How Big a Bankroll Do You Need? Variance, Drawdowns, and Staking

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The right bankroll depends on what you’re doing. Converting promos, running arbs, and betting +EV all use money differently. This guide explains how much each needs, why, and how to size bets so a bad run doesn’t end your plans.

A ground rule first: your bankroll should be money you can afford to lose, set aside from bills, savings, and emergencies. Never borrow to fund it.

Promo conversion: working capital

When you hedge a bonus bet, the outcome is locked in. Your money isn’t really at risk, but it’s tied up until the game settles. What you need is enough working capital to place the hedge.

The hedge for a bonus bet grows quickly with the promo odds:

These figures assume a tight pair of prices. See bonus bet conversion rates.

You also need money to meet qualifying bets and deposit minimums across several books, and some will sit in accounts for days while bets settle and withdrawals process.

A practical starting point: $1,000 to $2,500. That covers most welcome offers at good conversion rates. With less, you can still convert by using shorter odds or splitting bonuses, at a lower rate.

Arbitrage: capital spread across books

Arbs appear and disappear in minutes, and each leg sits at a different sportsbook. You can’t wait for a deposit to clear, so money has to already be in the right accounts.

• Keep $300 to $1,000 in each account you arb with, depending on your typical stake.
• Rebalance weekly: winning books accumulate money, losing books run dry.
• Expect some capital to be idle at any time.

A modest arb operation across eight books might need $3,000 to $6,000 in total. The returns (0.5% to 3% per arb) are small relative to that capital, so turnover is what drives profit. See our arbitrage guide.

+EV betting: risk capital

+EV bets aren’t hedged. You win some and lose some, and your edge shows up over thousands of bets. The bankroll here is genuine risk capital, and it has to absorb variance.

What variance looks like

Over 1,000 even-money bets, a run of 9 or 10 straight losses is normal. So are stretches of 100 bets where you’re down, even with a solid edge. Our +EV guide shows that a bettor with a 3.5% edge is still behind after 1,000 bets about one time in seven.

Sizing bets for variance

The standard tool is the Kelly criterion, used at a fraction:

• Quarter Kelly on market-based edges usually means stakes of 0.5% to 1.5% of bankroll.
• A hard cap of 2% to 3% of bankroll per bet protects against overconfidence.
• Expect drawdowns of 20% to 30% from peak even at these sizes. Plan for them in advance.

How big should a +EV bankroll be?

Work backward from your typical stake. If you want to bet $50 per bet at about 1% of bankroll, you need roughly $5,000. If you only have $1,000, bet $10 to $15 until your bankroll grows.

Run the numbers: How much of my bankroll should this edge get? Open the Kelly Criterion Calculator

Combining strategies

Many people do all three in stages:

1. Start with promo conversion. It needs working capital, not risk capital, and builds your bankroll with little variance.
2. Add arbs as they appear at books you already hold.
3. Move into +EV once you have a bankroll that can absorb swings, and promos have slowed down.

Keep separate records for each so you know where your profit actually comes from.

Rules that keep you in the game

• Separate your bankroll from everyday money. A dedicated bank account helps.
• Don’t raise stakes after losses to “get it back.” That’s how bankrolls die.
• Recalculate your bankroll after big swings and size bets from the current figure.
• Withdraw profits regularly. Money sitting at a sportsbook isn’t doing anything for you.
• Set aside money for taxes. From 2026, federal rules only allow 90% of gambling losses to be deducted, which can raise your tax bill. See sports betting taxes in 2026.
• Know when to stop. If betting stops feeling like a controlled, mathematical process, take a break. Our responsible gambling page lists free, confidential help.