Unknown onset or exposure duration stays unknown.
What this tool is for
Use this when two documents or observations have reliable timestamps: an inspection and a later equipment setup, for example. The result is elapsed time between those entries. It does not establish when a fire started, when a material became wet, how long someone was exposed or whether any response met a contractual requirement.
Choose events you can attribute to a source. “I saw water at 8 am” records an observation; it does not prove the water arrived at 8 am. Keep that distinction in the event description.
Enter the time with its offset
Use the format 2026-10-05T08:00:00-06:00: date, time and the offset from UTC recorded for that event. The later event must not precede the first. If a source lacks a time zone, leave that uncertainty visible rather than assuming one, especially across a daylight-saving change or different locations.
Your two-event record
Read the result in context
| The result can show | The result cannot establish |
|---|---|
| Elapsed time between entered timestamps | The unobserved beginning of damage. |
| The event descriptions you entered | Whether a professional assessment was complete. |
| The uncertainty you recorded | A cause, liability, insurance outcome or health conclusion. |
For more than two events, keep a separate chronological log and calculate only the interval relevant to the question. Do not overwrite an earlier entry when a new document arrives; record the correction and its source.
Carry a useful question into the enquiry
After calculating, you can prepare a HAUSE enquiry with every entered field. You can edit the draft and decide whether to send it. A useful question is specific: “Can you help me understand which assessment records are needed before this wet ceiling is repaired?” The water and drying guide explains the evidence behind that decision.