Grating Calculator or D4H Personnel & Training have ads?
Neither Diffraction Grating Calculator nor D4H Personnel & Training shows ads.
Which is updated more often, Diffraction Grating Calculator or D4H Personnel & Training?
Diffraction Grating Calculator ships an update every 29 months, and D4H Personnel & Training every 3 weeks. Most recently, Diffraction Grating Calculator was updated on May 19, 2026 and D4H Personnel & Training on September 8, 2026.

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