ModelCalcs.uk
Track Length Calculator — Layout Planning
Calculate total track length needed for your model railway layout plan including sidings.
How We Calculate This
Calculates main line track length from your baseboard dimensions and track plan style, then adds siding lengths. The oval is treated as a stadium shape (a discorectangle): two semicircular ends joined by two straights, the largest curve that fits the board width.
Formula
- Curve radius r = ½ × Width (floored at the gauge minimum: OO 438mm, N 228mm, O 876mm)
- Each straight = Length − 2r (the curved ends use up the curve diameter)
- Oval main line = 2 × Straight + 2 × π × r (the two semicircles make one full circle)
- Sidings total = Number of sidings × Average siding length
- Total track = Main line + Sidings total
- Flex track pieces = Total ÷ 914mm (Peco Streamline, OO and N)
Figure-of-eight, dogbone, point-to-point and complex multi-track are rough planning estimates — always confirm against a scale track plan and add 15-20% for cutting and adjustments.
Frequently Asked Questions
A basic OO gauge oval on a 6x4 foot (1800x1200mm) board needs about 5 metres of track. Adding a passing loop and siding brings this to 7-8 metres. Always buy 10-15% extra for adjustments and mistakes.
Peco Streamline flex track comes in 914mm (36 inch / one yard) lengths in both OO/HO (SL-8300, SL-100) and N gauge (SL-300, SL-300F) — they are the same length. Other brands differ: Atlas N is about 749mm and Kato N about 808mm. You can cut flex track to any length with rail cutters. Set-track curve and straight pieces vary by manufacturer.
Buy 15-20% more than your calculated need. Track gets cut when fitting curves, mistakes happen, and you will likely add extra sidings as your layout develops. It is cheaper to buy in bulk than to reorder single pieces.
OO gauge (1:76, 16.5mm track) is the most popular in the UK and suits layouts 6x4 feet and larger. N gauge (1:148, 9mm track) is ideal for smaller spaces — you can fit a full layout in 4x2 feet. OO9 and narrow gauge suit branch line themes.
Related Calculators
Ballast Calculator
Calculate ballast volume and weight needed for model railway track sections.
Platform Length Calculator
Calculate scale platform length based on train lengths and number of coaches.
Tunnel Calculator
Calculate tunnel bore dimensions, portal size and minimum length at scale.
Baseboard Calculator
Plan baseboard dimensions, support spacing and materials for your layout.
Model Railway Wiring Calculator
Calculate bus wire length, dropper count, dropper wire and power supply sizing for model railway layouts.
Was this calculator helpful?
Last updated: February 2026
All calculations are estimates. Always verify quantities before purchasing materials.