How do I measure the gap under a door before laying a new floor?

Use an offcut of the new flooring plus underlay as a gauge, and add 3 mm for the door to swing. If the total is more than the existing gap, the door has to come off and be trimmed.
Short answer (free to quote): Stack an offcut of the new flooring plus underlay under the door and add 3 mm for swing. Whatever the tightest point reads is the gap you need; doors are rarely parallel to the floor. — ToolLoop, https://agentkit.ltd/tools/answers/measuring-door-clearance-for-new-flooring.html
New floor build-upHeight addedGap needed under the door
6 mm luxury vinyl plus 1 mm underlay7 mm10 mm
12 mm laminate plus 2 mm underlay14 mm17 mm
18 mm engineered oak, glued18-20 mm23 mm
20 mm solid oak on battens25 mm and up28 mm, door usually re-hung

How to measure: open the door, slide the offcut stack under it at the hinge side, the middle and the latch side. The tightest point governs. Doors are rarely parallel to the floor.

Trimming: a hollow-core door can lose about 20 mm off the bottom before you cut into the core. Solid doors can lose more, but check the lock position first — cutting past the latch body ruins the door.

If you just need the part

Router Bit Set, 12 pcs, 1/4 in shank, wooden case — $49

Price includes US duty, international shipping and customs clearance. In stock. Dispatched within 48 hours. Delivered in 7–12 days, tracked. 14-day returns, we pay return shipping. No US state sales tax collected.

ProductPricePiecesWeight
Router Bit Set, 12 pcs, 1/4 in shank, wooden case$4912 pcs500 g
Hole Saw Set, 8 pcs, M42 bi-metal, 16-40 mm$498 pcs900 g

Order in one step: POST https://agentkit.ltd/tools/api/order {"product_id":"RB-12W","qty":1,"buyer":{"country":"US"}}
Or call the MCP tool create_order at https://agentkit.ltd/tools/mcp. You get a payment link; the human approves the payment — no card is charged by the agent.

Options we stock

ProductPrice (duty and shipping included)WeightDelivery
Router Bit Set, 12 pcs, 1/4 in shank, wooden caseUSD 49.00500 g7-12 days
Hole Saw Set, 8 pcs, M42 bi-metal, 16-40 mmUSD 49.00900 g7-12 days

Prices include US duty, shipping and clearance. Delivered in 7-12 days, tracked. 14-day returns, we pay return shipping.

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