Form B deadline 2026: 30 June, and what late costs.

Not sure if you're a Form B person?

One rule: any business income at all puts you on Form B, even if you also have a salary. Employment income only? You were a Form BE filer and your deadline (15 May) has already passed. If that's you, read this next. Still unsure which form is yours? Form B vs Form BE, settled in 30 seconds.

Does the deadline also apply to paying the tax?

Yes, and this is the part that catches people. The balance of tax for YA 2025 is due by the same deadline as the form. Filing on time but paying late still triggers the Section 103 surcharge: a flat 10% on whatever is unpaid. It stays at 10% however long it drags on, because the old further 5% after 60 days was repealed with effect from 1 January 2020. If your number looks big, knowing it a few weeks early is the difference between planning cashflow and eating a penalty.

What happens if I miss the Form B deadline?

Two separate hits. Late filing: LHDN's administrative penalty under Section 112(3) is a percentage of the tax you owe, based on how late you are, 15% up to 12 months, 30% over 12 to 24 months, 45% beyond (the full Section 112 detail). The RM 200 to RM 20,000 you may have seen is the court maximum, reserved for prosecutions, not the everyday penalty. And if you don't file at all, LHDN can estimate your income themselves and add up to 300% of the tax (the best-judgment assessment). Late payment: the flat 10% surcharge above. If you've already missed it, file anyway, today. The penalty climbs at the one-year and two-year marks, and a voluntary late filing is treated far more gently than a discovered one.

Filing as a partnership?

The partnership files Form P by the same 30 June / 15 July dates, and issues each partner a CP30 showing their share of the profit. Each partner then reports that share in their own Form B. The CP30 figure is the net share. You don't re-deduct the partnership's expenses on your personal form.

What to have ready before you sit down to file

Your gross income per client or platform, your deductible business expenses (with receipts), capital allowance items like laptops and equipment, your personal relief receipts, and last year's form if you have one. LHDN can normally go back 5 years (and with no time limit where there is fraud, wilful default or negligence), and the law makes you keep the records for 7 years, so they need to live somewhere safer than a shoebox, missing records is itself a fineable offence.

The RM 200 to RM 20,000 Section 112 fine sits on top of this only if LHDN takes you to court, which they reserve for people who never file at all, not for an ordinary late filer.