My closed profit and loss was green that afternoon. I remember looking at it and thinking the day was fine — I was down $800 on closed trades, the daily limit was $5,000, I had room. Then all three of my open trades went against me at once, the stops slipped on a spike, and the breach email arrived before the charts had even finished moving. My closed P/L was a story I told myself. The firm measured equity, and equity counts your floating losses.
In this article
That is why I built the Floating Loss Drawdown Calculator at the top of this page. You give it your start-of-day equity, today’s closed P/L, and up to three open trades with their stops. It works out the worst case — every stop filling at once, with the slippage you allow — and tells you how far that worst case sits above or below the daily floor. Let me explain the maths, then show you the afternoon I wish I had run it.
Why closed profit can lie to you
Most prop firms define the daily limit on balance plus floating at some point in the day. Your platform’s “profit” column shows closed trades. Your firm’s risk engine watches equity. When your open trades are red, equity is lower than your closed P/L suggests, and the gap is exactly the drawdown you are ignoring.
The second trap is the stop itself. A stop is a plan, not a fill price. On a fast move your stop fills beyond its level, so the loss you planned is not the loss you get. I stress every open stop with a slippage allowance — 50% by default — because planning for the fill I want instead of the fill I get is what cost me that afternoon. For how the base limit is measured, read prop firm max daily drawdown explained.
The worst-case maths
The calculator adds up the risk sitting in your open trades, stresses it with slippage, and subtracts the whole lot from your start-of-day equity alongside today’s closed result.
| Variable | What it is | Typical value |
|---|---|---|
| Start-of-Day Equity | Balance plus floating at the firm’s reset time | Your account size on day one |
| Closed P/L | Today’s finished trades, wins minus losses | -$800 in my example |
| Slippage % | How much worse than planned your stops might fill | 25% – 100% |
| Gap above floor | Worst-case equity minus the daily floor | Positive is safe, zero is the edge |
The verdict follows the gap. SAFE means even the stressed worst case keeps you above the floor. CAUTION means the worst case has eaten most of the day. DANGER means the worst case breaches the floor — the email I got. The bar shows what share of the daily limit the worst case has used.
Three open trades on a $100,000 account
Here is the afternoon reconstructed, with the numbers I should have checked at 2pm instead of 4pm. Account $100,000, 5% daily limit, start-of-day equity $100,000, closed P/L -$800, slippage allowance 50%.
| Step | Calculation | Result |
|---|---|---|
| Trade 1 stop risk | 0.5 lots × 20 pips × $10 | $100.00 |
| Trade 2 stop risk | 0.3 lots × 15 pips × $10 | $45.00 |
| Total open stop risk | $100 + $45 | $145.00 |
| Stressed open risk | $145 × 1.50 | $217.50 |
| Worst-case equity | $100,000 − $800 − $217.50 | $98,982.50 |
| Daily floor | $100,000 − $5,000 | $95,000.00 |
| Gap above floor | $98,982.50 − $95,000 | $3,982.50 (SAFE) |
This reconstruction is SAFE — the worst case uses about 20% of the daily limit. My real afternoon was worse, but the point stands: I finally had a number for the danger instead of a feeling about it.
Using the floating loss calculator step by step
Fill the fields at the top of this page, then press Calculate.
| Input field | What to enter | Sample figure |
|---|---|---|
| Account size ($) | Your starting balance | 100000 |
| Daily loss limit (%) | Your firm’s per-day ceiling | 5 |
| Start-of-day equity ($) | Equity at the reset time, floating included | 100000 |
| Closed P/L today ($) | Finished trades only, negative if you are down | -800 |
| Slippage allowance (%) | Extra loss beyond planned stops | 50 |
| Trade 1 lots / stop (pips) / pip value ($) | Your first open position | 0.5 / 20 / 10 |
| Trade 2 lots / stop (pips) / pip value ($) | Your second open position | 0.3 / 15 / 10 |
| Trade 3 lots / stop (pips) / pip value ($) | Your third open position, or zeros | 0 / 0 / 10 |
Everything is calculated in your browser, and nothing is stored.
Slippage is a cost, not an accident
I used to treat slippage as bad luck. It is not. It is a regular cost that arrives exactly when you can least afford it — on fast moves, which are also the moves that take out several stops at once. That is why the calculator stresses the sum of your stops rather than each trade alone. Three small stops hit together with slippage is one big loss wearing a disguise.
My routine now: before adding any position, I run the calculator and ask whether the worst case leaves me comfortable, not merely alive. If the verdict is CAUTION, I skip the trade or tighten something first. Around red news I flatten or double the slippage allowance — see news trading and daily drawdown. I also check the Trading Cost and Drawdown Calculator on busy days, and the Forex Factory Economic Calendar for what is coming.
Questions traders ask about floating loss and drawdown
Do prop firms count floating losses toward the daily limit?
Almost always yes, at least at some point in the day. Most firms measure the daily limit against equity, which includes open floating profit and loss. Never assume only closed trades count — check your firm’s rulebook for the exact wording.
How much slippage should I allow in the calculation?
I use 50% as a baseline and 100% around major news or on thin symbols like gold. If your broker regularly slips your stops by a pip or two on normal days, measure that for a week and set the allowance from your own data.
Why does the calculator assume all stops fill at once?
Because correlated trades lose together. If your three positions are all dollar shorts, one dollar spike stops all three. Assuming the worst case together is the only assumption that has ever saved me money.
What does the gap above the floor tell me to do?
It is your real remaining budget. If the gap is smaller than one more planned loss, you are done for the day whether you feel like it or not. I close up and walk away when the gap drops below twice my normal risk.
My closed P/L is positive but the verdict is CAUTION. How?
Because your open risk is bigger than your closed win. A +$300 closed day with $2,000 of stressed open risk is a -$1,700 day waiting to happen. The calculator shows you the day you are actually holding, not the day you have banked.
