ETF top-up calculator
Which ETF should you buy this payday?
Enter your target mix and what you already hold. We'll work out exactly how many units to buy to get back on target, without selling anything.
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This payday, buy
Add your ETFs, targets and an amount to see exactly what to buy.
Get this worked out for you every payday
Free. We'll email your buy list on payday and keep a record of every purchase, with its date and price.
Prices are the last close. This is arithmetic on the targets you enter, not a recommendation.
1. Set your mix once
Pick the split you want, like 40% VAS and 60% VGS. Not sure which mix? Backtest a few first.
2. Get a buy list every payday
On payday we email exactly which ETF and how many units to buy, based on today's prices and what you hold.
3. Tap 'I bought these'
Your plan stays accurate and every purchase is recorded with its date, price and brokerage, ready for tax time.
Common questions
Why top up instead of selling to rebalance?
Selling units usually creates a capital gains tax event and costs brokerage. Putting each new contribution into whichever ETF is furthest below its target moves you back towards your mix without selling anything. This is how many Australian DIY investors keep a two- or three-ETF portfolio on track.
Should I buy one ETF or split my money?
With brokerage charged per trade, buying just the most underweight ETF each payday keeps costs down. Over a few paydays it has the same effect as splitting. If your brokerage is $0, splitting keeps you closer to target every time.
What's the $500 minimum?
Most CHESS-sponsored brokers need your first purchase of a new ETF to be at least $500. Later top-ups can be smaller. The calculator won't suggest a first buy below that.
Why keep a record of every purchase?
Each purchase is a separate parcel for capital gains tax, with its own date and cost. From 1 July 2027 the 50% CGT discount is replaced by inflation indexation and a 30% minimum tax, and the value of each parcel at that date affects how gains are split. Recording purchases as you make them saves reconstructing years of history later.
Is this financial advice?
No. The calculator does arithmetic on the target mix you choose. It doesn't recommend ETFs or allocations.
Still choosing a mix? See how VAS vs VGS splits have performed.
Important: This is general information and education only and doesn't take into account your objectives, financial situation or needs. It's not financial advice. Consider getting advice from a licensed financial adviser before acting.