How To
How to calculate a daily budget
Many ad platforms require a daily budget rather than a total flight budget. To avoid over-spending or under-delivering, you need to divide the total budget evenly across all flight days.
The formula
Daily Budget
Daily Budget = Total Budget ÷ Number of Days
Count both the start and end date as active days. A campaign running 1 March – 31 March has 31 days.
Example
| Variable | Value |
|---|---|
| Total budget | $24,000 |
| Flight | 1 April – 30 June (91 days) |
| Calculation | $24,000 ÷ 91 |
| Daily budget | $263.74 |
Every day gets an identical slice: $24,000 ÷ 91 = $263.74. Underspend a day and its slice rolls into the days that remain.
Monthly budget to daily budget
If you have a monthly budget, divide by the actual number of days in that month — not 30. Months vary between 28 and 31 days, which affects the daily figure.
| Month | Days | Daily (for $10,000 monthly) |
|---|---|---|
| February (non-leap) | 28 | $357.14 |
| April / June / September / November | 30 | $333.33 |
| January / March / May / July / August / October / December | 31 | $322.58 |
Same money, more days: February’s daily budget is 11% fatter than March’s. Dividing by a flat 30 misses that.
Mid-flight adjustments
If a campaign has under- or over-spent in earlier days, you may need to recalculate the daily budget for the remaining flight. Use the remaining budget and remaining days:
Revised Daily Budget
Revised Daily = Remaining Budget ÷ Remaining Days
| Variable | Value |
|---|---|
| Spent by end of day 31 | $6,000 (plan said $8,176) |
| Remaining budget | $24,000 − $6,000 = $18,000 |
| Remaining days | 91 − 31 = 60 |
| Calculation | $18,000 ÷ 60 |
| Revised daily budget | $300.00 |
daily
days 1–31
days 32–91
Days 1–31 ran below the dashed plan line, so the unspent $2,176 spreads across the 60 days left: the sage column steps up to $300.
Try the Budget Calculator
Enter total budget and flight dates to get the daily budget and total days automatically.