Обновлено 9 октября 2026 г.

What a Contemporaneous Day Log Looks Like, and Why the Timing Matters

A contemporaneous day count log is a record made at or near the time each day happened, one entry per day, saying where you were. This guide covers the fields each entry needs, how to handle travel days and corrections, what backs a log up, and why the record has to exist before anyone asks for it. Neither Publication 570 nor the regulation prescribes a log format, so we mark clearly where the published guidance stops.

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Rows of archive boxes and binders on metal shelves along a narrow aisle, suggesting records kept in order

What is a contemporaneous day count log?

A contemporaneous day count log is a record made at or near the time each day happened, with one entry per day saying where you were. It is not a summary built from memory when someone asks.

The presence test is counted in days. Under 26 CFR 1.937-1(c)(1), you meet it if you satisfy any one of five conditions, and Publication 570 lists the same five. One of them is the 183 day rule. Every one of them turns on how many days you were in Puerto Rico or in the United States. A log is how you keep that count.

What does contemporaneous mean for a day log?

Contemporaneous means the entry was made when the day happened or shortly after, not rebuilt later. The word carries a lot of weight in any talk about records, so be exact about what the sources say and where they go quiet.

Neither the regulation nor Publication 570 defines the word, and neither prescribes a log format for ordinary presence days. Published guidance does not address this directly. If your year turns on how a reviewer weighs a particular record, get it in writing from a licensed tax professional before you file.

What the sources do give you is the unit you are counting. A day counts toward Puerto Rico if you are physically present there at any time during the day. That single rule tells you what an entry has to capture.

What belongs in each daily entry?

Each entry needs the date, where you were, and enough detail to settle the days that are not obvious. A short entry you actually write beats a thorough one you skip.

The date and the location

Record the calendar date and where you were that day: Puerto Rico, the United States, or somewhere else. The regulation counts a day as a Puerto Rico day if you are physically present there at any time during it, so one line per day is enough for an ordinary day at home.

Travel days and split days

Travel days are where logs fail. If you were in both places on one day, the regulation and Publication 570 both say the day counts toward the possession. The longer discussion is in what counts as a day in Puerto Rico, and the open questions are in present in both places on the same calendar day. For the log, write down both places and roughly when you crossed. Sort out the treatment later. The facts are the part you can't recover.

Days that count for a stated reason

Some days outside Puerto Rico can still count. The regulation names days spent outside the possession for qualifying medical treatment, days during a Presidentially declared major disaster period, and days under a mandatory evacuation order. For medical treatment, Publication 570 says you must prepare or obtain and maintain supporting documentation, and produce it within 30 days if the IRS or the territory's tax administrator asks. In the entry, note the reason and where the paperwork is kept.

When the entry was made

Add a field for the date you wrote the entry. It takes a few seconds, and it makes the log's timing visible to anyone else who reads it. If the date field is missing, nobody can tell an entry made on the day from one made a year later.

What is a log entry edited a year later worth?

An entry edited a year later is a different kind of record from one made on the day, and the sources we read do not say how much weight it carries. Published guidance stops there, so treat the question as unsettled and ask your advisor.

What you can do is keep the difference visible. Three things are worth separating:

The original entry, left as written, with the date it was made.
A dated correction, added as a new line that says what changed and when you noticed.
A rebuilt record, reconstructed from a calendar, photos or receipts after the fact, and labeled as rebuilt.

Do not overwrite the original and do not backdate. A rebuilt record is better than no record, and it is easy to tell apart from entries made on the day. An overwritten entry that looks original is the version that damages your credibility if anyone checks.

What backs up the log?

The log is your statement of where you were. Other records corroborate it, and the log should point to them. Boarding passes and airline records fix the travel days. Receipts, lease and utility records, and medical paperwork cover the rest.

The simplest habit is a reference field on each entry: a confirmation number, a receipt date, a folder name. The log then tells a reviewer where to look instead of asking them to take your word for it. The wider picture of what to keep is in documenting your presence for an audit.

Why does the record have to exist before anyone asks?

The general rule is that records must be sufficient to establish the items on your return, kept available for inspection, and retained as long as their contents may become material to any internal revenue law. Section 1.6001-1(a) requires permanent books or records sufficient to establish the amount of gross income, deductions, credits, or other matters required to be shown on a return. Paragraph (e) requires that they be kept at all times available for inspection and retained as long as they may be material.

That is a standing duty, not a duty that starts with a request. The one place the sources show a clock is the medical treatment documentation, which must be produced within 30 days of a request. A record that has to be created after the request arrives is a record you are late on.

This is the recordkeeping problem One83 was built for: an automatic day ledger is what the app keeps for you, so the entry exists on the day instead of at tax time.

What should you do from here?

Write one dated entry per day, mark the date you wrote it, record both places on split days, and point each entry at the record that backs it. Record corrections as corrections. For the standard that applies to your year, ask a licensed tax professional.

Frequently Asked Questions

Does the IRS require a day log for the presence test?

The sources read for this article set no specific log format for ordinary presence days. The general duty in 26 CFR 1.6001-1 is to keep records sufficient to establish items on the return, and a log is how most people meet that in practice. Confirm the standard for your year with your advisor.