← Back to Robyn
30 Mins a Day · calculator & risk rules

30 Minutes a Day Calculator 🧮

Set your inputs to see position size and expected profit with the one loss rule and a twenty percent max loss. Everything updates as you type.

Your numbers

Start with the defaults, then change any box.

$
%
%

Rule of day management. You may take at most one loss per day, and the max loss per losing trade is twenty percent of the position size. Stop trading for the day if that max loss is hit.

Your results

Position per trade$0.00
Net four week profit$0.00
Profit per winning trade
$0.00
Loss per losing trade
$0.00
Gross daily profit from wins
$0.00
Daily loss from losing trades
$0.00
Net daily profit after losses
$0.00
Net weekly profit
$0.00
Net four week profit
$0.00

All results are before fees and taxes and for education only. Please consult with a qualified tax professional before making tax or business structure decisions. Profits are not guaranteed.

How the calculator works

  1. Pick your starting capital.
  2. Split that number evenly across how many trades you take in one day.
  3. Each win grows by your target percent.
  4. One loss per day is allowed, and it is capped at 20% of that trade.
  5. Stop for the day if you hit that one loss.
  6. The tool totals your day, your week, and your four week results before fees and taxes.

Simple rules to follow

  • Use only capital set aside for this strategy.
  • Aim for small wins often, not big home runs.
  • Two wins beat one loss most days when you keep the loss small.
  • If you break the one loss rule, your math breaks too.
  • Keep notes so you can see what works and repeat it.
SPY same-day (0DTE) contracts

Contract price guide

What Tiffany teaches about contract prices: what a good price looks like, what pricey looks like, and why it changes during the day. Prices are per share; one contract is 100 shares, so a $0.50 contract costs $50.

Sweet spot
$0.25 – $0.60

About $0.25 to $0.60, depending on the time of day. That's $25 to $60 a contract.

Good price
The line
Under $1

Keep contracts under $1 ($100 a contract). Under $1 is the guideline.

Still OK
Pricey
~$2

Morning contracts often run around $2 ($200 each). Your money buys fewer contracts.

Pricey

By time of day

The same contract gets cheaper as the day goes on because of theta (time decay): a same-day option loses value every minute it gets closer to the close.

Morningaround ~$2 ($200 each)Middaygetting cheaperLater in the daycheaper · about $0.25–$0.60

Check a price

Type the contract price you see. Uses your position per trade from the calculator above.

$
Type a price to see where it lands.

Check the spread

Aim for under about 10% between the bid and the ask, and try to fill near the middle.

$
$
Type the bid and the ask.

Education only. Not financial advice. This calculator and price guide are educational tools from Tiffany's 30 Minutes a Day class. Nothing here is a recommendation, an offer, or advice to buy, sell or hold any security or option. We are not a broker, dealer or registered investment adviser.

Results are math on the numbers you type, before fees and taxes. Profits are not guaranteed, and past results never promise future results. Options can lose 100% of what you put in. You decide every trade and accept the risk. Please consult with a qualified tax professional before making tax or business structure decisions.

Robyn 1.3 · Beta.