Work From Home Electricity Cost Calculator — Actual vs HMRC Flat Rate

HMRC allows employees and the self-employed to claim £6 per week (£312 per year) for additional household costs when working from home, without providing evidence. This is the 'working from home relief' flat rate. It can be claimed via self-assessment or, for employees, via PAYE through a P87 form.

Yes. You can claim actual additional household costs (electricity, gas, broadband proportion) instead of the flat rate. This requires detailed evidence — utility bills, calculations of the work proportion of each cost. Actual costs are only worth claiming if they exceed £6/week, which typically requires heating a dedicated home office for significant periods.

Calculate: (1) kWh used by work equipment (computer, monitor, printer etc.) × electricity rate per kWh, (2) Additional heating cost attributable to working from home (pro-rated by WFH hours as proportion of total room usage hours during heating months). Keep records of devices, wattage, and usage times.

The UK electricity rate in 2025/26 is typically around 24-25p per kWh (standing charge separate). The Ofgem price cap is reviewed quarterly. The exact rate depends on your supplier and tariff. Check your electricity bill for your exact unit rate.

Yes. Equipment purchased solely for work (desk, chair, monitor, webcam) is an allowable deduction for the self-employed or can be claimed by employees via their employer's expenses scheme. One-off items for exclusive work use qualify. Items with dual personal/work use are treated differently.

Employees can claim the WFH flat rate for weeks when they work from home. You don't need to work from home every day of the week — claiming for the weeks or days you work from home is acceptable. If your employer pays you WFH allowance, you can only claim the excess above the employer payment.

The WFH flat rate has been £6/week since April 2020 (when it doubled from £3). There's no announced increase for 2025/26. As energy prices have risen significantly since 2020, the flat rate has become less generous relative to actual costs. HMRC occasionally reviews these rates.

Generally no. HMRC does not allow claiming a proportion of mortgage or rent for home working, as the property is also your home and has personal use. Only the additional costs directly caused by working from home (electricity, heating, broadband) are potentially claimable.

If your employer reimburses WFH costs using HMRC-approved rates (up to £6/week or approved amounts), this is not taxable income for you. If employer pays more than the approved rate, the excess is taxable (subject to P87 or self-assessment). Claims for relief only arise where no reimbursement is made.

The proportion of broadband used exclusively for work can be claimed. However, most broadband is shared with personal use, making exact calculation difficult. HMRC may scrutinise large broadband cost claims. A reasonable approach: if broadband is essential for work and you have no other internet connection, you might claim part of it.

For income tax, you can claim WFH relief for the last 4 tax years. For the 2020/21 tax year (when COVID working from home began), HMRC provided special relief equivalent to £6/week for the full year. Check each year separately as the flat rate was £3/week before April 2020.

Keep: electricity bills showing unit rates and consumption, calculation showing how you apportioned business vs personal use (by time or other basis), details of all home office equipment used, contracts or employer correspondence confirming WFH requirement, and dates/hours of WFH. Self-employed claimants should include this in their self-assessment working papers.