Skip to main content

How Long Does It Take to Understand a New Codebase?

Quick Answer​

Average time to understand a new codebase: 2-4 weeks.

But "understand" means different things at different levels:

LevelDescriptionTimeline
NavigationCan find things1-3 days
ComprehensionUnderstand what code does1-2 weeks
ContextUnderstand why it was built this way2-4 weeks
MasteryCan change it confidently1-3 months

Timeline by Codebase Size​

Codebase SizeNavigationContributionMastery
Small (under 10k lines)Hours1-3 days1-2 weeks
Medium (10k-100k lines)1-3 days1-2 weeks1-2 months
Large (100k-500k lines)1-2 weeks2-4 weeks3-6 months
Massive (500k+ lines)2-4 weeks1-2 months6-12 months

What Affects Understanding Time​

Makes It Faster​

FactorTime Reduction
Good documentation-30%
Consistent patterns-25%
Strong typing (TypeScript, etc.)-20%
Comprehensive tests-20%
Familiar technology-30-40%
AI assistance (Ramp)-40-50%

Makes It Slower​

FactorTime Increase
No documentation+50%
Inconsistent patterns+40%
Legacy/technical debt+50%
Unfamiliar technology+40%
High tribal knowledge+60%
Poor naming+30%

Stages of Codebase Understanding​

Stage 1: Lost (Day 1-2)​

What it feels like:

  • Opening random files
  • Not understanding folder structure
  • Getting lost following imports
  • Everything looks foreign

This is normal. Don't panic.

Stage 2: Navigation (Days 3-7)​

What it feels like:

  • Can find files by searching
  • Understand general folder purpose
  • Can trace simple code paths
  • Starting to see patterns

Stage 3: Comprehension (Week 2)​

What it feels like:

  • Understand major components
  • Can explain how features work
  • Know where to look for things
  • Can make targeted changes

Stage 4: Context (Weeks 2-4)​

What it feels like:

  • Understand historical decisions
  • Know why "weird" code exists
  • Can predict side effects
  • Comfortable in most areas

Stage 5: Mastery (Month 1-3)​

What it feels like:

  • Can refactor confidently
  • Understand edge cases
  • Propose architectural changes
  • Guide others through the codebase

Research Findings​

FindingSource
Top 3 barriers: new technology, poor docs, finding expertiseGoogle Engineering Survey
Developers spend 75% of time understanding code, 25% writingIEEE Study
Good code structure can reduce comprehension time by 50%Software Engineering Research

How to Accelerate Understanding​

Day 1​

  1. Run the application — See it work before reading code
  2. Scan folder structure — Get the lay of the land
  3. Find entry points — Where does execution start?
  4. Ask for architecture overview — Get the big picture

Week 1​

  1. Trace one request end-to-end — Build a mental model
  2. Read the data models — Understand what entities exist
  3. Ask questions constantly — Use Ramp or teammates
  4. Make small changes — Learn by doing

Week 2+​

  1. Map the architecture — Draw diagrams
  2. Read git history — Understand the why
  3. Review PRs — Learn from team patterns
  4. Document what you learn — Help future you (and others)

Common Questions​

"How do I know when I understand it?"​

You understand the codebase when you can:

  • Explain the architecture to someone new
  • Estimate how long changes will take
  • Know which person to ask for which area
  • Make changes without unexpected breakage

"What if the codebase is a mess?"​

Legacy codebases take longer. Focus on:

  1. The parts you need for your current task
  2. Patterns rather than understanding everything
  3. Who knows what (tribal knowledge mapping)

"Should I read all the documentation first?"​

No. Documentation is often outdated. Use this order:

  1. Run the code
  2. Trace a flow
  3. Ask questions
  4. Check docs for reference

Using Ramp for Codebase Understanding​

# Get AI-generated overview
ramp explore

# Ask questions as you explore
ramp voice
> "What does this module do?"
> "How does data flow from X to Y?"
> "Why was it built this way?"

# Generate onboarding documentation
ramp guide

Facing a new codebase? Try Ramp free →