Budget Pacing Calculator
A straight-line projection from spend-to-date and days elapsed: it assumes the rest of the month spends at the pace the month has run so far. Useful as a mid-flight check on whether a campaign is tracking under, on, or over budget — without opening a query editor. It does not model weekend dips, seasonality, or a bid change made yesterday.
Projected Spend = (Spend to Date ÷ Days Elapsed) × Days in Month
₹3,75,000
Straight-line projection: assumes the rest of the month spends at the same daily rate.
Under pace
What each field wants
- Spend to date
- Actual spend so far this month, from the ad platform's billing view rather than the campaign reporting view — the two disagree during the period because reporting lags finalised charges by a few hours.
- Days elapsed
- Completed days, not including today. Today is partial, and including it drags the daily average down and makes you look under-paced every single morning.
- Days in month
- The billing period length — 28, 30 or 31. If you pace on a 4-week cycle rather than a calendar month, enter 28 and keep it consistent.
- Monthly budget (optional)
- The committed budget for the period, so the tool can report the projected variance rather than just the projected total.
How this number is derived
Straight-line projection, stated plainly
Daily rate is spend-to-date divided by completed days; the projection is that rate multiplied by the days in the period. It is the simplest possible forecast and it is right more often than elaborate ones, because most of what happens to pacing mid-month is a change you made, not a pattern a model could have extrapolated.
The pacing index is the number to watch
Pacing index = projected spend ÷ budget. Above 1.0 you will overspend; below 1.0 you will underspend and leave the budget unused. Most teams treat 0.95–1.05 as on-pace and act outside that band. Reading the index is faster than reading the currency figure because it is comparable across campaigns of different sizes.
Early-month projections are unreliable, and predictably so
On day 2, one anomalous day moves the projection by half. On day 10, it moves it by a tenth. Do not act on a pacing projection before roughly the fifth day of a period unless the variance is extreme — the noise genuinely exceeds the signal, and the usual result of acting early is a bid change that then has to be reversed.
Under-pacing is a delivery problem, not a budget problem
If a campaign cannot spend its budget, raising the budget changes nothing. Under-delivery means the auction is not giving you impressions at your bid: the causes are bid too low, audience too narrow, ad schedule restricted, or creative fatigued to the point of losing the auction. Diagnose delivery, then adjust budget.
Day 12 of a 30-day month
- Monthly budget
- ₹6,00,000
- Spend through day 12
- ₹2,76,000
- Days in month
- 30
Daily rate = ₹2,76,000 ÷ 12 = ₹23,000/day
Projected spend = ₹23,000 × 30 = ₹6,90,000
Variance = ₹6,90,000 − ₹6,00,000 = ₹90,000 over
Pacing index = 6,90,000 ÷ 6,00,000 = 1.15
Required rate for the remaining 18 days = (₹6,00,000 − ₹2,76,000) ÷ 18 = ₹18,000/dayPacing 15% hot. Holding to budget means dropping the daily rate from ₹23,000 to ₹18,000 — a 22% cut for the rest of the month, which is a larger intervention than the 15% overage suggests. The later you notice, the sharper the correction has to be; that asymmetry is the whole argument for checking pacing weekly rather than on the 25th.
Reading the pacing index
Projected spend ÷ budget. Bands assume you check at least weekly.
| Below 0.90 | Under-delivering | Investigate delivery — bid, audience size, schedule, creative fatigue. Raising budget will not help. |
|---|---|---|
| 0.90 – 0.95 | Slightly under | Usually fine. Consider a modest bid or budget increase if performance is good. |
| 0.95 – 1.05 | On pace | No action. Resist the urge to fine-tune inside this band. |
| 1.05 – 1.15 | Running hot | Correctable with a small daily-cap reduction if caught before mid-month. |
| Above 1.15 | Intervene now | The required correction grows non-linearly with how late you catch it. |
What this assumes, and what it doesn't model
Assumptions
- The remaining days spend at the same average rate as the elapsed days.
- Spend-to-date is final, not still settling. Platform figures for the last 24–48 hours frequently revise upward.
- The budget is a hard ceiling for the period rather than a soft target.
Deliberately not modelled
- No day-of-week weighting. B2B accounts spending far less at weekends will read as over-paced on a Friday and under-paced on a Monday.
- No seasonality. A projection made on 20 November does not know about Black Friday, and will understate the month badly.
- Does not model auction cost inflation — if CPMs rise during a peak period, the same delivery costs more than the projection assumes.
- Ignores changes you have already made. If you cut bids yesterday, the elapsed-days average still contains the old, higher rate.
- Single-campaign view. It does not model budget shared across a campaign group or a portfolio bid strategy reallocating spend between campaigns.
Common questions
Should I include today in days elapsed?
No. Today is a partial day, so including it divides a partial spend by a whole day and understates your run rate. Every morning, the campaign would appear to be under-paced. Count completed days only.
The projection swings wildly day to day. Is it broken?
Early in the period, no — that is the arithmetic. With few elapsed days, each new day is a large fraction of the average, so the projection is genuinely unstable. It settles as the denominator grows. If it is still swinging after day 15, you have real volatility in delivery, which is worth investigating on its own.
How does this work with platform daily budgets?
Both Google and Meta may spend above your daily budget on a given day (Google allows up to 2x) and compensate on other days, capping you at roughly your daily budget multiplied by the days in the month. So daily overspend is expected and not a reason to act; the monthly projection is the level at which the cap actually binds.
What about a campaign that started mid-month?
Enter days since the campaign started as "days elapsed", and days remaining in the period plus those elapsed days as "days in month". The projection then answers "at this rate, what will this campaign have spent by period end?" rather than assuming it ran from day one.
Last reviewed August 28, 2026.