Short answer
The MCS-150 is the form that keeps your USDOT registration current. Under 49 CFR 390.19, you must update it every 24 months: the last digit of your USDOT number sets the month (1 is January through 9 for September, 0 for October), and the next-to-last digit sets the year (odd digit, odd years; even digit, even years). Failing to update leads to deactivation of the USDOT number and possible civil penalties.
- You must also update whenever your information changes, and the truck and driver counts you report feed into UCR fees and how underwriters see your fleet.
Working out your due date
Take your USDOT number and look at the last two digits.
- Last digit = month. 1 January, 2 February, and so on through 9 September; 0 is October.
- Next-to-last digit = year. Odd means file in odd-numbered years; even means even-numbered years.
FMCSA's example: USDOT 123456 ends in 6 (June) and the next-to-last digit is 5 (odd), so the update is due by June of odd years. You can file early; FMCSA says an update made in the 12 months before the due date satisfies the requirement. You can check your current record with our DOT lookup.
| Last digit | Month | Last digit | Month |
|---|---|---|---|
| 1 | January | 6 | June |
| 2 | February | 7 | July |
| 3 | March | 8 | August |
| 4 | April | 9 | September |
| 5 | May | 0 | October |
What happens if you miss it
Section 390.19 says a carrier that fails to complete the biennial update is subject to civil penalties under 49 U.S.C. 521(b)(2)(B) and deactivation of its USDOT number, and a carrier with a deactivated number is prohibited from conducting transportation. FMCSA says that if your number is inactive, you need a paper form to update it rather than the online portal.
A deactivated USDOT number causes problems far beyond FMCSA: broker onboarding platforms check status, and TxDMV requires a valid USDOT number for Texas intrastate authority.
Why insurance cares about the MCS-150
The MCS-150 shows power units, drivers, and mileage. Underwriters compare those numbers to your application. A record showing 3 trucks when you are insuring 10, or the reverse, raises questions and can slow a quote. Your MCS-150 count also feeds the UCR fee. Keep it accurate when you add or drop trucks, and review it before renewal.
Common questions
Do I need to file if nothing changed?
Yes. The biennial update is required on schedule even if your information is the same.
Does the biennial update apply to intrastate carriers?
It applies to anyone with a USDOT number, including Texas intrastate carriers that registered with USDOT.
Is the MCS-150 an insurance filing?
No. Insurance filings (BMC-91X, Form E) are made by your insurer. The MCS-150 is your own registration update.
Sources
- 49 CFR 390.19, Motor carrier identification report (Cornell LII). Biennial update schedule by USDOT digits; penalties and deactivation.
- FMCSA, When am I required to file a biennial update?. Month and year schedule, early filing within 12 months, paper form for inactive numbers.
This page explains insurance, not law. Have your attorney review indemnity and contract language; our job is making the insurance match it.