First 90 Days Cash Flow Simulator
Most people entering cross-border commerce model margin, not cash. But a product with a healthy margin can still lock up a business by week six, because stock is paid today and the money arrives weeks later. This simulator shows exactly that gap.
Currency doesn't matter — keep every field in the same one. The simulation runs weekly across 13 weeks (≈90 days).
Cash trough
59.020
Cash bottoms out in week 9 and never goes negative.
Cash, week by week
| Week | Sold | In | Out | Cash | |
|---|---|---|---|---|---|
| 1 | 5 | 0 | 6.000 | 121.000 | |
| 2 | 8 | 0 | 6.000 | 115.000 | |
| 3 | 12 | 2.900 | 6.000 | 111.900 | |
| 4 | 15 | 4.640 | 6.000 | 110.540 | |
| 5 | 18 | 6.960 | 6.000 | 111.500 | |
| 6 | 22 | 8.700 | 6.000 | 114.200 | |
| 7 | 25 | 10.440 | 6.000 | 118.640 | |
| 8 | 28 | 12.760 | 6.000 | 125.400 | |
| 9↻ | 32 | 14.500 | 80.880 | 59.020 | |
| 10 | 35 | 16.240 | 6.000 | 69.260 | |
| 11 | 38 | 18.560 | 6.000 | 81.820 | |
| 12 | 42 | 20.300 | 6.000 | 96.120 | |
| 13! | 20 | 22.040 | 6.000 | 112.160 |
↻ restock ordered · ! demand exceeded stock · red rows are weeks where cash goes negative
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How it's calculated
The simulation runs weekly across 13 weeks (≈90 days). At week zero, setup costs and the first stock order come out of your capital — for many launches the lowest point happens before a single sale.
Weekly demand ramps linearly from week 1 to week 13. Real sales are never that smooth, but it's a reasonable average for capital planning. Sales are capped by stock: if demand exceeds inventory, the excess is lost and the week is flagged as a stockout.
Payout delay is the critical parameter. Revenue lands N weeks after the sale, not in the week of it. Amazon pays roughly fortnightly; some marketplaces take longer. Ads, meanwhile, are paid every week. That asymmetry is what strains the business.
Restocking is modelled automatically: when inventory can no longer cover the lead time, an order is placed and paid that week, arriving after the lead time. Because the second order is usually paid before the first sales have been paid out, this is what creates the real trough in most scenarios.
Outputs: the cash trough and its week, the week your capital is recovered, cash at week 13, and stockout weeks. If the trough is negative, that gap is precisely the capital you're missing.
What people most often forget
- The second stock order. Most people budget the first and not the second. If sales go well the second is bigger and gets paid before the first payout lands — growth killing cash, the classic way.
- A stockout costs more than that week's sales. Rank drops, recovery takes weeks, and ads cost more throughout.
- Returns and reserves. Marketplaces may hold back part of a payout against returns. Don't set the payout delay optimistically.
- Setup costs never really end: samples, packaging revisions, new photos and certification renewals all surface in the first 90 days. Add a 20% buffer.
- Cutting ads doesn't fix a cash problem. Sales fall, and cash inflow falls further behind. The usual right move is a smaller stock order, not zero ads.
Scope, sources and freshness
This is a scenario tool, not a forecast: it shows the cash consequence of your assumptions, not what your sales will be. The ramp is linear; seasonality, promotional periods, currency moves and tax payments are out of scope. Currency doesn't matter — keep every field in one unit. Review the output with your accountant before committing capital.
Sources last reviewed: 14 August 2026
Frequently asked
How much capital do I need to start?
There's no single figure — it depends on unit cost, first order size, payout delay and ad budget. Run the tool with your own numbers: if the cash trough goes negative, that gap is the capital you're missing.
Why 13 weeks?
Roughly 90 days is when a launch gives its first honest signal and the second stock decision has to be made. The cash squeeze usually happens inside that window.
What payout delay should I enter?
Two weeks is a reasonable starting point for Amazon. Elsewhere it varies by payment provider. When unsure, be pessimistic — overestimating by a week is far cheaper than underestimating by one.
Does it predict my sales?
No. You supply the sales assumptions; the tool computes their cash consequence. Run an optimistic and a pessimistic scenario to get a range.
I'm profitable but have no cash — how?
Profit is an accounting outcome; cash is a timing outcome. If you pay for stock today and get paid in three weeks, growing ties up more cash. That's exactly how profitable businesses fail.
If your product is ready, let's talk about the rest.
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