Free Duplicate Timecard Entry Checker: Overlapping Shifts

Page last updated 25 Oct 2026

How to use the duplicate timecard entry checker

Choose the layout of your data: date with start and end, start and end date-times, or one row per punch.
Paste the rows or load a CSV, and confirm the columns. Results appear as you type.
Tick the fields that must match for an exact duplicate, and set the near-duplicate window in minutes.
Review each flagged row at its source, correct it there, re-export, and run the check again until it is clean.

How does the checker flag a row?

Entries are grouped by employee. Two entries are exact duplicates when every field you tick matches, possible duplicates when their start and end fall within a few minutes of each other, and overlaps when each starts before the other ends, with an end earlier than its start read as the next day. Back-to-back entries and split shifts are not flagged. Punch lists are sorted by time and must alternate IN and OUT.

For example, the shifts sample has 12 entries for 6 employees. The checker finds 1 exact duplicate, 1 possible duplicate (8:00-16:00 and 8:02-16:01), 1 entry inside another and 2 that overlap, including an overnight shift that runs into the next morning. It leaves a split shift and separate shifts alone, and reports 18.47 hours that would be counted twice if every row were paid. The names and times are made up; yours come from what you load.

Who should use the duplicate timecard entry checker

Payroll staff cleaning timekeeping data before a pay run
Managers who suspect an import ran twice or a punch was added by two people
Anyone who wants to see how many hours would be paid twice

Who should not use this

Anyone who wants overtime or pay calculated; this finds data errors, not pay
Anyone who needs rounding, break policy or rate checks
Anyone expecting the checker to decide what is true; it flags rows and you decide

Limitations

It does not read .xlsx files; paste the cells or save as CSV.
Entries for different pay codes may need a different layout than the one the checker assumes.
It cannot tell a legitimate overlap, such as paid on-call time, from an error.
Do not delete a row only because it was flagged.
Nothing is uploaded or stored on a server. Clearing your browser data also removes the saved profile.

Check a timesheet for duplicate entries

Use it as a duplicate timesheet entry checker, to detect duplicate time entries and overlapping employee shifts in a pasted table or CSV. Choose the layout of your data, confirm the columns, and the results appear as you type. Try the sample (sample files can be downloaded under the calculator).

Three layouts: date + start + end, start and end date-time, or one row per punch.
Works with pasted Excel cells or a CSV.
Row numbers match your data, so you can find each row.

Detect duplicate punches and overlapping shifts

The checker looks for four different kinds of problem in a timesheet or a list of clock punches, and it labels each flagged row with the reason:

Exact duplicates: same employee, same chosen fields.
Overlaps: the same employee's times intersect, with the overlap in minutes, including shifts that cross midnight.
Possible duplicates: start and end within a few minutes of each other.
Punch problems: repeated, missing, zero-length and very long.

Exact duplicates vs possible conflicts

Exact duplicates vs possible conflicts
Case	Example	Flagged?
Exact duplicate	08:00-16:30 entered twice	Yes, exact
Possible duplicate	08:00-16:00 and 08:02-16:01	Yes, if the window is on
Overlap	08:00-12:00 and 11:00-15:00	Yes, 60 minutes
Inside another entry	08:00-16:00 and 10:00-11:00	Yes
Back-to-back	08:00-12:00 and 12:00-16:00	No
Split shift	08:00-12:00 and 13:00-17:00	No

How the checker flags rows

Entries are grouped by employee (names are compared without regard to capital letters). An end time earlier than the start is read as the next day, so 22:00-06:00 works. Any pair whose time ranges intersect is checked against the rules in the table above. It also adds up the hours that would be counted twice if every row were paid.

Example of a duplicate shift

The shift sample has 12 entries for 6 employees. The checker finds 1 exact duplicate (Ana Ruiz, 8:00-16:30 entered twice), 1 possible duplicate (Eli Moss, 8:00-16:00 and 8:02-16:01), 1 entry inside another (Fay Lund) and 2 overlap (Dev Patel's overnight shift runs into the next morning's entry), and correctly leaves alone Ben Cole's separate shifts and Cara Doyle's split shift. 18.47 hours would be counted twice if every row were paid.

Fixing timecard errors before payroll

Look at the original source (clock, app, schedule) for each flagged row.
If an entry is truly a repeat, remove or void it in the source system rather than editing the export.
If hours really were worked in both entries, correct the times so they no longer overlap.
Ask the employee or manager when it is unclear. Never change a time record without a note of who changed it and why.
Re-export and run the checker again until it is clean.

Sources and review

Reviewed on 25 Oct 2026 against the published sources below. Rules and prices change, so check the current position before you rely on a figure.

Common questions

How do I find duplicate entries in a timesheet?

Paste the rows into the checker above. It groups entries by employee and the fields you choose (date, start, end, an extra column such as job) and lists every group with more than one entry, with row numbers. It also lists overlapping times, which a plain duplicate finder misses.

What causes duplicate timecard entries?

A time-clock import run twice, a manager adding a missed punch while the employee also corrects it, a double tap on a clock or app, a sync that retried, a week copied and pasted twice, or moving data between two systems.

How do I check if two shifts overlap?

For the same employee, two entries overlap when each one starts before the other ends: start of A is before end of B, and start of B is before end of A. Entries that merely touch (one ends at 12:00, the next starts at 12:00) do not overlap. The tool applies this rule, including shifts that run past midnight.

How do I find duplicate rows in Excel?

Select the data and use Data, Remove Duplicates, or Home, Conditional Formatting, Highlight Cells Rules, Duplicate Values. Those find identical rows only. To find overlapping times in Excel, with employee in column A, start date-time in B and end date-time in C, put this in D2 and fill down: =COUNTIFS($A:$A,A2,$B:$B,"<"&C2,$C:$C,">"&B2)>1. TRUE means the row overlaps another row (the row always counts itself once).

Can two shifts overlap on a timesheet?

For one employee, two entries covering the same clock time cannot both be hours worked in one place, so the overlap usually means the same time was entered twice or an old row was not removed. Check before paying: a genuine split shift has a gap between the parts, and entries for different pay codes may need a different layout. If both rows are paid, the overlapping hours are counted twice.

How do I detect duplicate clock-in or clock-out punches?

Switch to the punch layout. For each employee the punches are sorted by time and expected to alternate IN, OUT, IN, OUT. A second punch of the same kind within a few minutes is a repeated punch; an IN followed by another IN is a missing OUT; an OUT with no IN is a missing IN; and a very long shift usually means a missing punch.

How do I clean timekeeping data before payroll?

Remove or correct exact duplicates, resolve overlaps, fix missing punches, re-export, then run the checker again until it comes back clean. Keep the original records and note who changed what and why.

Is this a timecard anomaly checker?

It checks the anomalies that cause double-counted hours: exact duplicates, overlapping entries, and punch sequences that do not alternate IN and OUT. It is a time entry validation tool for those problems, not a check of pay rates, breaks policy or overtime.

What is duplicate punch detection?

Duplicate punch detection finds the same clock event recorded more than once, for example two IN punches a minute apart. This tool compares each punch with the previous one for the same employee and flags a repeat within the window you set.

How do I identify overlapping clock in and clock out times?

List each employee's shifts by start time and check whether a shift starts before the previous one ends. The checker does this for you, including shifts across midnight, and acts as a timesheet overlap detector and timekeeping data quality checker you can run before every payroll.

Does the checker flag split shifts?

No. A split shift (for example 8:00-12:00 and 13:00-17:00) has a gap between the parts, and back-to-back entries that touch are not overlapping. Only entries whose times actually intersect are flagged.

Can I choose what counts as a duplicate?

Yes. Tick the fields that must match: date, start, end and an extra column such as job or location. Two entries with the same times but a different job are an exact duplicate only if you do not tick the extra column.

Is it safe to upload payroll CSV data to an online tool?

With this tool nothing is uploaded: the file is read and compared in your browser and the code makes no network request with your data (you can confirm in the Network tab of your browser's developer tools). That is a statement about this tool only. Many other online tools do send files to a server, so check each one's privacy policy before you use real payroll data. Never paste Social Security numbers or bank details into any comparison tool; employee IDs and hours are enough.

Guides that explain the rules

Related tools

This tool produces a document from the information you type. It does not give legal, tax or accounting advice, and it does not check that your figures or rates are right. See the disclaimer. Found a mistake? Report an error in a calculation.