Film reel guide
How to Measure Film Reels
Reviewed August 7, 2026 · Analog Rescue data editor
The short answer
Measure straight across the outside edges of the reel—not from the center hub to one edge. The diameter gives a maximum footage estimate, but a partly filled reel contains less film. Use the estimate for planning and expect the provider to confirm the footage it actually scans.
Estimate the cost of your reelsMeasure each reel in three steps
- Lay the reel flat on a stable surface without pulling or unwinding the film.
- Measure the full outside diameter from edge to edge through the center hub.
- Round to the nearest standard reel size and note whether the reel is full, partly full, or nearly empty.
Common reel sizes and maximum footage
| Outside diameter | Typical maximum footage | Planning note |
|---|---|---|
| 3 inches | 50 feet | Small home-movie reel |
| 4 inches | 100 feet | May be priced as a small reel or by the foot |
| 5 inches | 200 feet | Common home-movie reel |
| 6 inches | 300 feet | Check provider size support |
| 7 inches | 400 feet | Large home-movie reel |
Why diameter is only an estimate
The size stamped on a reel describes its capacity, not how much film is actually wound onto it. Leader, empty space, a smaller center hub, and partially filled reels all affect the real footage. Per-foot services should charge from measured footage; reel-size services may charge by the reel tier.
Keep your own reel count and diameter notes. They make it easier to compare the provider's invoice with the estimate.
Do not measure by unwinding the film
Unwinding adds handling risk and is unnecessary for a planning estimate. Leave brittle, warped, spliced, or unusually dirty film on its reel and ask the provider whether inspection, cleaning, or repair is included.
Editorial version editorial-2026-08-07. See our editorial standards and comparison methodology.