When comparing advertising amounts from different marketplaces, retain the original currency for every figure and document any conversion used for the comparison. Do not add unlike monetary amounts or treat a currency conversion as proof that the campaigns had equivalent conditions. Review campaign scope and outcomes separately from the arithmetic.
Identify the currency of every amount
Start with the source reports and record the currency alongside spend, attributed sales, or other monetary figures you intend to compare. A spreadsheet column labeled amount is insufficient when several marketplaces are involved. Preserve the original values so the comparison can be traced back to the reports.
Do not infer currency solely from the book's language or the author's location. Use the actual report context. If the currency is unclear, resolve that ambiguity before combining the data rather than applying a convenient assumption that makes the totals appear complete.
Separate monetary values from other measures
Counts and monetary amounts answer different questions. Keep clicks, orders, and currency-denominated values labeled distinctly, using the definitions of the relevant report. This reduces the chance that a combined table gives a false impression of consistency merely because all its cells contain numbers.
Record the campaign, marketplace, and reporting period with each result. Two amounts expressed in the same currency can still describe different scopes. Currency labeling is necessary for a valid comparison, but it does not replace checking what the figures represent.
Document the conversion method when one is needed
If a common currency is useful for an internal comparison, state the exchange-rate source, date, and method applied. Keep the converted figure separate from the original amount. Label both columns explicitly so a later export does not lose the distinction. A reviewer should be able to reproduce the calculation and understand whether it uses one comparison rate or another clearly described approach.
Do not silently mix rates from different dates or treat a converted reporting figure as identical to an actual settlement amount. Those may serve different purposes. Identify what the comparison is meant to show and avoid giving a converted estimate more precision or authority than its assumptions support.
Keep conversion effects separate from campaign changes
A converted total can change because the underlying campaign result changed, because the conversion assumption changed, or both. Record those effects distinctly when comparing periods. Otherwise, a movement in the displayed total may be described as better advertising performance without sufficient evidence.
Inspect the original-currency figures alongside the common-currency view. This helps reveal when an apparent difference depends mainly on the comparison method. Do not use the exercise to promise what future exchange rates or campaign outcomes will be; preserve the limited purpose of the historical observation.
Review the marketplaces as different contexts
Converting amounts does not make two campaigns equivalent. The book's available formats, listing presentation, audience, and observation period may differ. Record material differences before drawing conclusions about which campaign performed better or what a larger test might produce.
Use current KDP advertising guidance to understand the relationship between advertising reports and broader book reporting. A common-currency table can support organization, but it does not establish that every sale belongs to a particular campaign or that reporting categories align automatically across the material you collected.
Write a conclusion proportionate to the evidence
Summarize the original observations and the assumptions used to compare them. State unresolved differences rather than hiding them behind a single combined total. If the evidence supports only a limited observation about a particular period, keep the conclusion at that level.
Preserve the source reports, conversion record, and comparison worksheet together. This makes later review possible when a question arises about an amount or a changed assumption. The useful result is a transparent comparison that helps the author understand the data, not a precise-looking number used to justify spending without examining what the reports actually establish.
Frequently asked questions
Clear answers for this publishing decision.
Can I add campaign spend from different currencies directly?
No meaningful combined monetary total results from adding unlike currencies without a defined conversion. Preserve the original amounts and document any common-currency calculation used for the comparison.
Does conversion make two marketplace campaigns comparable?
It addresses one arithmetic issue. You still need to review the book, campaign scope, reporting period, and other material differences before interpreting the results as equivalent tests.
What should be saved with a converted comparison?
Keep the original reports and currency labels, the exchange-rate source and date, the applied method, and the purpose of the calculation. Distinguish the comparison from actual settlement records where relevant.
What does this book cost to print and produce, and what should the list price be?
Printing cost follows from the trim, ink, and page count, the list price sets the royalty after that cost, and the production budget should be estimated before generation starts, so compare these numbers before you commit to a format or a plan.
See what a book project costs in credits