Count what's affected
Modules, public interfaces, and user-facing surfaces each add to the estimated blast radius.
BLAST RADIUS CHECK
Change Impact Analyzer
Estimate the blast radius of a proposed change from how many modules, interfaces, users, and operations it touches.
- Uses your inputs in a transparent calculation
- Instant result with practical next steps
- No signup required
Planning guidance only. Validate important decisions with customer evidence and your delivery team.
YOUR INPUTS
Build your result
Complete every field. The result updates only when you choose Calculate.
How it works
Check reversibility
A change that's hard to roll back carries more risk than the same change with an easy undo path.
Get an impact score
The four inputs combine into a 0-100 impact estimate with a matching review recommendation.
Continue learning: Reviewing high-risk changes safely
Frequently asked questions
What counts as a 'public interface'?
Any API, exported function, database schema, or contract that code outside the immediate change depends on — these are the highest-impact surfaces because you may not know every consumer.
Why does reversibility matter so much?
An easily reversible change can absorb a mistake with a quick rollback. An irreversible one needs to be right before it ships, which changes how much review it deserves.
Is this a substitute for actually tracing dependencies?
No — it's a quick estimate from counts you already know, meant to decide how much review rigor to apply, not a replacement for checking the actual call sites.
How is the score calculated?
Modules, interfaces, and user surfaces each contribute capped points; irreversibility adds a fixed penalty. The total is a simple, transparent sum.
How We Compare
| Feature | MVPHub | GitHub | Linear |
|---|---|---|---|
| Instant blast-radius score | Included | Not included | Not included |
| Reversibility-aware risk weighting | Included | Not included | Not included |
| Matching review recommendation | Included | Not included | Not included |
| No dependency graph setup required | Included | Not included | Not included |
GitHub can show you a diff's affected files, but doesn't score blast radius or recommend a review approach based on reversibility. This tool turns a quick estimate into a concrete review decision.
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