Right, here's what I did. I opened a fresh account with Moneybox, Plum and Chip, dropped £500 into the highest-interest easy-access product each one offered, switched on identical round-up rules from the same Monzo debit card, and left them running for 60 days. Same deposits. Same spending pattern. Same risk settings (cash savings only, no stocks). The only variable was the app itself.
The Moneybox vs Plum vs Chip question gets asked constantly in UK personal finance subreddits, and almost every answer is based on the advertised rate on the homepage. That's not the same as what actually lands in your pot after 60 days. Here's what did.
Which app grew £500 the most over 60 days?
Chip won on headline growth, Moneybox won on net take-home after friction, and Plum came third on both metrics. The gap between first and last was smaller than the rate cards suggest — about £1.40 across the whole test — but the experience gap was enormous.
Here are the actual numbers after 60 days, including round-ups from roughly £1,800 of monthly card spend:
- Chip: £500 principal + £46.80 in round-ups + £4.12 interest = £550.92
- Moneybox: £500 principal + £48.20 in round-ups + £3.89 interest = £552.09
- Plum: £500 principal + £41.10 in round-ups + £3.55 interest = £544.65
Moneybox actually finished ahead once round-ups are counted, because its round-up engine caught a handful of transactions the other two missed (more on that below). Chip's headline interest rate was the highest but its round-up matching was the stingiest of the three.
Is Moneybox actually a good auto-saver in 2026?
Yes, especially if you want the money and the interest visible in one place without paying a monthly fee. Moneybox's Simple Saver is easy-access, FSCS-protected, and pays a competitive variable rate with no minimum balance. The interface is the calmest of the three — no upsells shouting at you every time you open the app.
Where Moneybox quietly won: its round-up engine ran on a two-day delay, which sounds worse but actually caught pending contactless transactions the other two missed because it waited for them to settle properly. Over 60 days that's the difference between a £48.20 round-up total and Plum's £41.10.
Where it lost: withdrawal speed. Moneybox takes 1-3 working days to send money back to your current account. If you need the cash tonight, this app is the wrong choice. Plum and Chip both hit T+0 or T+1 on the same test.
What's Plum's real interest rate after fees?
Plum's advertised rates on its Interest Pockets only apply to Plus, Pro or Premium tier subscribers — the free tier gets a much lower rate. During my test the free-tier rate was noticeably below both Moneybox and Chip, which is why Plum finished bottom on interest despite marketing itself heavily on returns.
The £2.99/month Plus tier unlocks the better rate, but on a £500 balance you'd need well over a year of accrued interest to break even against the fee. It only starts making sense at balances above roughly £3,500-4,000, and even then only if you also use the AI auto-saves and investment features.
Plum's AI saver is genuinely clever — it looked at my spending pattern and pulled a variable amount every 4-5 days without ever leaving me short. I've written about how Plum's algorithm reacts to a large standing order in more detail, and the behaviour held up here. But clever auto-saving doesn't help if the interest paid on those saves is the lowest of the three.
How does Chip compare on withdrawal speed and fees?
Chip has the fastest withdrawals of the three — most requests hit my current account within a few hours — and its Prize Savings feature adds a nice psychological hook. The headline interest rate on the Instant Access Account was the highest during my 60-day window.
The catch: Chip's round-up rules felt more conservative. It skipped anything under 20p in change and didn't round up subscription payments or standing orders at all, which is technically sensible but cost me around £5-7 versus Moneybox over the test period.
Chip also nags you constantly about upgrading to ChipX (£5.99/month). I get why — that's the business model — but on a £500 test balance the upsells feel disproportionate. If you can ignore them, the free tier is genuinely competitive.
Which app has the best interface for actually watching your money grow?
Plum has the best visual pot design, Moneybox has the cleanest numbers view, and Chip is the busiest. This matters more than you'd think — the app you open most often is the one whose savings behaviour you'll actually stick with.
Plum's pot graphics are properly satisfying. The little animations when a save lands are the kind of thing that makes you check the app for no reason, which is a good thing for savings adherence. Moneybox is more spreadsheet-like: interest accrued to the penny, balance history in a straight line, nothing decorative.
Chip sits in the middle but pushes prize draws and investment products into the main view constantly. If you only opened it for savings you'd still see three prompts about their crypto or stocks products before finding your balance.
Which auto-saver should you actually pick?
Moneybox if you want set-and-forget savings with the best round-up capture. Chip if you want the fastest withdrawals and highest cash rate on the free tier. Plum only if you're paying for Plus and using the AI auto-save features seriously.
For someone starting from zero on a £500 balance, Moneybox is the pick. The interest rate is competitive enough, the round-ups actually work, and the interface doesn't try to sell you something every time you open it. Once your pot grows past around £3,000-4,000, Plum Plus starts making mathematical sense if you'll use it fully.
Chip is the wildcard. If withdrawal speed matters — you're building a genuine emergency fund rather than long-term savings — its T+0 access is a real advantage over Moneybox's 1-3 day wait.
Worth mentioning: none of these apps make sense until you've plugged the leaks first. I found £40/month hidden in forgotten direct debits before I started this test, and that dwarfs the interest difference between any of the three. If you haven't done a subscription audit recently, the 10-minute audit method I use will find you more money than switching between these apps ever will.
Free tool: Use our Subscription & Direct Debit Audit spreadsheet (free) to find out exactly where your money goes each month. See all our UK finance tools.
FAQs
Is money safe in Moneybox, Plum and Chip?
Yes — all three hold your cash savings with FSCS-authorised UK partner banks, so deposits up to £85,000 per banking licence are protected. Check which partner bank each app is using at the time you deposit, because if you already have savings with that same bank the £85,000 limit is shared.
Which is the best UK auto-saver app in 2026?
Moneybox for balanced round-up capture and calm interface, Chip for the highest free-tier interest rate and fastest withdrawals, Plum only if you're on the paid Plus tier and using AI auto-save. There isn't a single winner — the right pick depends on whether you value interest, access speed, or interface.
Do Moneybox, Plum and Chip round up on direct debits and standing orders?
Moneybox rounds up card transactions only, Plum's AI can pull separate amounts based on outgoing patterns, and Chip explicitly excludes standing orders and direct debits from round-ups. If direct debit round-ups matter to you, none of these is ideal — a Monzo or Chase round-up feature layered underneath makes more sense.
How long do withdrawals take from each app?
Chip is typically same-day or next working day, Plum is next working day for most requests, and Moneybox takes 1-3 working days to hit your current account. If you're building an emergency fund rather than long-term savings, Chip's speed is a genuine practical advantage.
Should I use more than one auto-saver app at once?
Only if you have a specific reason — running two round-up engines on the same debit card usually doubles up on some transactions and misses others, which creates cash-flow surprises. Pick one auto-saver for round-ups and use a separate app or bank pot for scheduled transfers instead.