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.
App Overview
Navy PFA Calc
*** Updated for new December 2025 BCA/CFT changes ***
$1.99 · In-app purchases
PRICE
$1.99
In-app purchases
BUSINESS MODEL
Paid
No overall Grossing estimate available
RATING
★ 4.8
313 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.
Build your own version
Build Kit
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A product spec, screen plans, and build steps for your coding agent.
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What should your app do differently? Your note travels with the kit so your coding agent builds around your idea.
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.
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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Free quick prompt For a smaller starting point
Quick prompt
Good fit for mobile-first iOS and Android prototypes with managed app scaffolding.
// RORK SYSTEM PROMPT
Rork plan preview for Navy PFA Calc: map the core Health & Fitness 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
Allow users to customize parameters or add new fitness tests.
Assumption to check: Limited customization for fitness calculations
Validate with people who use this workflow before building.
Hypothesis 2
Implement a subscription model with additional features.
Assumption to check: Single-use purchase model limits user retention
Validate with people who use this workflow before building.
Hypothesis 3
Incorporate social sharing and challenges.
Assumption to check: No community or social features
Validate with people who use this workflow before building.
Hypothesis 4
Add history graphs and trends for user performance.
Assumption to check: Lack of progress tracking over time
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
*** Updated for new December 2025 BCA/CFT changes *** Best and most fully featured US Navy Physical Fitness Assessment(PFA) / Physical Readiness Test(PRT) / Body Composition Assessment (BCA) / Combat Fitness Test (CFT) iOS application. Highlights: - Supports all approved bikes according to latest Physical Readiness Program Newsletters, CFL Guides, and OPNAVINST 6110.1L. - Only BCA calculator that supporting measurements to the 1/4 inch with proper rounding performed per the CFL guide and OPNAV. - Only height/weight calculator that supports rounding and max allowed weight per OPNAVINST 6110.1L. - Entered values are saved for quick recalculations on each use of the app. - Full cardio option support (run/walk, row, swim and bike) - PRT goal calculator: See individual event PRT results needed to make a specific score with kCal/hour needed for bikes. - CFT goal calculator: See individual event CFT results needed to make a specific score - Full support for >5000ft users - Ability to save and view past assessment results to see trends over time Calculates: -BCA results (WHtR and BF%) -CFT Results -PRT results for all official options (including all supported bikes). -Individual event scores to make a user selected score. *** Not to be used for official BFA/PRT/CFT scoring *** *** This application is not officially endorsed or sponsored by the US Navy. ***
Written user reviews are not shown here. Check current App Store reviews >
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
React Native
Expo
Supabase
React Navigation
Zustand
BUILD KIT DIFFICULTY
Intermediate
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.
