Budget Pacing Calculator
Enter a budget, spend to date and the flight dates to see whether a campaign is on pace, what daily spend the remaining days need to carry, and where delivery lands if nothing changes. Built for the check a trafficker makes every morning across a list of live lines.
Enter a budget, spend to date and the flight dates to see pacing. The end date must fall on or after the start date.
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Formula
Ideal Spend = Budget × (Days Elapsed ÷ Days Total) · Pace % = (Spend to Date ÷ Ideal Spend) × 100 · Required Daily = (Budget − Spend) ÷ Days RemainingDays are counted inclusive of both the first and last day of flight, and the current day counts as elapsed. Date arithmetic runs in UTC, because doing it in local time introduces off-by-one-day errors across a daylight-saving boundary — enough to move the pace figure by several percent on a month-long flight.
The catch-up trap
Falling behind is not a linear problem. Every day spent underpacing removes a day from the remaining window while leaving the shortfall intact, so the daily rate required to recover climbs steadily and then sharply. A flight at 60% pace halfway through needs about 1.4 times the original daily rate to land on budget. The same flight left alone until 80% elapsed needs roughly 2.7 times. Past about 1.5 times, the extra spend usually cannot be found by raising caps alone — you end up bidding higher and taking worse CPMs to buy inventory the campaign was previously losing, which is why acting in week two costs far less than acting in week four.
Check pace against delivery, not just spend
Spend pacing and impression pacing come apart whenever the CPM moves. A line that is on budget pace but running well above its planned CPM is quietly under-delivering impressions, and will miss an impression guarantee while looking healthy on a spend report. If the campaign carries a volume commitment rather than only a budget, pace both numbers and treat the worse of the two as the real position. The gap between them is also an early warning that the buy is bidding up to maintain delivery.
Frequently asked questions
- Does today count as an elapsed day?
- Yes. This calculator counts both the first and last day of flight, and treats the current day as elapsed — so on day one of a ten-day flight, ideal delivery is 10% of budget rather than zero. That matches how most DSP pacing reports work, but check your platform, since a few measure against completed days only and will read roughly one day behind this figure.
- What counts as acceptably on pace?
- Within about 5% either side of plan is treated as on track here, which reflects normal daily delivery variance. Outside that band the flight is drifting enough to act on, though a single unusual day near the start of a short flight can breach it without anything being wrong.
- Why can't I just raise the daily cap to catch up?
- Because caps only help if the inventory and the bid are there to absorb the extra spend. Once the required daily rate exceeds roughly 1.5 times the original even rate, you are usually asking the buy to win auctions it was previously losing, which means bidding higher and accepting a worse CPM. Raising caps without raising bids typically produces a flat delivery line and a shortfall.
- Should I front-load or pace evenly?
- Even pacing protects CPM and gives the campaign room to recover from a bad day. Front-loading is worth it when inventory is genuinely scarce, when a fixed event date drives demand, or when you need performance data early enough to optimise. What loses money is unintentional front-loading — an uncapped line that spends 40% of budget in the first three days and then sits idle.