App Overview

Perfect OB Wheel icon

Perfect OB Wheel

Evan Schoenberg · Medical

Simple, fast, yet more thorough than any other pregnancy wheel available for the iPhone, Perfect OB Wheel is better than just a replacement for your trusty paper wheel.

$1.99 · In-app purchases

PRICE
$1.99
In-app purchases
BUSINESS MODEL
Paid
No overall Grossing estimate available
RATING
4.9
3,588 ratings · Top 5%

Evidence scope: No current overall US chart position is available. Category-chart positions shown in discovery are a separate scope. Revenue is a directional model estimate, not verified earnings.

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Build Kit

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A product spec, screen plans, and build steps for your coding agent.

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What's included17 files

A product spec, phased build plan, differentiation notes, and screen references.

  • START_HERE
  • AGENTS
  • EVIDENCE
  • SPEC
  • BUILD_PLAN
  • DIFFERENTIATION
  • skills/
  • screens/
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Illustrative example: an invoice app for independent contractors. Your kit is tailored to the app you choose; this is not its generated content.

Feature spec

Goal: Send a clear invoice after finishing a job.

  • Add a client, line items, a due date, and payment instructions.
  • Preview the total before exporting a PDF.
  • Keep an editable draft if export fails.

Screen plan

Invoice editor: Client at the top, editable line items in the middle, total and preview action at the bottom.

States: Empty draft, validation errors beside each field, exporting, and a retry action that preserves the draft.

Differentiate and validate

Hypothesis: Contractors need faster repeat invoices more than more templates.

First experiment: Test duplicating a previous job with five contractors. Watch where they hesitate before expanding the feature set.

The full kit adds a phased build plan, evidence notes, tool prompts, and implementation guidance. It is a plan for your coding agent, not a finished app.

Usage: Mechanics are fair game; never reuse the original name, branding, assets, or verbatim copy.

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Quick prompt

> SELECT BUILD PLATFORM:

Good fit for mobile-first iOS and Android prototypes with managed app scaffolding.

// RORK SYSTEM PROMPT
Rork plan preview for Perfect OB Wheel: map the core Medical workflow, choose the smallest differentiated feature set, define the data and monetization boundaries, then prototype the riskiest user journey first.
            

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Opportunities

AI-GENERATED OPPORTUNITY HYPOTHESES

These are generated suggestions, not verified review quotations. Check current App Store reviews and speak with users before treating a possible gap as a requirement.

Hypothesis 1

Introduce more customizable calculation features for users.

Assumption to check: Limited calculation options and settings

Validate with people who use this workflow before building.

Hypothesis 2

Add a comprehensive help section with FAQs and contact support.

Assumption to check: Lack of user support or FAQ

Validate with people who use this workflow before building.

Hypothesis 3

Implement offline capabilities for users without consistent internet access.

Assumption to check: No offline functionality

Validate with people who use this workflow before building.

Hypothesis 4

Offer a free trial period with in-app purchases to attract more users.

Assumption to check: Single payment model with no free trial

Validate with people who use this workflow before building.

App evidence

Original App Store material. Ratings and screenshots describe the existing app, not proof of demand for your version.

App Store description

Simple, fast, yet more thorough than any other pregnancy wheel available for the iPhone, Perfect OB Wheel is better than just a replacement for your trusty paper wheel. Here's why Perfect OB Wheel is your best choice of gestational calculator: 1) Input flexibility: Start with one of: • Last menstrual period (LMP) • Conception date • Estimated date of confinement/delivery (EDC) • Ultrasound dating: Number of weeks and days gestation as of a given date ("X Weeks"). 2) Input speed: Other wheels for the iPhone make you conform to them for entering your patient's information. Why not be able to choose based on how you are holding the phone and what else you are doing at the same time? • Use the numeric entry pad (0 3 3 0 2 0 0 8) and immediately see the results, OR • Spin the date wheel at the bottom of the screen and tap Next. 3) Thorough results: All the information you would expect from a classic wheel, plus more: • Estimated Due Date • LMP Date • Conception Date • 1st Trimester End Date • 2nd Trimester End Date • Gestational Age • Conceptional Age • Expected Fetal Length based on standard fetal growth curves • Expected Fetal Weight based on standard fetal growth curves ("How much does my baby weigh, doctor?") Results are relative to 'today' by default; this can be quickly changed to reflect any date by tapping the 'today' button and selecting a new date. 4) Accurate results: Perfect OB Wheel provides exact dates and accounts for all calendar variance, including leap years. 5) Persistence: Perfect OB Wheel remembers the date and date type you last used and restores them when launched to streamline your workflow. 6) Perfect OB Tracker upgrade: Available as an in-app purchase update, the Perfect OB Tracker lets you track any number of pregnancies, with at-a-glance due date and gestational age and one-tap access to all the data Perfect OB Wheel provides. A picture and text notes can be kept on each patient. Postpartum tracking is also available. Passcode locking is available for HIPAA compliance.

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Screenshots

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Build scope

Plan a focused first version with your coding agent. These are planning assumptions, not a delivery guarantee.

Define the first version

Choose one audience and one core workflow. Use the kit to agree on its screens, data, and acceptance criteria before building.

Set boundaries

Decide which secondary features, integrations, and platform support can wait. Your version does not need to reproduce everything in the original.

Check the hard parts

Validate external services, specialist technology, data access, and ongoing costs for your chosen scope.

SUGGESTED BUILD STACK
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BUILD KIT DIFFICULTY
Starter

From the Build Kit assessment.

A reliable timeline needs an agreed scope and a technical check. Ask your agent to estimate the phases in BUILD_PLAN.md after that review.