How to Build a Fleet Downtime Calculator in Google Sheets

Week 4 · Downtime · Operations

Every fleet manager knows downtime is expensive, but it’s hard to get everyone on the same page when the cost isn’t written down. Drivers feel it, dispatch feels it, customers feel it — but the number never hits a simple report.

A basic downtime calculator in Google Sheets can help you put real dollars to the hours your trucks and trailers spend out of service.

Step 1: Decide what “downtime” means in your operation

First, define downtime in a way that makes sense for your fleet. Common options:

• Any scheduled work missed because a unit was in the shop.
• Hours that a truck or trailer couldn’t be safely dispatched.
• Roadside events where a load or job was delayed or canceled.

Pick a definition and stick to it so your numbers stay consistent.

Step 2: Set up your downtime log

Create a sheet called Fleet Downtime Log with columns:

• Date
• Unit #
• Reason (breakdown, PM, waiting on parts, etc.)
• Hours out of service
• Loads / jobs impacted
• Driver assigned
• Notes

Each time a unit is down, log the event. This doesn’t have to be perfect — even rough numbers are better than guessing.

Step 3: Put a dollar value to each hour

Next, add a second section in your sheet that estimates the value of an hour of uptime. That might include:

• Average revenue per truck per day.
• Driver hourly cost.
• Any rentals or subcontractor costs used to cover.

If a truck typically brings in $800 per day over 10 hours, that’s about $80 per hour in potential revenue. Add driver cost and other overhead and you may be looking at $100+ per hour in impact.

Step 4: Build a simple downtime cost formula

Add a Downtime cost column to your log and use a formula like:

=HoursOutOfService * EstimatedCostPerHour

If a unit is down for 6 hours and you value uptime at $100/hour, that’s a $600 impact — even before you look at the repair bill.

Step 5: Review patterns by unit and failure type

After a few weeks or months, sort your downtime log by:

• Unit # (to see repeat offenders).
• Reason (to see common causes like tires, brakes, or aftertreatment).
• Driver (to catch training or abuse issues).

This is where you start seeing the same problems pop up. Once you can see them, you can plan maintenance and training to get ahead of them.

How on-site PM fits into the picture

A lot of downtime is “hidden” in shop trips — drivers shuttling units back and forth, waiting on call-backs, and trying to fit work around someone else’s schedule. Moving more of your PM and light repair on-site reduces those non-value-added hours.

The downtime calculator helps you justify those changes with numbers instead of just gut feel.

Want a ready-made template?

We’ve put together a simple downtime log and calculator in Google Sheets that you can copy and adapt to your fleet. It pairs well with our PM tracker and repair log.