Patent filing costs under the Patent Cooperation Treaty have changed in the UK from 1 January 2026. GOV.UK confirms a £75 transmittal fee, a £1,605 search fee, and an international fee of £1,242 for the first 30 sheets plus £14 for each sheet thereafter. There are e‑filing reductions of £187 or £280 depending on format, a £150 fee for restoration of priority, and £20 for a certified priority document.

For founders and finance leads, the upfront cash call is material. Kept within 30 sheets and filed in character‑coded format, the arithmetic is £1,242 for the international fee minus the £280 e‑filing reduction, plus £75 transmittal and the £1,605 search fee. That sets a baseline near £2,642 before any optional £20 priority document copy.

Length adds cost. A 45‑sheet filing carries 15 sheets over the 30‑sheet threshold, adding £210 to the international fee. If filed electronically but not in character‑coded form, the £1,242 base becomes £1,452, then drops by the £187 reduction; add £75 and £1,605 and the total lands around £2,945. Choosing character‑coded text would trim a further £93.

Heavier technical submissions move the needle again. At 100 sheets, the extra 70 sheets add £980, taking the international fee to £2,222. With character‑coded e‑filing, subtract £280, then add £75 and £1,605 for a working total around £3,622. The slope is clear: after 30 sheets, every extra sheet is £14.

The e‑filing reductions hinge on format. Character‑coded means the application body is submitted as machine‑readable text rather than only as a scanned PDF, which earns the larger £280 reduction. If your attorney’s workflow allows, supplying fully digital text is the simplest way to bank that saving.

Notice where the money goes. In a within‑30‑sheets filing, the £1,605 search fee is roughly 61 percent of the baseline outlay; in the 45‑sheet case it’s about 55 percent; at 100 sheets it’s closer to 44 percent as sheet charges grow. That split helps teams focus on both page control and filing format.

Timing still matters. Missing the 12‑month priority window is avoidable but, if it happens, GOV.UK lists a £150 restoration of priority fee. Build calendar prompts from your earliest priority date so restoration is a rarely used contingency rather than an expected cost.

Drafting discipline can reduce spend without sacrificing protection. Streamline repeated passages, avoid unnecessary boilerplate, and agree early with counsel how to keep the specification within 30 sheets. Every sheet beyond that threshold adds £14 to the international fee.

For budgeting, we’d earmark roughly £2.6k for a lean, within‑30‑sheets filing using character‑coded e‑filing, then add £14 per extra sheet and the optional £20 for a priority certificate if needed. If cash is tight, plan the filing in a month with surplus free cash flow and confirm with your attorney when each component becomes payable.

These figures come directly from the GOV.UK update dated 1 January 2026 and apply when filing via the UK Intellectual Property Office as Receiving Office. For companies planning global coverage this year, the practical playbook is simple: keep sheets tight, file in character‑coded format, and set a cash buffer before the filing date.