Nevermind, I figured it out. Now my only question is. Do I base my form on the query now? I didn't think entering data should be done on a form based on a query. Or am I wrong there. I need to the total calculated by my query as i enter the information in the form.

If you want to display the calculated total (like the difference between current and last fill mileages) on your form as you're entering data, basing your form on that query is actually a really good and common approach in Access. Forms can be based on tables or queries, and using a query is often better when you need calculations, extra fields, or need to pull in related data from other tables.

The only time you really run into trouble is if your query is too complex (for example, involving multiple tables joined in certain ways) or if Access makes the form non-updateable. As long as your query is updateable - which usually means it draws fields from a single table or from related tables in a way Access understands - you can add, edit, and delete records through the form just fine.

So, you're definitely not wrong to build a data entry form on top of a query, especially since you need to see that total calculated as you're entering each mileage record. If you find that your form suddenly won't let you type into fields, that probably means the query is non-updateable, and then you'd have to look at rewriting it or splitting calculations into unbound controls. But if it's letting you edit your data, you're good to go.

Thank you so much. Moving this database from using separate mileages all over the place to using one table for it is going to take time, but I've hit on the steps to slowly integrate the MileageT one step at a time. today I was able to completely convert the FuelStopT, FuelStopF, and all connected queries as well as the Assigned miles information. It's an active database, so it'll take a while before I have all the redundancies deleted and I'm solely relying on the MileageT