Common Media Planning Questions
Real questions junior media buyers, planners, and account managers ask — answered with formulas, benchmarks, and calculator links.
Pricing & Cost Metrics
- How do I calculate CPM?
- CPM = (Budget ÷ Impressions) × 1,000. Divide your total spend by impressions delivered, then multiply by 1,000. For example, $5,000 spent on 400,000 impressions = $12.50 CPM.
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- How do I convert CPM to CPC (or vice versa)?
- You need the CTR to bridge them. CPC = CPM ÷ (CTR% × 10). For example, a $10 CPM with a 0.5% CTR = $10 ÷ (0.5 × 10) = $2.00 CPC. Going the other way: CPM = CPC × CTR% × 10.
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- What is a good CPM?
- It depends on the channel, format, targeting, and time of year. Display banners might be $2–$8, video pre-roll $15–$30, CTV $25–$50+, and social varies widely. Compare CPMs within the same placement type rather than across channels.
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- What's the difference between CPC, CPM, and CPA?
- They measure cost at different stages: CPM is cost per 1,000 impressions (awareness), CPC is cost per click (traffic), and CPA is cost per conversion (action). Use the metric that matches your campaign goal.
- How do I calculate CPA?
- CPA = Spend ÷ Conversions. If you spent $10,000 and got 200 sign-ups, your CPA is $50. To lower CPA, you can reduce spend (lower CPMs/CPCs), improve targeting, or optimize the landing page to increase the conversion rate.
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Campaign Performance
- What is a good CTR?
- Benchmarks vary by format: display banners average 0.05–0.10%, rich media 0.10–0.30%, social feed ads 0.50–1.50%, and search ads 2–5%. Don't compare CTRs across channels — compare within the same format and placement.
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- What's a good ROAS?
- It depends on your margins. A product with 60% gross margin breaks even at about 1.7× ROAS. A product with 20% margin needs 5× ROAS just to break even. The "good" number is the one that generates profit after all costs.
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- What's the difference between ROAS and ROI?
- ROAS = Revenue ÷ Spend (a revenue multiple). ROI = (Revenue − Cost) ÷ Cost × 100 (a profit percentage). A 4× ROAS means $4 in revenue per $1 spent, but if costs eat up $3, your ROI is only 100%. ROAS ignores costs beyond ad spend; ROI accounts for them.
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- How do I calculate percent change for a report?
- % Change = (Current − Previous) ÷ Previous × 100. If CPC went from $2.00 to $1.76, that's ($1.76 − $2.00) ÷ $2.00 × 100 = −12%. Always include the direction (increase/decrease) and the absolute values for context.
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Planning & Reach
- How do I calculate reach and frequency?
- Impressions = Reach × Frequency. If you know any two values, you can solve for the third. A campaign that reached 500,000 people with an average frequency of 4 delivered 2,000,000 impressions.
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- What frequency is too high?
- There's no universal cap, but most brand campaigns aim for 3–7 frequency over a flight. Above 10, you risk ad fatigue and diminishing returns. Performance campaigns may tolerate higher frequencies if the ROI holds up. Monitor frequency weekly and rotate creative to keep it fresh.
- What are GRPs and TRPs?
- GRP (Gross Rating Points) = Reach % × Frequency against the total population. TRP (Target Rating Points) is the same formula against the target audience only. They measure media weight for TV, radio, and OOH. A 500-TRP plan is a common benchmark for a national TV flight.
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- How does budget pacing work?
- Even pacing divides total budget by flight days. Compare actual spend-to-date against the ideal even-pace line. If you've spent 60% of budget but only 40% through the flight, you're 20 points ahead of pace — slow down or you'll exhaust the budget early.
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Billing & Fees
- What's the difference between gross and net?
- Net is the actual media cost. Gross includes the agency commission on top. The commission is a percentage of gross, not net. At a 15% commission: Gross = Net ÷ 0.85. A $85,000 net buy = $100,000 gross.
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- What's the difference between markup and margin?
- Markup is relative to cost: (Sell − Cost) ÷ Cost. Margin is relative to revenue: (Sell − Cost) ÷ Sell. A 25% markup on $100 cost = $125 sell price, but the margin is only 20% ($25 ÷ $125). They describe the same profit differently.
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- How do tech fees affect my working media?
- Each fee layer (DSP, data, verification, ad serving) reduces the dollars that actually buy media. A $100,000 budget with 30% total tech fees means only $70,000 reaches the publisher. Always map out your fee stack and calculate the net working media.
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- What are typical programmatic tech fee percentages?
- DSP fees: 10–20% of media. Data/audience fees: 5–15%. Verification (viewability, brand safety): 2–5%. Ad serving: $0.05–$0.15 CPM (fixed). Total fee overhead is commonly 25–40% of the gross budget. Ask your vendors for a transparent fee breakdown.
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Still learning?
Check out the Media Math 101 guide for deeper explanations, or grab the interview prep cheat sheet to test yourself.