Float Erosion Analyzer
Quantify how much float has been eroded on your schedule and assess remaining schedule resilience.
Erosion % = (Original Float − Remaining Float) / Original Float × 100Interpretation Guide
- < 30%Healthy float remaining.
- 30–70%Float eroding — investigate drivers.
- > 70%Critical — schedule fragility, recovery needed.
Example
A path with 20 days of original float now has 4 days remaining → 80% erosion = critical risk.
Real-world use cases
- Critical-path monitoring
- Construction handover risk
- Mega-project schedule resilience
Common mistakes
- Tracking only critical path while ignoring near-critical paths
Professional tips
- Trend erosion weekly; sudden jumps signal hidden delays
Frequently asked questions
Why does float erode?
Late starts, slow progress, scope additions, and dependency shifts all consume float.
What this tool does
Quantify how much float has been eroded on your schedule and assess remaining schedule resilience.
It applies the standard formula Erosion % = (Original Float − Remaining Float) / Original Float × 100 so planners, schedulers and PMOs get a defensible number they can put in front of a steering committee.
Looking for the underlying terminology? Open the PM Glossary or the PM Cheat Sheet for quick references on EVM, scheduling and risk terms.
When to use it
- Critical-path monitoring
- Construction handover risk
- Mega-project schedule resilience
Typical owners: project managers, planning engineers, project controls leads and PMO analysts running weekly or monthly performance reviews on EPC, infrastructure, IT and construction projects.
How to interpret the result
Treat the number as a signal, not a verdict. Read it together with the trend over the last 3–6 reporting periods, the critical-path status, and the risk register before you change the plan.
- Compare against the baseline, not against another project.
- Investigate the drivers behind the value before reporting it up.
- Pair it with at least one complementary KPI (cost, schedule, risk or quality).
Worked example
A path with 20 days of original float now has 4 days remaining → 80% erosion = critical risk.
In a real project review, document the inputs, the resulting value, the interpretation, and the corrective action you committed to. That audit trail is what turns a calculator output into a controls decision.
Featured in Academy articles
This calculator is referenced in the FAQs of these Academy articles — read them to understand the theory behind the numbers.
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