Event Study Finance Tool
Cumulative Abnormal Return Calculator
Calculate abnormal returns and cumulative abnormal return (CAR) across an event window. Enter actual returns and expected returns for each event day, and this calculator will compute daily abnormal return, total CAR, average abnormal return, and a simple interpretation of the event impact.
Enter event window data
Use decimal percentages, such as 2.5 for 2.5% and -1.2 for -1.2%. The calculator converts each day into an abnormal return using the standard formula abnormal return = actual return − expected return, then sums the event window to produce CAR.
| Day | Actual Return (%) | Expected Return (%) | Abnormal Return (%) |
|---|---|---|---|
| Day -2 | |||
| Day -1 | |||
| Day 0 | |||
| Day +1 | |||
| Day +2 |
Formula used:
Abnormal Return (ARt) = Actual Returnt − Expected Returnt
Cumulative Abnormal Return (CAR) = Σ ARt across the full event window
Average Abnormal Return = CAR ÷ number of valid event days
Positive CAR suggests outperformance relative to expectations, while negative CAR suggests underperformance.
Abnormal Return (ARt) = Actual Returnt − Expected Returnt
Cumulative Abnormal Return (CAR) = Σ ARt across the full event window
Average Abnormal Return = CAR ÷ number of valid event days
Positive CAR suggests outperformance relative to expectations, while negative CAR suggests underperformance.
Cumulative Abnormal Return
0.00%
Average Abnormal Return
0.00%
Interpretation
Neutral
Valid Days
0
Total Actual Return
0.00%
Total Expected Return
0.00%
Window Label
—
Event label
—
Event window
—
Maximum daily abnormal return
0.00%
Minimum daily abnormal return
0.00%
Absolute CAR
0.00%
CAR is useful in event studies, but interpretation depends on model choice, benchmark construction, event-window definition, and statistical testing. This tool calculates the raw cumulative abnormal return only.
Tip: For consistent use in event studies, make sure your expected return model matches your methodology, such as market-adjusted return, mean-adjusted return, or market model expected return.
Note: This tool is for informational and educational purposes only. Results are estimates and do not constitute professional advice. By using this calculator, you agree that Waldev is not liable for any errors or damages. Always verify results with official sources.
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