Global Period Calculator for Surgery Global Days (2026)

A global period calculator turns a procedure code and a surgery date into the dates Medicare bundles into the surgical payment. Major procedures with 90 global days cover the day before surgery, the day of surgery and the 90 days after it. Minor procedures with 10 global days cover the day of surgery and the 10 days after. Procedures with 0 global days cover only the day of the procedure.

Enter a code and the surgery date below. The calculator reads the code's global days from the current CMS fee schedule, counts the window the way Medicare contractors do, and tells you whether a later visit falls inside it and which modifier would apply.

How to calculate a global period

CMS spells out the counting in the Medicare Claims Processing Manual, Chapter 12, §40.1. For major surgeries, contractors "count 1 day immediately before the day of surgery, the day of surgery, and the 90 days immediately following the day of surgery." For minor procedures they count the day of surgery and the listed number of days after it.

1. Find the code's global days. Look up the procedure in the current Medicare fee schedule. The calculator does this for you from the CMS release.
2. Mark the pre-op day (090 only). The day before surgery is inside the package for major procedures. Minor procedures have no pre-op day.
3. Count forward from the day after surgery. Add 90 or 10 days to the surgery date. That date is the last day of the global period.
4. Test the visit date. If a visit or procedure falls between the first and last day, decide whether it's related to the surgery. Related care is bundled; unrelated care is billed with a modifier.

Example: total knee replacement

27447 carries a 90-day global. Surgery on March 2, 2026 puts the pre-op day on March 1 and the last post-op day on May 31. Pick a visit date in the timeline to see whether it's bundled.

Example: 10-day minor procedure

An incision and drainage of a simple abscess, 10060, has a 10-day global. Surgery on January 5 ends the global period on January 15, the same example CMS uses in the manual.

Global surgery indicators

Every code in the fee schedule carries a global surgery indicator. The calculator handles the three numeric periods and explains the others.

Not sure which group a code is in? The indicator card shows the global days alongside the other payment indicators for any code.

What's included in the global surgical package

Per Chapter 12, §40.1.A, the Medicare payment for a surgery with a global period covers these services when the surgeon furnishes them, in any setting:

• Pre-op visits after the decision to operate: from the day before surgery for major procedures, and on the day of surgery for minor ones
• Intraoperative services that are a usual, necessary part of the procedure
• Complications after surgery that don't need a return to the operating room
• Post-op visits related to recovery
• Post-surgical pain management by the surgeon
• Supplies, except those specifically excluded
• Dressing changes, local incision care, and removal of sutures, staples, lines, drains, tubes, casts and splints

Not included, and billable separately: the initial evaluation that decides on a major surgery, visits for unrelated problems, treatment of the underlying condition, diagnostic tests, a clearly distinct new procedure, a return to the OR for a complication, a more extensive procedure after a less extensive one fails, and critical care unrelated to the surgery.

Modifiers during the global period

Medicare denies an E/M on the day of surgery or during the post-op period unless it carries 24, 25, 57 or FT, and denies a procedure with its own global period inside another's unless it carries 58, 78 or 79 (Chapter 12, §40.4). Work through the question below to find the one that fits.

Splitting the global package: modifiers 54, 55 and 56

When more than one practitioner shares the surgical care, each bills the same procedure code and date of surgery with the modifier for their part: 54 for the surgery, 55 for post-op management, 56 for pre-op care. Medicare pays each the share of the global amount set by the code's pre-, intra- and post-operative percentages. The surgeon billing 54 receives the combined pre-op and intraoperative shares, and post-op care billed with 55 is prorated by the days each practitioner was responsible (Chapter 12, §40.4.B).

Two updates to know, both in CMS's Global Surgery booklet (MLN907166, December 2025): modifier 54 now applies whenever a practitioner expects to provide only part of the package, including an informal, undocumented transfer of care, not only a formal written one; and HCPCS add-on code G0559 reports post-op follow-up by a practitioner who didn't perform the surgery and isn't in the surgeon's group.