Investing Frequency Calculator

Does investing frequency actually matter?

Yes, but probably less than you'd think, and in a different way than most people assume. Investing more often puts your money to work sooner: every dollar invested today earns returns from today, not from whenever the year wraps up. That head start on compounding adds up. But in Australia, where a lot of brokers charge a flat fee per trade, investing too often can end up costing you more in brokerage than you gain from the earlier start. The right frequency depends on your contribution size and which broker you're using, which is exactly what the calculator above, and this page, help you work out.

The dollar difference: weekly vs fortnightly vs monthly vs annual

Here's a clean, comparable example: $10,000 invested per year across all four frequencies, at an 8% annual return, over 10 and 20 years. The same total amount goes in each year, the only thing that changes is when it arrives in the market.

Gap between weekly and annual after 10 years: about $8,060.

Gap between weekly and annual after 20 years: about $35,320. Two things stand out. First, the gap between weekly, fortnightly and monthly is tiny. Weekly only beats monthly by $540 over 10 years, and $2,270 over 20. Second, the real gap sits between any kind of regular investing and dumping it all in as a single annual lump sum. That's the comparison worth caring about.

Why the gap exists: time in the market, explained simply

Think of it like planting seeds. Every dollar you invest starts growing the moment it hits the ground. A dollar invested in January gets 12 months to grow before December. A dollar invested in December barely gets any. When you invest annually at year-end, every dollar from that year sits in your bank account earning next to nothing while the market, on average, keeps climbing. Invest weekly instead, and your first contribution of the year gets 51 extra weeks of compounding compared to the lump sum investor. Your second gets 50. And so on. Add that up across a decade and you land on roughly $8,000 for a $10,000/year saver. Let it compound on itself for another decade and it more than quadruples.

The difference between weekly and monthly is small because the timing gap between them is small. A weekly investor just gets their money in a few weeks earlier than a monthly one. Real, but not dramatic. The big win is simply getting money into the market regularly, rather than sitting on it all year.

Match your frequency to your pay cycle

Fortnightly pay is the most common cycle in Australia. Weekly is common in trades and hospitality, monthly leans more corporate and professional services. This matters more than the maths above suggests, because the best investing frequency is the one you'll actually stick to, and the easiest schedule to stick to is the one that mirrors when money lands in your account. Investing on payday means the money moves before it has a chance to drift into discretionary spending, you skip the "what's left over" calculation entirely, and you remove the temptation to time the market because the decision is already made.

If you're paid fortnightly, invest fortnightly. Weekly pay, weekly works. Monthly pay, monthly's fine. The compounding difference between these is small. The behavioural difference between "automated on payday" and "manually whenever I remember" is enormous, and it's the bigger lever by far. If you haven't opened a brokerage account yet, our guide to starting to invest in Australia walks through setting up an account and placing your first order, including auto-invest options that can run on your payday without you lifting a finger.

The brokerage fee reality check

This is the part most investing-frequency articles skip. In Australia, brokerage fees are real, and they interact directly with how often you invest. Roughly what the major brokers charge per trade:

Run the brokerage maths on $10,000/year at Selfwealth's $9.50 a trade: 52 weekly trades costs about $494 a year in brokerage, 12 monthly trades costs about $114. That's roughly $380 more a year to invest weekly instead of monthly, or $3,800 over a decade. Remember the compounding advantage of weekly over monthly was only $540 over 10 years. The brokerage cost is seven times the benefit. On Pearler's $6.50 flat fee the gap narrows but still outweighs the compounding edge, and on a free-brokerage platform for ASX trades, the fee problem disappears and weekly investing wins cleanly.

The practical rule: keep brokerage under 0.5% of each trade. At $9.50 a trade that means each contribution should be at least $1,900. At $6.50, at least $1,300. At $29.95, at least $5,990. If your per-trade amount falls below that, invest less often until it doesn't. For more on picking a platform in the first place, see our broker comparison checklist.

This is dollar cost averaging, whether you meant to or not

Investing a fixed amount at regular intervals, regardless of what the market is doing, is dollar cost averaging by definition. Every Australian investing a set amount weekly, fortnightly or monthly into an ETF is already doing it. More frequent contributions buy at more different price points, which smooths your average cost a little in a volatile market, but for long-term investors in diversified funds that smoothing effect matters far less than simply getting your money into the market sooner and keeping it there. Our dollar cost averaging guide goes deeper on the honest trade-offs, including the cases where a lump sum actually wins.

The practical summary: which frequency should you actually pick?

• Low or no-fee broker: invest as often as your pay cycle allows. Weekly or fortnightly. The compounding edge is real and fees aren't eating it.
• Flat fee around $6.50-$9.50 a trade: fortnightly or monthly, aiming for at least $1,300-$1,900 per contribution to keep brokerage under 0.5%.
• Higher fee, around $20-$30 a trade: monthly at minimum, and ideally only once your trade size clears $3,000-$6,000. Worth comparing brokers if you're investing smaller amounts regularly.
• Irregular income: don't force a weekly schedule you can't sustain. Set a minimum monthly amount you can always commit to, then invest any surplus separately when it turns up.

The most important decision isn't weekly versus monthly. It's investing regularly, automating it, and not stopping when the market drops. Get that right and the frequency you land on barely moves the needle by comparison.