Two logs, side by side
The calculator gives you two identical journals: one for a Mercury retrograde window, one for an ordinary stretch of time exactly the same length. Pick a window from the pills above using verified astronomical station dates, not an astrology app’s guess, and the baseline builds itself automatically from the days immediately before or after it, whichever you choose.
Every entry becomes a card: pick a category, type the dollar amount, and optionally note that it caused a second expense, like a rush-shipping fee or a missed-work hour. A $210 phone repair with a $40 loaner-phone rental attached counts as $250, not $210, because the second number is the one that actually left your account.
Watch the totals and the delta live
As you add entries, both column totals update instantly, and the boarding-pass panel below shows the retrograde total on one half and the baseline total on the other, with the dollar difference stamped between them. If the retrograde side genuinely cost more, you get a plain red delta stamp. If it did not, the pass gets a calm green “no measurable spike” stamp instead, because a tie or a cheaper retrograde is exactly as real a result as an expensive one.
Where the money actually falls
The confidence bar right below the pass shows what share of your retrograde total is exact numbers from a receipt versus a rough guess from memory, so the comparison never pretends to be more precise than it is. The weekday heatmap further down plots every entry from both columns by day of the week it happened on, not by month, which is what lets you notice if your mishaps actually cluster on, say, every Tuesday, regardless of what the sky is doing.
If one single day carries most of the retrograde total, the day picker below the heatmap will show you exactly what share, so a $600 window that is really one $550 laptop repair on a single Thursday does not get quietly read as three weeks of chaos.
Before it even starts
If you are reading this before a retrograde window has begun, switch on the estimate helper. Enter how often each category of mishap usually happens to you per month and what it usually costs, and the calculator projects an expected total for a window of that length, using nothing but your own historical average. That projected number assumes no special effect either way, so it works as the same yardstick for the retrograde window and for any ordinary stretch of the same length.