When a campaign runs on more than one platform, the easiest report is a column of totals. It is also where most reporting mistakes happen. Each platform measures with its own definitions, time zones and history limits, so a number that is correct inside one platform can become wrong once it is added to another. The rules below are the ones Mecrio applies in its own reports, and you can use them in any spreadsheet.
Rule 1: add the counts, then calculate the rates
Rates such as click-through rate are ratios. Averaging them gives every platform the same weight, whatever its volume. Suppose platform A had 10,000 impressions and 100 clicks, a 1% click-through rate, and platform B had 1,000 impressions and 50 clicks, a 5% rate. The average of the two rates is 3%. The real combined rate is 150 clicks divided by 11,000 impressions, about 1.4%. The same applies to daily trends: average the days and the quiet days count as much as the busy ones.
- Click-through rate: total clicks divided by total impressions, times 100.
- Cost per click: total spend divided by total clicks.
- Cost per thousand impressions: total spend divided by total impressions, times 1,000.
- Cost per conversion: total spend divided by total conversions.
- Return on ad spend: total revenue divided by total spend.
- Conversion rate: total conversions divided by total clicks, times 100.
Mecrio calculates every rate from one set of formulas, and a trend over several days is built from summed clicks and summed impressions, never from an average of daily rates.
Rule 2: an empty value is not zero
If there were no conversions, cost per conversion does not exist. Writing 0 would say the conversions were free. The same holds for click-through rate without impressions and for cost per click without clicks. In Mecrio a rate whose denominator is zero stays empty and is shown as a dash, so a missing value is never read as a measured result.
Rule 3: never add reach across platforms
Reach counts unique people or accounts inside one platform. Meta, for example, defines it as the number of Accounts Center accounts that saw your ads at least once, and notes that the metric is estimated. Someone who saw your ad on two platforms is counted once by each, and neither platform knows the other's audience. Adding the two numbers therefore counts that person twice. Even within one platform, reach over a month is not the sum of daily reach. Platforms also limit how far unique counts go: LinkedIn's reach metric is only available for date ranges of up to 92 days, and Google's unique users metric cannot be aggregated and is limited to 92 days.
That is why Mecrio does not show a combined reach for a campaign that runs on several platforms. Reach and frequency stay with the platform that measured them.
Rule 4: conversions mean different things on each platform
A conversion on one platform is rarely the same event as a conversion on another. A few definitions from the platforms' own documentation:
- Google counts only the conversion actions you set to be included in its Conversions column.
- TikTok counts the times your ad resulted in the optimization event you selected.
- LinkedIn counts the times people took a desired action after clicking on or seeing your ad, so views count too.
- Reddit's purchase figure that Mecrio reads counts conversions after a click only.
- Microsoft Advertising leaves revenue from conversion goals that are excluded from bidding out of its Revenue column.
Adding these together produces a number that does not describe any single thing. Mecrio adds conversions or revenue from two platforms only when both count the same event under the same attribution. With the definitions on record today, no two of the nine platforms meet that test, so conversions and revenue are shown per platform, side by side.
Rule 5: attribution, time zones and late data
Attribution decides which conversions are credited to an ad. Snapchat's default windows are 28 days after a swipe and 1 day after a view. LinkedIn includes conversions after someone only saw the ad, while Reddit's purchase count only includes conversions after a click. Two platforms can therefore report the same sale, or neither of them can.
Days are not cut at the same moment either. Meta reports in the ad account's time zone, Microsoft's downloaded report data is relative to UTC, and Reddit's metrics default to UTC. Yesterday on one platform can cover different hours from yesterday on another. When the platforms in a campaign close the day at different moments, or the moment cannot be confirmed, Mecrio does not build day-by-day period comparisons across them.
Recent numbers also move. Meta's insights refresh every 15 minutes and do not change after 28 days. Google refreshes clicks, impressions and cost hourly in most cases. X finalizes metrics after 24 hours, and spend generally within 3 days. Snapchat finalizes metrics 48 hours after the end of the day, and Reddit says metrics may take up to 6 hours to stabilize. Treat the last few days as provisional.
Rule 6: all time does not cover the same period everywhere
Reddit's reports go back 24 months. Pinterest's standard report cannot start more than 90 days back, although its slower report job goes back 2.5 years. X's standard analytics request covers up to 7 days at a time. Mecrio reads up to 24 months on Reddit, 90 days on Pinterest, 7 days on X and the last 3 years on Microsoft Advertising, where the 3 years are Mecrio's own choice. When a campaign started before that window, the total is labelled as at least that amount, and the start of the covered period is shown.
Rule 7: do not mix currencies
Ad accounts can use different currencies. Without an exchange rate there is no correct total spend, and an invented rate would make every cost metric wrong. Mecrio does not convert currencies. When the accounts in a campaign use different currencies, spend stays per platform and the combined money figures are left empty.
Checklist before you share a cross-platform report
- Use the same date range everywhere and note each platform's time zone.
- Sum counts first, then recalculate every rate from the sums.
- Keep reach and frequency per platform.
- Combine conversions only when the definitions and attribution match; otherwise show them side by side.
- Mark the most recent days as provisional.
- Check that all accounts use the same currency before adding spend.
- Say what period all time actually covers for each platform.