Wevion converts spend at per-day historical rates via an EUR intermediate. Display currency defaults to each account's native; switch to one to compare.

Exchange rates per day — multi-currency analytics

Wevion can show all your accounts in a single display currency, converting each account's native-currency values through an EUR intermediate at per-day historical rates — each transaction is converted at the rate that applied on the day it occurred, not today's rate. The display-currency preference defaults to each account's native currency; switch it to one currency (e.g. EUR or USD) to put multi-currency accounts on a comparable scale.

Who is this for

Mediabuyers and agencies running ads in multiple currencies (e.g. EUR for IT clients, USD for US clients, GBP for UK). Anyone wondering why Wevion's total differs from naïve "apply today's FX rate" math.

How currency conversion works

For each value (spend, purchase value, etc.) in a non-native account:

1. Start from the native ad-account currency (Meta US = USD, Meta IT = EUR, etc.)
2. Convert to EUR using the rate that applied on the transaction date
3. Convert from EUR to the chosen display currency using the rate on the same date
4. Aggregate in the display currency

EUR-as-intermediate is a common pattern: it avoids storing every currency pair — only EUR↔X rates are needed.

Per-day rates (not "today's rate")

Each transaction is converted at the historical rate for its date. Example — viewing "Last 30 days" in USD with a Meta IT (EUR) account:

• Day 1 spend €100 → converted at the day-1 USD/EUR rate
• Day 15 spend €100 → converted at the day-15 rate
• Day 30 spend €100 → converted at the day-30 rate
• Total = sum of per-day USD values, not €3,000 × today's rate

FX rates fluctuate, so a flat "today's rate" conversion would misrepresent historical spend and earnings.

The display-currency preference

Wevion's display currency is a preference you set, not a per-query field you type:

• Default = Account (native): each account shows in its own currency; multi-currency portfolios then appear on different scales
• A specific currency (EUR, USD, GBP, …): every account is converted to that one currency at per-day rates, so figures are directly comparable and can be summed

Switch it when you need one comparable scale across accounts; leave it on Account (native) when you want each account to match its own platform UI exactly.

Source of FX rates

Wevion ingests FX rates daily (typically central-bank/commercial feeds), updated once per day's close, covering major and most regional currencies. Rates are stored in the exchange_rate table for audit.

Implications for analytics

Per-account table

When the display currency is set to one currency, the Performance per account table (an-108) converts every account to it, so you can compare and total spend and ROAS across accounts with different native currencies.

Period comparison

Comparing last 30 days vs the prior 30 days: each side uses its own per-day rates, so small variance is possible if FX moved between the periods. See an-113 comparing periods.

Export

CSV / Excel export (an-116) reflects the same display currency as on screen, with one row per day.

Edge cases

• Switching the display currency: historical data is re-rendered at historical rates — no data loss, just relabelled.
• Postback in a different currency than spend: e.g. spend in EUR, purchase value in USD — each is converted to the display currency at its own per-day rate, so ROAS aggregates correctly.
• High-volatility currencies: large day-to-day variance in totals is expected behaviour of per-day rates.

When multi-currency matters

• Single-currency workspace (e.g. one EU agency, all EUR accounts): the display currency doesn't materially change anything — keep the default.
• Same brand across geos in different currencies: set a single display currency for consistent, comparable reporting.

Common mistakes

• Expecting today's-rate math to match: per-day rates differ from a naïve flat conversion.
• Switching the display currency mid-comparison: it muddles period deltas — pick one and stick with it.
• Comparing a converted Wevion total to a platform's native total: to match a platform exactly, set the display currency to Account (native).

Common issues

• Total off by a few %: FX variance between the platform's reporting rate and Wevion's stored rate; small variance is expected.
• Very old data shows a missing rate: rare FX-feed gap; contact an admin.

FAQ

How does Wevion convert currencies across accounts?

Wevion converts each account's native-currency values to EUR as an intermediate, then from EUR to your chosen display currency, aggregating the result. EUR-as-intermediate avoids storing every currency pair — only EUR-to-X rates are needed. The display currency defaults to each account's native currency, and you can switch it to a single currency to put all accounts on one comparable, summable scale.

Does Wevion use today's exchange rate or historical rates?

Wevion uses per-day historical rates: each transaction is converted at the rate that applied on the day it occurred, not today's rate. Viewing 30 days in USD therefore sums per-day USD values rather than multiplying the EUR total by today's rate. Because FX fluctuates, a flat conversion would misrepresent what was actually spent and earned over the period.

How do I compare accounts that use different currencies?

Set the display-currency preference to a single currency (for example EUR or USD) instead of Account (native). Wevion then converts every selected account to that currency at per-day rates, so the Performance per account table and KPI grid show figures you can compare and total directly. Leave it on Account (native) when you want each account to match its own platform dashboard.

Why does my Wevion total differ slightly from the platform UI?

When the display currency isn't the account's native currency, Wevion converts via per-day rates, so a small variance of roughly 1-2% for major pairs is expected versus the platform's native totals. To match a platform exactly, set the display currency to Account (native) for that account. Otherwise, treat modest FX variance as normal rather than an error.

Related articles

• Data freshness — how often analytics update
• Performance per account table
• Analytics overview — Advertising and Store & Business