You can reconstruct short-term rental hours after the fact. Treas. Reg. §1.469-5T(f)(4) says participation may be established "by any reasonable means" and that contemporaneous daily logs are not required. What the Tax Court will not accept is a post-event "ballpark guesstimate." The difference between a rebuild that holds and one that fails is whether each entry traces back to something outside your memory: a dated message, a booking, a receipt, a photo. This post walks through how to do that, entry by entry, and says plainly that a rebuilt log is weaker than one kept at the time.
Reconstruction is allowed; guesstimates are not
The regulation is generous on paper. It lists appointment books, calendars and narrative summaries as acceptable ways to identify "services performed over a period of time and the approximate number of hours spent." Courts have read it as permitting reconstruction from records, and have repeatedly rejected reconstruction from nothing.
The phrase that recurs in the opinions is "ballpark guesstimate." A log that assigns a standard number of hours to each stay, or a round block to each week, and cannot show where those numbers came from, is treated as an estimate made to reach a threshold rather than a record of work. The reconstructed versus contemporaneous log guide covers the standard in more detail; what follows is how two taxpayers fared under it.
What worked in Leyh and what failed in Manalo
In Leyh (T.C. Summ. Op. 2015-27), the owner of twelve long-term rentals in Austin kept a contemporaneous log with dates, activity types and hours for each day she worked. It totalled 632.5 hours, short of the 750 she needed for real estate professional status, because it omitted the drive from her home 26 to 30 miles away. During the examination she revised the log: for each day the log showed work in Austin, she added 1.5 hours of round-trip travel, bringing the total to 846. The IRS refused the additional hours. The court accepted them. Its reasons are the checklist for any rebuild: the original log was detailed and day-by-day, the Austin days were easy to identify from it, she showed the travel had not already been counted, and her testimony had "clear and crisp recall" that survived cross-examination with only minor discrepancies.
In Manalo (T.C. Summ. Op. 2012-30), the owners of two long-term rentals in California kept no time log. During the examination they produced desk calendars and a log reconstructed from the calendar notations, showing 89 and 72 hours on the two properties for one year. Over the following two years they submitted three revised versions, the last one just before trial, which raised the figures and added a new "Admin and Field" category of roughly 250 to 270 hours per year. The revisions were said to be based on emails and archived documents, but those were never introduced into evidence. The court found the revised logs "uncorroborated and unreliable," noted that the hours appeared excessive relative to the work described and that many entries did not say which property or which person they related to, and held the couple had not shown more than 100 hours in either activity.
Neither case involved a short-term rental, but the principle transfers. Leyh started from a real record and added one well-defined category from a clear rule. Manalo started from appointments, added hours in rounds, and never produced the underlying documents.
Source 1: platform message timestamps
Your hosting platform's inbox is the closest thing you have to a contemporaneous log you did not know you were keeping. Every inquiry, booking confirmation, check-in question and review reply carries a timestamp. Most platforms let you export or at least scroll and screenshot a full thread history.
Turn each exchange into an entry: date, guest or listing, what the exchange was about, and a duration that reflects reading and writing the messages, not the hours between them. A guest who asked about parking at 9:14 p.m. and got an answer at 9:22 p.m. is a ten-minute entry. Keep the screenshot.
Source 2: booking calendar for turnovers
The booking calendar tells you every checkout date, and every checkout implies a turnover. If you did the turnovers yourself, each checkout is an entry for the cleaning, restocking and inspection you performed. If a cleaner did them, the entry is the coordination and inspection you did, and the cleaner's hours belong in a separate column for the "more than anyone else" comparison.
Do not assign one standard duration to every turnover. A one-night stay and a two-week stay do not take the same time to reset, and a log that says they do reads as a formula. Where you cannot recall a specific turnover, use a conservative figure and say in the entry that it is an estimate based on your usual routine.
Sources 3 and 4: receipts, mileage, photos and location history
Hardware-store, supply and furnishing receipts are dated and often timed. Each one anchors a task: the receipt for a replacement faucet on March 3 supports an entry for buying and installing it. Bank and card statements fill gaps where the paper receipt is gone. Toll records, fuel purchases and maps history on your phone anchor trips to the property; see Does Travel Time Count Toward Material Participation? for why travel should be logged separately from the work at the destination.
Photos carry dates and, usually, locations. Before-and-after shots of a repair or the picture you sent a guest of the new keypad are dated evidence that you were there doing something specific. Phone location history confirms the days you were at the property; it cannot say what you did, so pair it with another source.
Build it entry by entry, and label it
The rebuilt log should look like a real log: one line per task with a date, property, description, duration and a note on the source. Every reconstructed entry should carry a label such as "reconstructed from platform messages" or "reconstructed from receipt dated 3/3." Manalo lost in part because the court could not tell where the numbers came from; a log that states its basis on every line answers the question before it is asked.
Never change the creation date of an entry to make it look as if it was written at the time. A log that presents reconstructed entries as contemporaneous is worse than a log that is honestly reconstructed. STR Tracker shows the date an entry was created separately from the date of the activity, and lets you attach the screenshot, receipt or photo to the entry it supports, so a backfilled entry is visibly backfilled and carries its own evidence.
A sample rebuilt week:
| Date | Task | Duration | Source |
|---|---|---|---|
| Jun 2 | Replied to inquiry about pet policy | 0h 15m | Platform thread, screenshot |
| Jun 4 | Turnover after Smith stay, restock and inspect | 2h 30m | Checkout on calendar, estimate from usual routine |
| Jun 4 | Bought and installed replacement shower head | 1h 10m | Receipt 6/4 3:12 p.m., photo |
| Jun 6 | Responded to Wi-Fi outage, reset router remotely, coordinated with ISP | 0h 45m | Platform thread, ISP chat transcript |
Common mistakes in a rebuild
- Adding hours in rounds. Each revision that raises the total invites the inference that the number, not the work, was the target.
- Citing evidence you do not produce. If the entry says "from emails," the emails must be in the file.
- Entries that do not name the property or the person who did the work.
- Standard hours multiplied by counts. Seven hours per turnover, eight hours per rented day.
- Counting availability. Time spent reachable is not time spent working.
The STR audit documentation guide lists what to keep next to the log so each entry has something behind it.
Then start logging live tomorrow
A reconstructed log for the months already gone is the best you can do for those months. It is still weaker than a log kept at the time, and a professional presenting it will say so. The stronger position is a year that is part reconstructed, clearly labelled, and part contemporaneous. Finish the rebuild, put the evidence in a folder that matches the entry dates, and then log the next guest message the day it happens. If you would rather do that from your phone than a spreadsheet, you can start a free trial.