Comparison

NPK Calculator vs i

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

Head to head
About

NPK Calculator

This app helps optimize fertilizer solutions for plants by calculating the correct ratios of macronutrients and micronutrients. It aims to save money, prevent nutrient imbalances, and improve nutrient uptake for healthier plant growth in hydroponics or soil.

Highlights
  • Optimizes macronutrient and micronutrient ratios
  • Database of fertilizers
  • Nutrition programs from experienced growers
  • Saves money on fertilizer solutions
  • Prevents fertilizer burns and nutrient lock-out
  • Optimizes nutrient uptake
Features
Read full description

Living beings such as plants require a proper balance, especially of nutrients, for optimal growth. Essential nutrients are necessary for basic functions, and trace nutrients for the best health. Nutrient lock-out can occur when the pH is out of balance or when there is too much of a nutrient. Even if overdosing doesn't occur, nutrients can be wasted by adding too much solution per fertilizing cycle. NPK Calculator is an app for optimizing the ratio of macronutrients and micronutrients in your fertilizer solution for use in hydroponics or soil. Our in-app database contains many simple and complex fertilizers in the market. Several nutrition programs by knowledge growers with long-term experience are available in preset tabs. -Save money on fertilizer solution (up to 50%) -Know the ratio of elements available in your solution -Prevent fertilizer burns and nutrient lock-out -Optimize nutrient uptake

About

i

This app guides users through routine operations for a specific hydroponic system. It offers growing guides, scheduling, fertilization advice, record-keeping, and troubleshooting to support daily, weekly, and periodic tasks. It's designed for owners of the TAPKIT system.

Highlights
  • Growing guides
  • Scheduling and notifications
  • Fertilization advice
  • Record keeping and analysis
  • Troubleshooting system
  • Instructional videos
  • Real-time sensor alerts
Features
Read full description

i-Droponics is your day to day escort for the routine operations in the TAPKIT. i-Droponics includes growing guides, schedule, fertilization, records and analysis and advanced trouble shooting system. i-Droponics will support your daily, weekly and periodically routine so you will never forget to seed, harvest, clean & and more. This app design for TAPKIT oweners. The i-Droponics app lets TAPKIT growers access support for their crops from their pockets 24/7.  The app provides crop advice on specific climate conditions, seeding planning, fertilizer formulae adjusted for conditions at the growing site, troubleshooting, and a library of informational FAQs.   Also included are the complete operating manual, instructional videos for each step of production, and scheduling/notifications for all daily/weekly/monthly routines. On-site sensors provide real-time alerts.

Screenshots

NPK Calculator3 screens
i4 screens

Verdict

The call

The clearest difference is price: i at Free against NPK Calculator's $2.99. i also leads on rating (5.0 vs 3.3) and iOS requirement (11.0 vs 18.5). NPK Calculator's advantage is update cadence (monthly vs every 6 months) and ratings volume (8 vs 1). 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

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

ReceptionRating · Positive reviews · Number of ratings

i holds the better App Store score, 5.0 against 3.3. That said, the two scores are not equally well evidenced: NPK Calculator has 8 ratings behind it against 1, so its average is the more settled of the two.

UpkeepUpdate frequency

NPK Calculator ships an update monthly, i every 6 months. The most recent releases landed on October 26, 2026 and October 7, 2026 respectively.

Scorecard6 real differences · 4 level
NPK Calculator versus i: the parameters behind the verdict, then further details
ParameterNPK Calculatori
Price$2.99Free — better
Rating3.3 (8 ratings)5.0 (1 ratings) — better
Positive reviews33.3% of reviews—
Number of ratings8 — better1
Update frequencyMonthly — betterEvery 6 months
AdsNoNo
In-app purchasesNoNo
MonetizationPaidFree — better
DevicesiPhone, iPadiPhone, iPad, iPod — better
Requires iOS18.511.0 — better
Further details — not scored
Size3 MB90 MB
Age rating4+4+
DeveloperAnton SimonovLinnkr Inc.

Customer experience

NPK Calculator

All ratings8 ratings
Positive50.0%
Neutral12.5%
Negative37.5%
Written reviews12 reviews
Positive33.3%
Neutral0.0%
Negative66.7%

i

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

In-app purchases

None

NPK Calculator

No in-app purchases

None

i

No in-app purchases

Questions

Is NPK Calculator free?
NPK Calculator costs $2.99, with no in-app purchases.
Is i free?
i is free to download, with no in-app purchases.
Which has better reviews, NPK Calculator or i?
i is rated higher. NPK Calculator averages 3.3 out of 5 from 8 ratings, while i averages 5.0 from 1 ratings.
Do NPK Calculator or i have ads?
Neither NPK Calculator nor i shows ads.
Which is updated more often, NPK Calculator or i?
NPK Calculator ships an update monthly, and i every 6 months. Most recently, NPK Calculator was updated on October 26, 2026 and i on October 7, 2026.

Other comparisons