Hi Airtable team 👋 

I'm building a master fulfilment dashboard using Interface Designer, based on a table (Partner KPI's) where each record represents daily performance data per partner.

One of the most important metrics I want to track is:

Cost per Scheduled Consultation = Ad Spend / Number of Consultations Scheduled

Right now, this is calculated per day via a formula field on each record.

❌ Problem 1: The dashboard shows an average of the per-record ratios
When I display this KPI on an interface, Airtable averages the daily cost-per-consultation values instead of calculating:

Total Ad Spend for selected period / Total Scheduled Consultations for selected period

This leads to completely misleading values, especially if some days have very few or zero consultations, which massively skews the average.

❌ Problem 2: No support for weighted averages or cross-record ratio KPIs
I need to be able to calculate:

SUM(Ad Spend) / SUM(Consultations Scheduled)
...for a given partner and time period filter (e.g. EZ Build for the last 5 days).

But this kind of aggregate ratio or weighted average does not seem possible in Interface Designer right now.

✅ Desired behavior
When a user selects a partner and a date range in the dashboard, I want to display:

Cost per Scheduled Consultation =
Total Ad Spend (in filtered records) ÷ Total Consultations Scheduled (in filtered records)

Not the average of Ad Spend / Consultations Scheduled field values on each record.

🛠️ Possible workaround (but not ideal)
I'm aware that I could potentially:

Build a summary table via linked records and rollups

Calculate totals and derive the ratio there

Then reference that in the dashboard

But this quickly becomes unscalable and rigid when working with many filters (e.g. dynamic date ranges, partner filters, etc.).

🙏 Feature request
Please consider adding support for:

Aggregate calculations across filtered records in Interfaces

Weighted average support

Custom expressions like SUM(X)/SUM(Y) for KPIs

Let me know if I can provide an example base or video walkthrough.

Thanks in advance!

Best,
Andreas!