tl;dr
Every report in Klar has a date range selector that controls which data is included
Standard reports include only activity (orders, visits) that happened within the selected date range
Retention reports work differently: the date range defines when customers were acquired, but all their activity from that point until today is included
The Repeat Repurchase Rate has its own variant: date range = when the repeat order was made, not the acquisition date
You can compare any period against the previous period or the same period last year using the Compare with toggle
Standard behaviour
In most reports, the date range works exactly as you'd expect: only activity (purchases, visits, etc.) that took place within the selected period is included in the calculations.
Retention report behaviour
Retention reports work differently — and for good reason.
In all retention reports, the date range defines when a customer placed their first order (their acquisition date). But all of that customer's activity from their acquisition date through to today is included in the metrics — not just activity within the date range window.
Example: You select January 2024 as your date range. Klar looks at all customers who placed their first order in January 2024, and then calculates everything they've done since — including orders in March 2025 — to give you their full repurchase rate, LTV, and so on.
This is intentional. Retention is about customers, not individual transactions. If you cut off the data at the end of the date range, you'd be looking at an incomplete picture of how those customers actually behaved.
All retention reports live in the Retention section of Klar. If you're unsure how a report handles its date range, check the top of its help article — we flag it where it applies.
Practical tip: In retention reports, always select a date range that ends today (or as close as possible). Selecting a range that ends in the past will make recent cohorts look artificially weak, since those customers haven't had enough time to repurchase yet.
Repeat Repurchase Rate — a special case
The Repeat Repurchase Rate has a slight variation on the retention behaviour. Here, the date range defines when the repeat order was made — not when the customer was first acquired. So you're looking at all repeat purchases made within the selected window (including from customers acquired before that window) and calculating how many of those went on to purchase again.
When this metric is shown on a chart, the data point is attached to the date of the prior purchase — the order that triggered the repurchase window.
Example: 1,000 customers placed a repeat order in February 2021. By today, 374 of them have placed another order. Your Repeat Customer Repurchase Rate for February 2021 is 37.4%.
Date Range Comparison
You can compare any date range against a previous period or the same period last year. This works in the Daily Overview and all Flex Tables.
To set up a comparison:
Open the Date Range selector (top right)
Click Set Custom Range
Enable the Compare with toggle
Select your two date ranges
Click Apply
The comparison data will appear alongside your primary period.