What This Calculator Measures
Estimate cash reserve runway and drawdown pace using expenses, income shifts, and targets.
By combining practical inputs into a structured model, this calculator helps you move from vague estimation to clear planning actions you can execute consistently.
This calculator estimates reserve runway and drawdown pace after income shifts.
How to Use This Well
- Enter reserve balance and expenses.
- Set income and expected drop.
- Choose target months.
- Review runway and gap.
- Adjust plan as needed.
Formula Breakdown
Gap = expenses - incomeWorked Example
- $12,000 reserve with $480 gap.
- Runway = 25 months.
- Target reserve = $9,600.
Interpretation Guide
| Range | Meaning | Action |
|---|---|---|
| Above target | Strong. | Maintain buffer. |
| Near target | Steady. | Keep rebuilding. |
| Below target | Short. | Grow reserves. |
| Large gap | High drawdown. | Reduce expenses. |
Optimization Playbook
- Reduce expenses: shrink the gap.
- Increase income: extend runway.
- Rebuild monthly: set a rebuild percent.
- Review quarterly: update assumptions.
Scenario Planning
- Baseline: current income.
- Drop scenario: increase drop by 10%.
- Lower expenses: reduce by 5%.
- Decision rule: keep runway above target months.
Common Mistakes to Avoid
- Ignoring income drops.
- Underestimating expenses.
- Skipping rebuild plans.
- Not revisiting targets.
Implementation Checklist
- List core expenses.
- Estimate income drop.
- Set target months.
- Track runway monthly.
Measurement Notes
Treat this calculator as a directional planning instrument. Output quality improves when your inputs are anchored to recent real data instead of one-off assumptions.
Run multiple scenarios, document what changed, and keep the decision tied to trends, not a single result snapshot.
FAQ
What is a good reserve target?
Most plans use 3-6 months of expenses.
Should I use net or gross income?
Use net income after taxes.
What if the gap is negative?
Your income covers expenses; runway is strong.