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What would a crash actually cost you?
Most portfolio tools tell you what you hold. This one tells you what happens to it when the market breaks. Enter your allocation, pick a real crash, and see the damage in dollars - no account, no API keys, and your allocation never leaves your browser.
1. Your portfolio
Enter it in dollars, or switch to percentages. No prices are fetched and your numbers are never sent anywhere.
Paste your holdings instead
2. What happens
Real events, measured from daily closing prices. Pick one.
More scenarios (9)
3. What it would cost you
The largest deleveraging event in crypto history: about $19B liquidated in a day. BTC touched roughly $102k from $123k intraday and closed about 9% down; the long tail closed two to four times lower than that.
Your mix falls 10.1% where bitcoin fell 9.0%. That is roughly in line with the event itself.
By value: 80% measured from its own history, 20% held at its peg.
Worst day in the event, 2025-10-11 - you $23,366 (-6.5%), BTC only $24,198 (-3.2%)
The headline applies the scenario's move to what you hold today. This line replays the whole window, including whatever the market did in the run-up, so its worst day and the headline are not the same number. It continues past the event to 2025-11-10 to show what came back.
Where it goes
Portfolio score
- Custody & counterparty42 → 43
Not scored here: volatility, target drift - these need your real history, which the app has and this page does not.
Already true of this portfolio
- 78% sits in Layer 1. Holdings in the same sector tend to fall together, so this is less diversification than the asset list suggests.
- BTC is 40% of your portfolio. Trimming it or adding other positions cuts single-asset risk.
- 64% sits with Hardware wallet. Spreading across venues or self-custody shrinks the blast radius if it fails.
Run this against your actual portfolio
Connect read-only exchanges and wallets and the same engine names the account, the asset and the position behind the loss - measured from your own history instead of estimated from a sector. No manual allocation, no API keys with trade permission.
What a stress test tells you that a portfolio tracker does not
A tracker answers “what do I have?”. It will happily tell you that your largest position is 47% of the portfolio, that 68% of it sits on one exchange, and that your annualised volatility is 74%. All three are facts, and none of them is a decision.
A stress test converts those facts into a number you can act on: if this happens, you lose this much. That reframing matters most in the cases people systematically misjudge - a portfolio spread across a dozen tokens that all fall together, or one whose real risk is not the market at all but the single venue holding most of it.
What each scenario actually replays
Historical scenarios replay what assets actually did, measured from daily closing prices in the same price store the product runs on. Figures are close-to-close and measured from the day before the event to the worst close inside it, so a window that happens to include the bounce still reports the fall rather than the recovery. The two alt seasons are the same rule pointed the other way - measured to the best close inside the window, because an upside event measured to its worst day would report the one red Tuesday in the middle of a four-month run.
- 10 Oct 2025 flash crash Downside bitcoin -9%
- The largest deleveraging event in crypto history: about $19B liquidated in a day. BTC touched roughly $102k from $123k intraday and closed about 9% down; the long tail closed two to four times lower than that.
- FTX collapse (Nov 2022) Downside bitcoin -24.5%
- An exchange holding customer funds went from solvent to bankrupt in under two weeks. The market fell with it, and everything still on the venue was gone.
- LUNA / UST collapse (May 2022) Downside bitcoin -18%
- An algorithmic stablecoin lost its peg and its backing token went to essentially zero in five days, taking the wider market down with it.
- USDC depeg (Mar 2023) Mixed bitcoin +18.4%
- A bank failure stranded part of the reserves behind USDC and it traded near $0.87 for a weekend. The lesson was that "cash" in a portfolio is still somebody's liability.
- Covid crash (Mar 2020) Downside bitcoin -39.5%
- A global liquidity panic took bitcoin down about 40% between closes - more than half of it intraday - and correlations across every asset class went to one.
- Tariff shock (Apr 2025) Downside bitcoin -8.6%
- Crypto traded as a risk asset on a macro headline, falling with equities rather than acting as a hedge against them.
- Alt season (Jan-May 2021) Upside bitcoin +119.8%
- The one everyone means by the phrase. Bitcoin roughly doubled and the long tail did multiples of that; in the last month bitcoin was already falling from its April top while altcoins kept running, which is what an alt season actually looks like.
- Alt season (Nov-Dec 2024) Upside bitcoin +56.3%
- The recent one: bitcoin broke $100k for the first time and the money rotated outward behind it. The majors gained, and the assets that had sat still for three years gained several times more.
Market scenarios
These are not historical. You set what bitcoin does and every other holding responds according to how it has actually behaved against bitcoin, so the long tail falls further than the majors - which is what every real crash has done.
- BTC -30%. An ordinary bear-market leg. Not a crisis; this happens.
- BTC -50%. A cycle drawdown. Every past cycle has had at least one.
- BTC -70%. A full bear market, peak to trough. The 2018 and 2022 bottoms both got here.
- Alt season (modelled). The upside case as a dial rather than a date: BTC grinds higher and the long tail runs harder. For the measured version, replay Jan-May 2021 or Nov-Dec 2024.
Exchange failure
The scenario no equities tool has an equivalent for, and the one this product is unusually well placed to answer. Nothing about the market changes: prices stay exactly where they were, and the balances sitting at one venue simply stop being yours. If that number surprises you, it is the most useful thing on this page.
How each holding's response is worked out
In order, most reliable first, and the tool labels every line with which one it used - so an estimate never reads as a measurement:
- Its own measured history. What that asset actually did over that window, from daily closes.
- Its measured beta. How much it has historically moved for each 1% bitcoin moved, over the trailing year.
- Its sector and size. A documented estimate, because an unranked memecoin and a mega-cap layer 1 do not fall together.
- Nothing. If we cannot honestly estimate a holding, it is left untouched and counted as unmeasured rather than quietly scored as a 0% move.
Stablecoins are held at their peg and only move under the depeg scenario. Wrapped and staked tokens follow the asset they are a claim on, so wrapped bitcoin falls with bitcoin instead of counting as a second, independent position. No holding falls past -100%: a beta of 1.6 against a 70% fall works out to -112%, and you cannot lose more of a coin than you own.
Measured history covers 255 assets, built on 2026-09-12. Anything outside that set falls to the estimate rungs above, and the tool says so.
What this page cannot do
It only knows the allocation you typed. Connect your exchanges and wallets to the app and the same engine runs against your real positions - measuring your own holdings' history rather than estimating from a sector, scoring the pillars that need price history, and letting you draft hypothetical trades to see whether they would actually have helped.
See where it goes.
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