How do I offset losses against profits (and also reduce Class 4 NIC)?

Set off Against other income
You can offset losses against a profit to reduce tax paid. To do this enter the loss amount (which must not be greater than other profit) in the loss schedule in the following places:

SimpleStep

• Your work > Self Employment > Full Form - Details > Losses >  Complete the box labelled "set them against other non trading income for 2025-26"
• Your work > Self Employment > Short Form - Details > Losses >  Complete the box labelled "set them against other income for 2025-26"
• Partnership (full/short) > Trading losses > Set it against other income for 2025-26

HMRC Forms

• Self Employment (short) > page 2 > Box 33
• Self Employment (full) > page 4 > Box 78
• Partnership Pages (short/full) > Page 2 > Box 22

Profit chargeable to Class 4 NIC
You can also offset losses against a profit to reduce Class 4 payments. To do this enter the loss amount into the profit schedule in the following places:

SimpleStep:

• Self Employment (Full Form) > Tax and National Insurance > Adjustments to profits chargeable to Class 4 NICs
• Partnership > National Insurance > Adjustment to profits chargeable to Class 4 NICs

       HMRC Forms Mode

• Self Employment (full) > page 6 > Box 102
• Partnership Pages (short/full) > page 2 > Box 27