UK Work From Home Costs — Actual vs Flat Rate Comparison
Compare whether the HMRC £6/week flat rate or the actual additional household costs method gives you more tax relief for working from home.
WFH Relief Comparison Guide
Flat Rate vs Actual Costs
HMRC provides two methods to claim working from home tax relief for employees. Flat rate: £6/week × weeks worked from home. Annual maximum (52 weeks): £312. No receipts needed. Self-assessment or P87 form. Actual costs: calculate the business proportion of gas, electricity, and other household running costs. Proportion = (rooms used for work / total rooms) × (hours working from home / total hours in week). Requires receipts and calculations. Only worth the effort if actual costs significantly ex
Actual Cost Calculation Method
Step 1: calculate room proportion = work rooms / total rooms. Step 2: calculate time proportion = WFH hours per week / 168 total hours in week. Step 3: multiply all household energy costs by both proportions. Heating cost attributable to WFH: £1,200 annual heating × (1/5 rooms) × (37.5/168 hours) = £1,200 × 0.2 × 0.223 = £53.57. Electricity similarly. Total actual additional cost: often £100-200/year. For most employees: this barely exceeds the £312 flat rate for a full year. Actual costs method
Broadband and Phone
Internet (broadband): if you need internet for work AND for personal use, HMRC will only allow the additional business cost. For most people: broadband would exist regardless — no additional cost attributable to WFH. Exception: if you upgraded to a faster plan specifically for work, the additional cost is claimable. Business telephone calls: actual cost of business calls only (not line rental). If employer provides a work mobile: use that, no personal phone cost claimed. These costs are generall
Self-Employed WFH
Self-employed people (sole traders) use different rules: simplified expenses method: 25-50 hrs/month: £10. 51-100 hrs/month: £18. 101+hrs/month: £26. Annual maximum (101+ hrs/month throughout): £312. Same as the employee flat rate on an annual basis. Actual costs: calculate business proportion of all household running costs. No restriction to specific amounts. Can include: rent or mortgage interest (proportion), council tax (proportion), repairs and maintenance (proportion). More generous than e
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