Pacing variance formula, with a worked example

Pacing variance is the percentage by which actual ad spend over a period differs from the spend the budget expected for that period.

Positive means spend is ahead of budget. Negative means it is behind. A client with a €3,000 monthly budget that spent €1,520 in the last 14 days is at +10.0%, because the budget expected €1,381.58 for those days.

The pacing variance formula

daily budget       = monthly budget / 30.4
expected spend     = daily budget × days in the period
pacing variance %  = (actual spend - expected spend) / expected spend × 100

30.4 is 365 days divided by 12 months, rounded. The 30.4-day month entry explains why.

Worked example in euros

A client on €3,000 a month spent €1,520 over the last 14 days.

expected spend   = 3,000 / 30.4 × 14                     = €1,381.58
pacing variance  = (1,520 - 1,381.58) / 1,381.58 × 100   = +10.0%

The client is €138.42 ahead for the fortnight. At that rate, a 30.4-day month ends about €300 over budget.

Why pacing variance beats a budget-percentage threshold

A rule such as "tell me at 75% of budget" watches the month-to-date total. A client spending exactly to plan crosses 75% on about day 23 anyway, because 0.75 × 30.4 is 22.8. That threshold marks the calendar, not the drift.

Variance over a short window counts only recent days, so it moves before the total does. Say a €3,000 client jumps from €98.68 to €148 a day on the 11th. The 7-day variance reads +14% after two such days and +50% after seven. On the 17th, month-to-date spend is €2,023, or 67% of budget. The 75% rule is still silent.

Why one day's variance can be large

Google Ads Help, answer 6385083 sets the daily ceiling:

Your daily spending limit (two times your average daily budget for most campaigns) on any particular day.

With the daily budget set at the monthly budget divided by 30.4, one day can read +100% inside Google's documented limit. A longer window smooths that noise.

Why 10% ahead on day 3 is not 10% ahead on day 25

Spend 10% ahead of plan on day 3 is about €30 on a €3,000 budget, with 27 days left to absorb it. That is noise. On day 25 the same 10% is about €247, with five days left. That is roughly the final number.

Adswave's pacing alerts do not adjust for month position. A 10% rule uses the same 10% on the 3rd as on the 25th. Check the date before you act.

How Adswave computes it

Adswave sums the monthly budgets you enter per linked ad account in the Client dialog (Admin, Clients). Expected spend is that sum divided by 30.4, times the days in the window. Actual spend is Google Ads plus Meta spend over those days.

• Budget Pacing view. Each client card shows variance for rolling windows of 2, 14, 30, 90, 180 and 365 days ending today, plus a custom range, with Google and Meta columns. Variance is green at 2% or less either way, amber up to 5% and red above 5%. Today counts as a full day of expected spend. Its actual spend is still partial, so every window leans towards underspend until the day ends. An evenly spending client shows about -1.9% (green) in a 31-day month and about +8.6% (red) in a 28-day February.
• Pacing alerts. A rule compares actual spend over the last 1, 7, 14 or 30 complete days, ending yesterday, with monthly budget / 30.4 × those days. Thresholds are 5, 10, 15, 20, 25, 30, 45 or 50%, up, down or either. Rules run hourly in production and fire at most once per target in 24 hours. Overspend alerts covers scopes and emails.
• The free calculator. The budget pacing calculator uses the days elapsed you enter. It reads "Over pace" above +5%, "Under pace" below -5% and "On track" in between. It also projects month-end spend, which the app does not.

Budget Pacing and pacing alerts are on every plan.

Google Ads Help quoted from answer 6385083, checked 3 September 2026.