Open your ads manager and you’ll find dozens of columns: impressions, reach, frequency, clicks, link clicks, CPM, CPC, CTR, conversions, cost per result. It’s easy to get lost among them, or to judge a campaign by whichever number catches your eye first. But three linked metrics explain most of what happens before the click, and two more explain what happens after.
This guide explains each metric, the maths that connects them and — most importantly — how to use them to find exactly where your campaign’s problem lies.
The core metrics
CPM: cost per thousand impressions
CPM = spend ÷ impressions × 1,000
What you pay for your ad to be shown a thousand times. It measures the cost of reaching an audience and is affected by competition for that audience, season, audience size and ad quality as the platform judges it.
CTR: click-through rate
CTR = clicks ÷ impressions × 100
Of every hundred people who saw the ad, how many clicked? It measures how compelling and relevant the ad is: the image or video, the offer, the copy, and how well it matches what viewers care about.
CPC: cost per click
CPC = spend ÷ clicks
What you pay for each visit. It isn’t an independent number — it’s the result of the two metrics above.
After the click: conversion rate and cost per conversion
Conversion rate = conversions ÷ clicks × 100, and cost per conversion (CPA) = spend ÷ conversions. A conversion may be an order, a sign-up or a message, depending on your goal. These two measure what happens on the landing page and in the store, not in the ad itself.
The relationship that explains everything
CPC = CPM ÷ (10 × CTR)
This means cost per click falls in only two ways: cheaper impressions or a higher click-through rate. It also means a high CPM isn’t a problem in itself. Look at this comparison:
| Ad A | Ad B | |
|---|---|---|
| CPM | SAR 6 | SAR 12 |
| CTR | 0.5% | 2% |
| CPC | SAR 1.20 | SAR 0.60 |
Ad B’s impressions cost twice as much, but its clicks cost half as much, because people click it four times as often. Anyone judging by CPM alone would pause the better ad.
Our CPM, CPC and CTR calculator works out all of these at once from your raw numbers, and has a mode for estimating impressions and clicks from a CPM and an assumed CTR.
How to diagnose a campaign: read the chain in order
Think of the campaign as a chain: impression → click → conversion. Look for the weakest link:
1. CPM is high compared with your usual campaigns
- The audience is very narrow or heavily contested.
- It’s a peak season (Ramadan, White Friday) when costs rise for everyone.
- The ad gets weak or negative engagement, so the platform shows it at a higher cost.
What to do: broaden the audience or test different ones, improve the ad itself, and plan for higher costs in peak seasons in advance.
2. CTR is low
- The ad doesn’t grab attention in the first second.
- The offer is unclear or unappealing.
- The audience doesn’t fit the product in the first place.
- The ad has been shown too often to the same people (high frequency) and they’re tired of it.
What to do: test different images, videos and headlines, put the product and offer up front, and refresh creative when frequency climbs. For common design mistakes, read our guide to digital ad design mistakes.
3. CTR is good but conversion is weak
The ad is doing its job and people click, but they don’t buy. The problem is usually after the click:
- The landing page doesn’t match the ad’s promise (a different offer or product).
- The page is slow on mobile.
- The price or shipping cost is a surprise.
- Checkout is long or payment options are limited.
What to do: review the page through a customer’s eyes on a phone, and analyse the purchase stages with our conversion funnel calculator to see exactly where visitors stop.
4. Everything looks fine but the campaign doesn’t profit
Reasonable CPM, good CTR, acceptable conversion — yet cost per order is higher than the order’s profit. Here the problem is economic, not advertising: your margin or average order value can’t carry the acquisition cost. Work out break-even with our ROAS calculator and revisit pricing and bundles.
Watch the difference between “clicks” and “link clicks”. Some platforms count every click on the ad (the image, page name, “more”) as a click, which inflates CTR and makes CPC look lower. For accurate analysis, use link clicks and compare them with actual sessions in Google Analytics.
Supporting metrics you shouldn’t ignore
- Frequency: the average number of times a person saw the ad. Rising frequency with falling CTR signals ad fatigue.
- Reach: the number of unique people who saw the ad, versus impressions, which include repeats.
- Video view rate: the share who watched the first seconds or half the video — it reveals how strong the opening is.
- ROAS: revenue versus spend, the metric that ties the whole chain to money; read about it in our ROAS guide.
How to compare properly
- Compare within the same context: same platform, same campaign objective, roughly the same period. Comparing an awareness campaign’s CPM with a conversion campaign’s is misleading.
- Gather enough data: judging an ad after a few hundred impressions means nothing.
- Your best reference is your own past campaigns: published “averages” vary widely by country, niche and year, and your own campaigns are the most accurate yardstick.
- Follow the trend, not the moment: a one-day CPM spike means little; two weeks of rising CPM deserves investigation.
Using metrics for planning
Metrics aren’t just for reports. If you know your usual CPM and CTR, you can estimate what an upcoming budget will deliver before you spend it: SAR 2,000 at a CPM of SAR 8 gives about 250,000 impressions, and at a 1.2% CTR about 3,000 clicks. From there, your conversion rate gives expected orders. To calculate budget directly from a sales goal, use our ad budget calculator.
Key takeaways
- CPM measures the cost of reach, CTR the ad’s appeal, and CPC the result of both.
- A high CPM isn’t a problem if CTR is high enough to bring cost per click down.
- Read the chain in order — impression, click, conversion — and find the weakest link.
- A good CTR with weak conversion means the problem is the page, not the ad.
- Compare within the same platform, objective and period; your own past campaigns are the best benchmark.
Frequently asked questions
What’s a “good” CPM or CTR?
There’s no universal number. Metrics vary by platform, country, niche, season and campaign objective. Good is whatever improves on your past campaigns and ultimately leads to a cost per order below the order’s profit.
Should I pay per impression or per click?
On most social platforms today you choose a campaign objective and the platform optimises delivery. More important than the billing method is choosing the right objective (sales, traffic, awareness), because it decides who sees your ad.
Why did my CPC suddenly rise?
Either CPM rose (competition, season or a narrower audience), CTR fell (ad fatigue or an audience change), or both. Check each one separately to find the cause.
The three metrics don’t give you the answer on their own, but they tell you where to look. Calculate them from your campaign numbers now with our free CPM, CPC and CTR calculator — and if you want your campaigns reviewed and the drivers of high costs diagnosed, get in touch.
