Comparison

100cm Ruler vs Rainfall Calculator

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

Head to head
About

100cm Ruler

This app provides a digital ruler for measuring the length and diameter of small objects directly on your device. It features a millimeter scale and allows for easy sliding to measure.

Highlights
  • Digital ruler functionality
  • Millimeter scale
  • Diameter measurement
  • Screen sliding for measurement
  • Ad removal option
Features
Read full description

Plotting scale is useful to measure the length of small articles and insects. Squared in millimeters on the lower left, thus the diameter can be measured roughly. Hold the screen and slide your iPhone to the right. https://www.youtube.com/watch?v=kxU9xi88IiY Ads can be removed on "Info page".

About

Rainfall Calculator

Calculate potential rainwater harvest volume and cost savings. This tool helps determine annual water collection capacity based on rainfall and roof area, recommending optimal tank sizes for efficient water storage. It also allows for cost-saving analysis by comparing harvested water to mains water prices.

Highlights
  • Instant rainwater calculation
  • Cost savings evaluation
  • Minimum tank size recommendation
  • Supports various input units
  • Formula references included
  • Results copyable to other apps
Features
Read full description

The Rainfall Calculator is a physics/math tool designed to help you determine how many liters/gallons of rainwater you can harvest per year, evaluate cost savings, and recommend the minimum tank size for water storage. Features: - Instant calculation. - Results can be copied to other apps. - Includes formula 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. Rainwater Collection Calculator: - The catchment area is multiplied by the depth of rain that falls on it to give the total volume of water produced. - 1 millimeter of rain over 1 square meter of roof equals 1 liter of water. - Annual rainfall (in millimeters) x Roof surface area (in square meters) = Roof catchment capacity. - You can add the cost of mains or tap water per m³ to evaluate the annual cost savings if this rainwater is collected and used instead of drinking water. - The minimum tank size should store 33% of the "Annual Rainfall On Your Roof Area" as you will use the water while you are collecting it. The rain will collect in gutters that channel the water into downspouts and then into some sort of storage vessel. Rainwater collection systems can be as simple as collecting rain in a rain barrel or as elaborate as harvesting rainwater into large cisterns to supply your entire household demand. You can also collect rainwater for garden use. Plants prefer rainwater because it's naturally soft and free of chlorine and other chemicals. If drought is a problem where you live, collecting rainwater is a good way to handle watering restrictions. If you're on a municipal water system, you can save a considerable amount of money. Thank you for your support! Visit nitrio.com for more apps for your iOS devices.

Screenshots

100cm Ruler3 screens
Rainfall Calculator4 screens

Verdict

The call

The clearest difference is price: 100cm Ruler at Free against Rainfall Calculator's $2.99. 100cm Ruler also leads on update cadence (every 3 months vs every 29 months). Rainfall Calculator's advantage is rating (5.0 vs 4.0) and in-app purchases (none vs 1). On ratings volume, ads, device support and iOS requirement 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

100cm Ruler is free to download; Rainfall Calculator costs $2.99 up front. 100cm Ruler sells 1 one-off in-app purchase. Rainfall Calculator asks for nothing beyond the download.

ReceptionRating · Positive reviews · Number of ratings

Rainfall Calculator holds the better App Store score, 5.0 against 4.0. Both are backed by a comparable volume of ratings — 1 and 1 respectively.

UpkeepUpdate frequency

100cm Ruler ships an update every 3 months, Rainfall Calculator every 29 months. The most recent releases landed on October 1, 2026 and September 28, 2026 respectively.

Scorecard5 real differences · 5 level
100cm Ruler versus Rainfall Calculator: the parameters behind the verdict, then further details
Parameter100cm RulerRainfall Calculator
PriceFree — better$2.99
Rating4.0 (1 ratings)5.0 (1 ratings) — better
Positive reviews45.1% of reviews—
Number of ratings11
Update frequencyEvery 3 months — betterEvery 29 months
AdsNoNo
In-app purchasesYesNo — better
MonetizationFree with in-app purchases — betterPaid
DevicesiPhone, iPodiPhone, iPad, iPod — better
Requires iOS12.0 — better13
Further details — not scored
Size62 MB1 MB
Age rating4+4+
DeveloperZOOMO Inc.Nitrio

Customer experience

100cm Ruler

All ratings1 ratings
Positive100.0%
Neutral0.0%
Negative0.0%
Written reviews51 reviews
Positive45.1%
Neutral13.7%
Negative41.2%

Rainfall Calculator

All ratings1 ratings
Positive100.0%
Neutral0.0%
Negative0.0%

In-app purchases

1 purchases

100cm Ruler

One-time1
  • Remove ADS$1.99
None

Rainfall Calculator

No in-app purchases

Questions

Is 100cm Ruler free?
100cm Ruler is free to download, with in-app purchases available.
Is Rainfall Calculator free?
Rainfall Calculator costs $2.99, with no in-app purchases.
Which has better reviews, 100cm Ruler or Rainfall Calculator?
Rainfall Calculator is rated higher. 100cm Ruler averages 4.0 out of 5 from 1 ratings, while Rainfall Calculator averages 5.0 from 1 ratings.
Do 100cm Ruler or Rainfall Calculator have ads?
Neither 100cm Ruler nor Rainfall Calculator shows ads.
Which is updated more often, 100cm Ruler or Rainfall Calculator?
100cm Ruler ships an update every 3 months, and Rainfall Calculator every 29 months. Most recently, 100cm Ruler was updated on October 1, 2026 and Rainfall Calculator on September 28, 2026.

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