Free calculator
Margin of safety calculator
How much of the month could disappear before it stops paying for itself, expressed in the three units an operator actually feels: orders, euros and days of trading.
A margin of safety calculator measures the distance between what your store sells and what it needs to break even. It reports the cushion three ways: the orders you could lose, the net revenue that represents, and the days of trading it would take to use it up.
Your month
What each order and each month costs
Share of the month you could lose
30,2%
213 orders and €18.105,00 of net revenue above break-even: about 9,4 days of trading could disappear before the month stopped paying for itself.
33Break-even orders
493
to cover everything
Orders this month
706
at the current pace
Days of cushion
9,4
at that pace
This is the number to hold a risky decision against. A new hire, a bigger ad budget or a rent increase all shrink the cushion by their own size, and a store running under about a tenth of a month of safety has no room for an ordinary bad week.
Watch the cushion move, day by dayThe formula
Break-even says where the line is. This says how far you stand from it
Two stores can both be profitable and be in completely different positions. One clears its costs on the tenth of the month; the other clears them on the twenty-eighth. The second is one bad week from a loss, and no profit figure on its own will say so.
The cushion does. It is the share of today’s orders that could vanish before the month stopped covering everything, and converting it into days of trading turns an abstract ratio into something you can picture: a delayed shipment, a broken checkout over a long weekend, a supplier failing to deliver.
It is also the right frame for any new commitment. A hire, a rent increase or a bigger ad budget each shrink the cushion by a knowable number of orders, and the decision becomes whether what remains still survives an ordinary bad month.
Break-even here is found by the same routine the break-even calculator uses, so the two pages can never disagree.
Where it goes wrong
Four ways a cushion looks bigger than it is
A safety margin is only as honest as the costs underneath it, and these four all inflate it.
Measured against an average month
The cushion exists for the bad months, so compare it with your worst recent one rather than your typical one. A 20% cushion in a business whose weakest month runs 30% under average is not a cushion at all, it is a scheduled loss.
Costs that were not all counted
Every fixed cost left out of the block makes the cushion look larger: the annual insurance, the accountant, the app subscriptions, the salary you do not pay yourself yet. A cushion built on a partial cost list is arithmetic about a different company.
Ad spend quietly treated as variable
A committed monthly budget is fixed in every way that matters: it will be spent whether or not the orders arrive. Treating it as variable removes it from the block and can double the apparent cushion of a store that is spending heavily.
Read once, never again
The cushion moves with every price change, supplier increase and new subscription. It is a monthly reading, not a founding fact, and the useful version is the one you can watch trending in the wrong direction before it matters.
Worked example
The example store's cushion
The calculator’s defaults: €60.000 of net revenue across a €85 average order, goods at 38%, €6,40 of fulfilment and 1,9% of payment fees per order, €15.000 of ad budget and €7.000 of fixed costs over 30 days.
Each order contributes €44,68 after its own variable costs, and the block to cover is €22.000, so the month needs 493 orders and is doing 706.
A cushion of 213 orders on 706 is a margin of safety around 30%, which at this pace is roughly nine days of trading. The store could lose the best part of a week and a half and still cover everything it committed to.
That is also the frame for the next decision: a €2.000 monthly hire consumes about 45 orders of the cushion, leaving the store covered for an ordinary bad week but not for two.
Questions
The margin of safety, answered
What is the margin of safety?
The share of your current sales that could disappear before the month stops covering its costs. At 706 orders against a break-even of 493, the cushion is about 30%: roughly nine days of a thirty-day month could vanish before the store is into a loss. It is the single most useful number for judging how much risk a decision carries.
What is a healthy margin of safety?
It depends on how volatile your demand is, so the honest guidance is relative: a store whose worst recent month was 20% below its average needs a cushion bigger than 20%, or one ordinary bad month puts it into a loss. Anything under about a tenth of a month leaves no room for a broken ad account or a supplier delay.
How does this differ from break-even?
Break-even answers where the line is; the margin of safety answers how far above it you are standing. Both come from the same arithmetic, but the cushion is the one that makes a decision easy: a €2.000 monthly hire costs a known number of orders, and you can see immediately whether the cushion covers it.
Should ad spend count as fixed or variable here?
Both readings are defensible and they give different cushions, which is why it is an input. A committed monthly budget behaves like a fixed cost and joins the block to be covered. Spend that scales with orders comes out of each order's contribution instead. Most stores are closer to the budget answer than they assume.
Why express the cushion in days?
Because a percentage is abstract and a week is not. Nine days of trading is something an operator can picture: a delayed shipment, a broken checkout over a long weekend, a platform outage. Converting the cushion into time is what turns it from a ratio into a risk you can plan around.
More calculators
Four more, all free, all built on the same statement.
Want the long version rather than the arithmetic? Is my Shopify store profitable.
The terms this calculator uses:
Watch the cushion move day by day
nouz tracks the month against its own break-even from real orders and real costs, so the day the cushion starts shrinking is a thing you notice rather than a thing you reconstruct later.