Comparison

Codon One vs Day Genius

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

Head to head
About

Codon One

Master molecular biology, genetics, evolution, and life chemistry through interactive modules and quizzes. Explore essential concepts with clear diagrams and concise explanations. Includes helpful tools for sequence analysis and genetic code reference.

Highlights
  • Interactive learning modules
  • Quick quizzes for comprehension
  • Clear diagrams and plain language
  • Molecule reference guide
  • Sequence analysis tools
  • Genetic code exploration
Features
Read full description

Codon One helps you learn biology step by step, with short lessons, quick quizzes, flashcards, and a searchable glossary. Build a solid foundation in molecular biology, genetics, evolution, cell biology, development, and the history of science. Each section breaks complex ideas into clear explanations, diagrams, and focused checks for understanding. Core course (Modules) Module 1: Chemistry of Life – atoms & elements, bonds, water, pH, biomolecules Module 2: Genetics – chromosomes, replication, transcription, translation, regulation Module 3: Evolution – history of life, phylogeny, selection, drift, speciation, molecular evolution Module 4: History of Science – ideas, methods, and experiments that shaped modern biology Module 5: Cell Biology – membranes & transport, organelles & energy, cytoskeleton, signaling, cell division Module 6: Development – fertilization & body plans, differentiation, pattern formation & morphogenesis, growth & repair, evo-devo Additional topics are planned for future updates, including Animal Physiology, Microbiology & Immunology, Plant Biology, and more. Glossary & Flashcards Look up the essentials in one place - key terms from every module, plus the 20 amino acids and the nucleobases. Turn any topic into a flashcard deck and review with smart, spaced practice that focuses on the cards you find hardest. Quiz & Progress Practice across biochemistry, genetics, evolution, cell biology, development, and science history in a dedicated quiz area. Track improvement with success rates and per-topic stats, and let the app resurface your weak questions for targeted review. Keep a daily streak going to build a steady habit. Got a good question? Submit it directly from the app. Built-in Tools Sequence Operator: paste DNA, reverse or complement it, transcribe to RNA, translate in all six reading frames, and view length, GC content, and melting temperature. Codon Picker: explore the genetic code, see which codons map to each amino acid or stop signal, and tweak bases to see the effect. Triplet Encoder: write a message in amino-acid single-letter code and encode it as a DNA triplet sequence, then decode it by translation. Found a bug or have suggestions? Email info@codon-one.com - we read every message.

About

Day Genius

Learn to calculate the weekday for any date without a calendar or phone. This app teaches a step-by-step method with interactive drills and games to master the skill. Unlock advanced features with a one-time purchase.

Highlights
  • Step-by-step weekday calculation method
  • Interactive drills and flashcards
  • Two engaging practice games
  • Progress tracking and weak-spot identification
  • Reference tables for calculations
  • Support for historical calendar rules
Features
Read full description

July 20, 1969? Sunday. July 4, 1776? Thursday. Your birthday? Work it out in your head, no calendar, no phone. It looks like a party trick. It's a method, and Day Genius teaches it one small step at a time. HOW IT WORKS Every month has a code. Add it to the day of the month and a code for the year, then take out the sevens. What's left is the weekday. 1. Day numbers — 0 = Sunday through 6 = Saturday 2. Take out the sevens — turn any total into a day number 3. Month codes — twelve values, each with a memory hook 4. Combine & find the weekday — your first real answer 5. Year code — turn any year into its code 6. Leap-year rule — a small fix for January and February 7. Century shift — any century, not just your own 8. Full date — everything together, on real dates Master a step with three drills at 90% or better and the next one opens. The first four steps are free; a one-time purchase, not a subscription, unlocks steps 5–8. THE MONTH CODES YOU ALREADY KNOW Learned month codes as January = 6? Keep them. The Month codes step offers the classic list (January = 0, the default) or the alternate list, every code one lower, with twelve memory hooks of its own. Year codes come matched, and every lesson, check, flashcard, drill, game, Reference table and widget follows your choice. Switch anytime. THREE WAYS TO PRACTICE Check yourself — untimed questions that show the reasoning, let you pick again, and record nothing. Flashcards — a deck for every step. Tap to flip, retire what sticks, and the rest come back around. Full date adds Famous dates: twelve dates from 1776 to 2001, with what happened on the back. Drills — timed and recorded, with no time limit: the path to mastery. DRILLS THAT FIND YOUR WEAK SPOTS Day Genius notices the months, years and centuries you miss or answer slowly, and mixes them back into later drills. Progress shows mastery, streak, speed trend and skill breakdown, plus a one-tap weak-spot drill and an optional daily reminder. TWO GAMES Speed Round — ten random dates against the clock, with a full breakdown afterward. Date Drop — dates fall, and you drag each into its weekday bucket before it lands. Catch them early for bonus points and in a row for combos. CORRECT BACK TO YEAR 1 Day Genius follows the calendar Britain and its colonies actually used. They skipped September 3–13, 1752, and before that every fourth year was a leap year, century years included. The Before 1752 bonus lesson shows how to work out older dates; countries that switched at other times can differ. An independent algorithm cross-checks the engine across thousands of dates. THE REFERENCE Every table behind the method, each opening as you master its step; tables for steps 5–8 also need the unlock. Check any date is open from the first launch: pick a date and it names the weekday. Unlock and master the Year code step, and it shows the full calculation too. Pick the 1900s or the 2000s as your home century, and the tables, examples and drills follow it. WIDGETS Date of the Day hands you a fresh date to solve, Code Cards keeps a code in front of you, and Practice Streak keeps the chain going. The last two fit the Lock Screen too. BUILT TO BE READ AND HEARD VoiceOver support throughout, and Dynamic Type including the accessibility sizes. With VoiceOver or Reduce Motion on, Date Drop switches to a calm, button-based mode: no falling, no dragging. FREE TO START, ONE PURCHASE FOR THE REST The first four steps are free, decks and checks included, and they're enough to find a weekday once you're given the year code. A one-time purchase, not a subscription, unlocks steps 5–8 and their decks, Famous dates included. Both games, the Before 1752 bonus lesson and the rest of the Reference open with it as you master the steps they use. PRIVATE BY DESIGN No account. No ads. No personal data collected. Your progress stays on your device, and purchases are handled by Apple.

Screenshots

Codon One4 screens
Day Genius4 screens

Verdict

The call

The clearest difference is rating: Day Genius at 5.0 against Codon One's 4.5. Day Genius also leads on review sentiment (100% vs 76%). Codon One's advantage is ratings volume (25 vs 1) and iOS requirement (15.6 vs 26.0). On price, update cadence, ads and in-app purchases 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

Both are free to download. Codon One sells 7 one-off in-app purchases and Day Genius sells 1 one-off in-app purchase. Whichever you choose, the download price is not the number that matters.

ReceptionRating · Positive reviews · Number of ratings

Day Genius holds the better App Store score, 5.0 against 4.5. That said, the two scores are not equally well evidenced: Codon One has 25 ratings behind it against 1, so its average is the more settled of the two. Written reviews point the same way: 76% of Codon One's written reviews are positive against 100% of Day Genius's.

UpkeepUpdate frequency

Codon One ships an update every 3 weeks, Day Genius every 2 weeks. The most recent releases landed on October 29, 2026 and October 14, 2026 respectively.

Scorecard4 real differences · 6 level
Codon One versus Day Genius: the parameters behind the verdict, then further details
ParameterCodon OneDay Genius
PriceFreeFree
Rating4.5 (25 ratings)5.0 (1 ratings) — better
Positive reviews76.5% of reviews100.0% of reviews — better
Number of ratings25 — better1
Update frequencyEvery 3 weeksEvery 2 weeks — better
AdsNoNo
In-app purchasesYesYes
MonetizationFree with in-app purchasesFree with in-app purchases
DevicesiPhone, iPad, iPod — betteriPhone, iPad
Requires iOS15.6 — better26.0
Further details — not scored
Size277 MB6 MB
Age rating4+4+
DeveloperDaniel GebertCraig Ricks

Customer experience

Codon One

All ratings25 ratings
Positive84.0%
Neutral8.0%
Negative8.0%
Written reviews17 reviews
Positive76.5%
Neutral0.0%
Negative23.5%

Day Genius

All ratings1 ratings
Positive100.0%
Neutral0.0%
Negative0.0%
Written reviews1 reviews
Positive100.0%
Neutral0.0%
Negative0.0%

In-app purchases

7 purchases

Codon One

One-time7
  • Module 2: GeneticsFree
  • Module 1: Chemistry of LifeFree
  • Module 3: Evolution$2.99
Show 4 more
  • Module 4: Science History$2.99
  • Module 5: Cell Biology$2.99
  • Module 6: Development$2.99
  • Unlock All$8.99
1 purchases

Day Genius

One-time1
  • Full Method$3.99

Questions

Is Codon One free?
Codon One is free to download, with in-app purchases available.
Is Day Genius free?
Day Genius is free to download, with in-app purchases available.
Which has better reviews, Codon One or Day Genius?
Day Genius is rated higher. Codon One averages 4.5 out of 5 from 25 ratings, while Day Genius averages 5.0 from 1 ratings.
Do Codon One or Day Genius have ads?
Neither Codon One nor Day Genius shows ads.
Which is updated more often, Codon One or Day Genius?
Codon One ships an update every 3 weeks, and Day Genius every 2 weeks. Most recently, Codon One was updated on October 29, 2026 and Day Genius on October 14, 2026.

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