> For the complete documentation index, see [llms.txt](https://support.caasie.co/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://support.caasie.co/campaign-settings/budget-and-spend-pacing/how-budgets-work.md).

# How Budgets Work

### What is the minimum budget for a campaign?

Ultimately, there isn't one, but that doesn't mean you can run a campaign with pennies. When you select your boards, CAASie will calculate a rough hourly budget that will cover your selected boards as a starting guide.

You can set your budget to be higher or lower than this recommendation, which can influence how your campaign performs.

* **Higher:** Your ad has the potential to play more frequently
* **Lower:** Plays may be limited by your available budget.

### Why wasn’t my budget completed?

If your campaign didn’t spend the full budget, it means CAASie couldn’t find enough eligible opportunities to show your ad before the campaign ended. 

**Here’s why that can happen:**

* **Limited screen availability matching your targeting (time, place, audience):** If your campaign is set to run only at specific times or locations, there may not have been enough available screens that met all those conditions. **Example:** if you targeted a small geographic area or limited hours, fewer plays may have been available to bid on.
* **Bid cap too low — other advertisers outbid you:** If your bid cap (the maximum you’re willing to pay per play) is too low, other advertisers may consistently win those auctions, leaving your campaign with fewer successful plays. The floor price of the screens can also be too high for your cap.
* **Campaign paused, expired, or waiting for ad approval:** Your campaign can only spend when it’s actively running. If it was paused or if the ad creatives were pending approval for a period, that downtime would reduce how much budget could be spent.
* **Low play volume in your chosen areas/times:** Some screens or time slots simply don’t serve as many plays. For example, late nights, small towns, or locations with lower foot traffic. In addition, some boards may have limited availability due to other advertisers already occupying those slots or media owners setting strict delivery limits. If screen activity or available inventory was low in your selected targeting zones, your campaign would have fewer opportunities to bid and spend its budget.

### What happens if my campaign doesn't use its whole budget?

Think of your budget as a permission, more than a commitment. If your campaign ends before the full budget is used, any remaining credit stays in your account to be used in other campaigns. It's one of the many benefits of a cost-per-play model.

Alternatively, you can move your campaign's end date in the 'schedule' tab of your campaign manager to extend your campaign for a longer period of time.