The tool, in your browser
The winter reserve calculator
Your overhead runs twelve months a year whether roofs sell or not. Add up one month’s nut, take off what a slow month still collects, and multiply by your slow months — that’s the tank. Put in what you’ve banked and the page shows the gap, then sizes the skim off each job that closes it before the phone goes quiet.
Free, and it asks for nothing. No email, no account, no sign-up. What you type stays in this browser on this device.
Read this first
This calculator only knows about this browser. Nothing you type is sent to us and nothing syncs, so the phone and the shop computer each keep their own copy — and anyone who opens this page on that computer can read your payroll, your draw and what you have in the bank. Clearing your browsing data wipes it, and a new phone won’t bring it along. For the copy that has to last, put the-winter-reserve-calculator.xlsx on the computer at the shop.
The calculator fills in right here in your browser. If this line stays put, JavaScript is off — the spreadsheet below does the same job.
How it gets used
- Work it top to bottom. Everything you type comes before anything the page works out, so you never carry a number before its inputs exist.
- Payroll is the line that moves the reserve most. Put in only the pay you actually carry when the phone’s quiet. If your crews are 1099 subs you’re not paying them with no work, so that line is smaller and your target is smaller. If they’re W2 and you keep them through winter, it’s bigger — and this reserve is what makes keeping them possible.
- A slow month is never really zero. Repairs, insurance work, a commercial job that doesn’t care about weather — that money lands whether or not you sold a re-roof, and it pays part of the nut. Be honest and be conservative: put in what a bad slow month collects, not a good one.
- Move the skim the day each deposit or final check clears. The rule is that it comes off every job automatically, not whatever’s left over at the end of the month.
- FULL means stop. Once the tank reads full, quit skimming and let it sit — that money is next winter’s payroll. Draw it down through the slow months on purpose, then refill next summer.
Before you act on it
Nothing here is a target handed to you
The numbers in the boxes are the file’s EXAMPLE column — a made-up shop with a $37,000 nut, $12,000 still collected in a slow month, five slow months and $60,000 already banked. They show as faint examples so the page does something the moment you open it, and they are not an industry figure or a goal. Nobody is telling you $125,000 is your number. Your number is your own overhead against your own dead stretch, and it is the only one this page cares about.
Where the money sits is a business decision, not a spreadsheet one. A separate account the debit card can’t reach is the point of it; what kind of account, and anything to do with tax, is a question for your own accountant.
Want it in a spreadsheet?
The same calculator as a spreadsheet
the-winter-reserve-calculator.xlsx is this calculator as a spreadsheet — the same four blocks, the same formulas — for the computer at the shop. Four differences in the page’s favour: leaving the slow-month count empty leaves the target blank here, where the file quietly prints a $0 target over a real nut; a box holding something that isn’t a number says so and is left out, where the file totals around it; a job count or a skim of zero says so, where the file shows a divide error; and the skim per job is rounded up to the cent, so it actually closes the gap. Two the other way: the file keeps its worked EXAMPLE column side by side with yours, which is a genuinely good way to check your own arithmetic, and it’s a real file that survives a cleared browser. The sheets ask for your email once; this page never does.
The play behind it — M6-11 Fill the Tank in Summer So Winter Doesn't Break You — is why the tank gets filled in summer and drawn down on purpose, and the sheet notes spell out every column and formula.