What to put first in a fuel economy spreadsheet?

It is entirely up to you. There is no single 'correct' way.

For tracking MPG, many of us urge new Prius drivers to ignore that first maybe-full, maybe-partial, nobody-really-knows first tank. Start tracking when you personally fill it up. But no one is auditing it, so do as you wish.

 

First thing I did was stop at a gasoline station on my way home.
Tried adding fuel to the tank but it was in fact full.
That was my starting point.

 

Welcome & congrats!

You have a Gen 4 Prius, not the plugin Prime. @jerrymildred has done a lot of spreadsheet work on Priuus, PiP & Prime. Perhaps he can share some tips.

 

Congratulations. There are lots of mileage tracking apps that make it super easy. But a spreadsheet offers the ability to do more stuff with your data.

A regular Prius would begin as a pretty simple spreadsheet since you would just need to enter the odometer reading and the gallons and cost of the gas. Then you could have cells that would figure miles per tank, cost per mile, cost per mile compared to other cars' EPA ratings, cost per month, you name it. You can also use the data to generate graphs and charts. Your imagination and curiosity are the major limits.

 

I'd start with completely known conditions: record the odometer reading the first time you top it off, and go from there...

 

If you know for sure the tank was full from the dealer when you bought the car and know exact ODO reading at that point. I record it as "Free" gas to calculate my real cost of operation $cost/mile. Here is an example spreadsheet. Note the formula I use for $Cost/Mile is always $Cost from previous fill up divided by Miles driven from current ODO reading. Miles driven since the previous fill-up was using the gas previously purchased, not the gas you just paid. (The red arrow in Column G) Technicality, if you use the current price of gas you just paid for this calculation, it would generate a wrong number. Note the first $Cost/Mile in G4 cell has no value, because the gas was free. Colored boxes in my spreadsheet are calculated values, and I showed the actual formula used for the calculation.

 

I like your color scheme of making formula cells colored. I think I'll adopt that since it's easier to know instantly which cells need data and which don't. Also, I've been using the current fill up to calculate cost per mile. I guess it could work either way, depending if you want the final tank someday to be the full rather than empty. Since I still haven't needed to buy gas after my initial top-off when I got the car and that was only half a tank, I might make that change, too. Thanks for the ideas.

 

Yeah, after you do 20 fill-ups, it will average out. Not a big deal. But with very few gas fill you will do on your PRIME, the initial cost may show some discrepancy. That said, my spreadsheet for the PRIME looks different from the one shown for regular hybrid or gasser. I had to include the cost of kWh I used. I also maintain detailed record of all the cost that goes into the car (the top box of the spread sheet). The cost including fuel (gas and electric), initial purchase price, tax, fees, insurance, accessory, repair, maintenance, car wash, fluid, toll, parking, etc, etc are logged in a separate spreadsheet and the sum is carried over to the total cost to own/operate box. Eventually when I do sell or trade in the car, I can find out the actual final cost.

 

Yeah, there's a bunch of stuff from my PiP sheet that won't translate since the Prime doesn't offer up HV vs EV miles and percentages the same way. This should be actually more simple than the PiP, but not as simple as a normal hatchback. Our vacation next month will give me some data to play with, but it won't be typical data, of course. If not for vacation trips, it looks like I would be getting at least 6,000 miles per tank.

 

When I did mine, I topped it off, recorded how many miles were on the clock and went from there. Using Google Sheets, I now have so much info to look at. Don't mind the maintenance tab at the bottom, dealer has been doing my maintenance so I haven't been recording any maintenance details.

 

Here's a bare bones, liters/100km spreadsheet. No cost entries, just for fuel consumption record. Could actually be more bare bones, if you don't care to calc the in-dash vs calculated, just strip out those columns. Ditto for mpg equivalent.

You enter the date, and the odometer reading, and liters pumped, at each fill up. With one exception: at the first entry, you also need to enter the kms since last fill up. After that, the kms since last fill up are always calc'd, by subtracting old odo reading from current. Cumulative is calc'd to the right.

For each entry you need to copy and paste the previous line down, then edit.

 

@davran , your Base 2019 has the spare? As far as I know it's the only Canadian level with spare now. How are you liking it?

 

I have a simple spreadsheet. With your first fill, just enter it manually - but over 3 or 10 years, it's insignificant. Best to fill the day you get the car - that gets the car's l/100 working right too - the dealer's fill mightn't be really full - just enough to make the gauge look close.

The PURPLE is an overall summary with FUEL below


AND to the right and below (below makes it easier with deleting and adding rows)



The 3 TOTALS are computed in the purple section at the top.

 

This steel rim will work, what I'm using with snow tires:

Corolla steel rim, part no: 42611-02471 (2003-2008 corolla or matrix, CE, LS, S)

(In fall of 2010 I bought four of the above with the snow tire install, from Westminster Toyota. The rims were $70 apiece.)

Or if you want a temp spare, which is a bit lighter, and obviously less bulky (though the same outside diameter) the 2010 temp spare rim p/n is: 42611-20841

Above info was taken from McGeorge Toyota parts:

1992-2010 Toyota Spare Wheel 42611-20841 | McGeorge Toyota Parts

And tire: T135/80D16 101M

Above info found in 2010 Owner's Manual.

A TireRack tire that would work, looks much like the OEM:

https://www.tirerack.com/tires/tires.jsp?tireMake=Yokohama&tireModel=Y870B&partnum=38MD6YOTEMP&vehicleSearch=false&fromCompare1=yes

I believe 4th gen Prius Owner's Manual lists some differences in the temp spare, actually uses a 17" rim. But as far as I know, the 2010 temp spare in 16" is also 100% compatible, and I believe the tire OD is actually closer, to 195/65R15.

 

I got a salvage donut spare off Ebay for about $120. Looks new except some small paint scuffs.