PPC Daily Ad Budget Calculator

Enter the monthly budget ($3,000) and the campaign days it must cover (30). For a short promotion, use its real length: the same $3,000 over a 14-day sale is $214.29 a day. For an always-on Google Ads campaign, see the pacing section below for why 30.4 is the more accurate divisor.

Enter average CPC ($1.75) and conversion rate (3.5%) from the last 30 to 90 days of the same campaign or a close equivalent in your own account. A new account has no such history, so start with a cautious guess and replace it after the first weeks of data.

The results show a $100.00 daily budget, 57.1 daily clicks, 1,714 monthly clicks, 2.00 daily conversions and a $50.00 cost per conversion. That last number is simply CPC ÷ conversion rate: $1.75 ÷ 0.035 = $50. Budget size does not appear in it at all.

Daily Budget = Monthly Budget ÷ Campaign Days

Estimated Daily Clicks = Daily Budget ÷ Average CPC; Estimated Monthly Clicks = Daily Clicks × Campaign Days

Estimated Daily Conversions = Daily Clicks × Conversion Rate; Estimated Monthly Conversions = Daily Conversions × Campaign Days

Cost per Conversion = Daily Budget ÷ Daily Conversions, which reduces to Average CPC ÷ Conversion Rate

Working backwards from a goal: Monthly Budget = Target Conversions × Target CPA = (Target Conversions ÷ Conversion Rate) × Average CPC. Enter that result as the monthly budget. If CPC or conversion rate is zero, the click, conversion and cost outputs return 0.

A lead-generation account wants 200 conversions a month and can afford $40 each. Its history shows a $1.20 CPC and a 3% conversion rate, so $1.20 ÷ 0.03 = $40. The target is consistent with past performance. The goal needs 200 ÷ 0.03 = 6,667 clicks, and 200 × $40 = $8,000 a month.

Enter $8,000 over 30 days, $1.20 and 3%. The calculator returns a $266.67 daily budget, 222.2 daily clicks, 6,667 monthly clicks, 6.67 daily conversions, 200 a month and a $40.00 cost per conversion.

Scale changes what the numbers can support. This account collects 50 conversions in about 7.5 days, while the $3,000 account needs about 25 days. A $600 budget at a $2.50 CPC and 5% conversion rate also lands at a $50 cost per conversion, but at 0.4 conversions a day it takes about 125 days to reach 50. Same efficiency, very different amounts of data for automated bidding.

Google Ads Help ("About overdelivery and your average daily budget") says a campaign may spend up to twice its average daily budget on a given day to take advantage of traffic swings, and that across a month you will be charged no more than 30.4 times the average daily budget. Any served cost above your limits is credited rather than charged.

Two practical consequences follow. First, divide a calendar-month budget by 30.4, not 30: $3,000 becomes $98.68 a day and $8,000 becomes $263.16 a day. Dividing by 30 lets the monthly charging limit reach $3,040 on the first example. Enter 30.4 as campaign days to get these figures. The monthly click and conversion totals stay the same.

Second, a single day's spend can reach about $197 on a $98.68 daily budget, or about $533 on the $266.67 one, so judge pacing across the month rather than day by day. Other ad platforms pace budgets under their own rules, so check each platform's help pages rather than assuming Google's 2× and 30.4× apply.

Google's help article on the learning period says it can take up to around 50 conversion events or 3 conversion cycles for a bid strategy to calibrate after a change. The worked examples above show how directly budget controls that: 25 days, 7.5 days and 125 days to reach 50 conversions.

Google's Demand Gen campaign performance guide adds that the budget should be at least 10 times the target CPA. Read against a daily budget, that is $400 a day for the $40 target and $500 for the $50 one. The $266.67 and $100 budgets fall short. That guidance is written for Demand Gen campaigns, so treat it as a sign that small budgets starve automated bidding of data rather than as a rule for every campaign type.

If the budget cannot reach those levels, consolidate campaigns so conversions pool in one bid strategy, optimise toward a more frequent conversion action, or avoid changing targets while the strategy is still learning.

The projection is linear. Real CPCs usually rise as a budget pushes into more competitive or lower-intent auctions, and conversion rates can move either way. Conversions also lag clicks, so the first days of a new budget will show fewer conversions than the arithmetic suggests.

The projection is also only as meaningful as the conversion you count. If the account's conversion rate includes lightweight actions such as page views or button clicks, the cost per conversion will look far cheaper than the cost of a lead or sale, and a budget sized from it will under-deliver the outcome you actually want. Size the budget from the conversion action you would pay for.

The calculator does not model day-of-week or hour-of-day patterns, overdelivery, impression share lost to budget or rank, or conversion value. Treat its output as a starting cap to test and revise once real performance data arrives.

Check where your CPC comes from with the CPC calculator, or plan an impression-priced buy with the CPM calculator. A $40 or $50 cost per conversion only means something against what a customer is worth: the marketing CPA calculator puts acquisition cost in context, and the break-even ROAS calculator shows the return your margin requires before spend turns a profit.

Once the campaign has run, the UTM attribution ROI calculator tests how much of the reported return depends on the attribution model.