Daily budget

A daily budget is rarely a hard cap on each day. Platforms treat it as an average and let spend rise on days with more opportunity. The rules differ by channel, and they decide how far one day can run over.

ChatGPT ads average the daily budget over 7 days: spend can reach 2× on one day but no more than 7× across the Sunday-to-Saturday week. Google sets a daily spending limit of 2× the average daily budget and a monthly limit of 30.4× for most campaigns. Gravity lets spend on one UTC day reach 110% of the daily budget, then stops serving until the next day.

Minimums differ too. ChatGPT self-serve requires USD 25 per day, varying by currency (for example EUR 15 or GBP 15), and its API returns an error stating the required amount when a request is below it. Gravity has no minimum and lets you start with any daily budget.

Read a daily budget as a weekly or monthly figure divided by days, and keep enough headroom for the overspend days each channel allows. Admux budgets work at campaign level: you set a total budget and an end date, Admux reserves the full amount when you submit, and the channel controls daily pacing. If approval arrives late, the remaining budget may be spent over fewer days, while the total and end date stay the same. Because the full budget is reserved up front, daily overspend on a channel can’t take spend past what you authorized. GET /channels lists each channel’s minimums through Admux, and key spending limits cap new authorizations, not daily delivery.