Rainfall Accumulation Calculator
Enter multiple rainfall readings in inches or millimeters to instantly calculate cumulative totals, averages, and event summaries.
Add Rainfall Reading
Unit:
inches
in
Load sample data:
Total
0.00
in
Average
—
in
Max Event
—
in
Readings
0
events
Readings Log
No readings yet. Add your first entry on the left.
| # | Label | Amount | Cumulative |
|---|
Quick Reference
1 in = 25.4 mm
1 mm = 0.0394 in
Summary
Enter multiple rainfall readings in inches or millimeters to instantly calculate cumulative totals, averages, and event summaries.
How it works
- Choose your preferred unit — inches or millimeters.
- Enter a label (optional) and the rainfall amount for each reading.
- Click "Add Reading" to append it to your session log.
- The summary panel updates in real time showing total, average, max, and count.
- Use the trash icon to delete any individual entry, or "Clear All" to start fresh.
- Switch units at any time — all values convert automatically.
Use cases
- Summing daily rain gauge readings across a week or month.
- Totaling rainfall from multiple storm cells during a weather event.
- Comparing average precipitation across different time periods.
- Tracking irrigation input alongside natural rainfall for agriculture.
- Calculating total inches from a series of NOAA daily reports.
- Logging seasonal snowmelt-equivalent rainfall data.
- Verifying rain gauge sensor data against manual readings.
- Building a quick field record during storm spotting activities.
Frequently Asked Questions
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Last updated: 2026-05-23 ·
Reviewed by Nham Vu