Disclaimer: This tool relies on user-input times. Always double-check calculations and follow safety protocols for implants. Use at your own risk.
MRI Active Scan Time Calculator / Countdown
Click the button above to expand instructions.
- Enter Operator Name – Start by typing in the operator’s name.
- Set Allowed Active Scan Time – Input the maximum active scan time allowed for the implant.
- Add Sequences – Enter the sequence name and its scan time. Each entry will subtract from the remaining allowed scan time.
- Print Progress (Optional) – Print a copy of the current list of sequences and times at any point.
- Cooling Period – When the allowed active scan time is reached, start a cooling countdown. A pop-up will notify you when it is complete.
- Continue or Reset – After cooling, either keep adding sequences or reset the list to start over.
- Final Print – Once all sequences are completed, print a final copy for records.
Why are active scan times and cooling periods important?
Some MRI-conditional implants can only be actively scanned for a limited time to prevent heating or device malfunction. Cooling periods allow the implant and surrounding tissue to return to safe temperature levels before additional scanning can continue.
Active Scan Time Remaining
Sequences Run
Active Scan Time Completed
00:00
Cooling Period Countdown: 00:00
Cooling period complete! You may now reset sequences or add new sequences.
About this site
mricalculator.com is a free set of tools for MRI technologists, built by a working MRI tech. Everything here is made for the actual job — checking scan-time limits, finding implant labeling, and keeping SAR in check — not for textbooks.
More tools
- MR Implant Search Tool — build a targeted search for an implant’s MR conditions, with manufacturer quick links and phone numbers.
- SAR Reduction Checklist — a quick checklist for lowering SAR fast, made to glance at while you’re at the console.
Learn: plain-language MRI guides
- SAR Explained for MRI Technologists
- 9 Ways to Reduce SAR in MRI
- How Does an MRI Work? Explained Like You’re in 5th Grade
- Tattoos and MRI: What to Tell Patients
- Why You Can’t Find That Implant’s MRI Labeling
See all guides on the Learn page →
Why SAR matters
SAR — the rate the scanner deposits radiofrequency energy in the body — has had safety limits since the early days of MRI. But it only became the thing that decides how fast you can scan once two things changed. First, 3T scanners arrived, and SAR at 3T runs about four times higher than at 1.5T. Second, MR Conditional implant labeling started setting hard active-scan-time limits, like 30 minutes per session. So a scan that used to be a protocol question is now a safety question too: how much RF, for how long, and what does the implant allow. That’s what the calculator above is for — it keeps count so you don’t have to do the math by hand.
Built by a working MRI technologist. Educational content only — not medical advice. Always verify against the manufacturer’s official labeling; the radiologist and MR safety officer make the final call.