How to Use This Calculator
Fill in the four setup fields to get an instant result — all outputs update live as you type. No "calculate" button needed.
- Reel size preset — choose a common reel/thickness combo; the tape length field fills automatically, or type any custom length.
- Tape speed (IPS) — select the IPS setting on your deck. 7½ IPS is the most common for home and semi-pro use.
- Track configuration — half-track stereo (the most common for home decks), quarter-track stereo (4-track; use double-sided to get two stereo passes), or full-track mono.
- Recording passes — single-sided records one pass. Double-sided flips the reel for a second pass (most quarter-track decks support this).
- Optionally enter the cost per reel and number of reels to see session cost and cost per recorded minute.
- Hit Print / Save PDF for a clean one-page result, or Copy CSV to paste into a spreadsheet.
Understanding the Core Formula
Recording time is straightforward physics: tape speed times time equals tape length. Rearranged:
Recording seconds = (tape length in feet × 12) ÷ IPS speed
Multiply by the number of passes (flipping the reel) to get total content time. Track configuration — full, half, or quarter — does not change the physical recording time per pass. It affects audio quality (track width) and whether a "flip" is mechanically possible, not how long the tape runs.
Common Reel-to-Reel Tape Lengths
- 3" reel — SP (1.5 mil): ~150 ft; LP (1.0 mil): ~300 ft
- 5" reel — SP: ~600 ft; LP: ~900 ft; DP (0.5 mil): ~1,200 ft
- 7" reel — SP: ~1,200 ft; LP: ~1,800 ft; DP: ~2,400 ft
- 10.5" NAB reel — SP (1.5 mil): ~2,500 ft; LP (1.0 mil): ~3,600 ft; DP (0.5 mil): ~4,800 ft
These are nominal values. Actual footage varies by manufacturer; some makers pack ~5–6% extra tape. Double-play (0.5 mil) tape is fragile and prone to print-through — generally not recommended for critical recordings.
IPS Speed Reference
- 1⅞ IPS — slowest consumer speed; speech or ambient recordings where time matters more than fidelity
- 3¾ IPS — extended consumer use; voice journals, radio off-air recording
- 7½ IPS — the standard for hi-fi home taping and many pre-recorded commercial tapes
- 15 IPS — preferred by audiophiles and semi-pro studios; better high-frequency response and lower noise
- 30 IPS — professional mastering quality; uses tape quickly but captures the widest dynamic range
Track Configuration Explained
The term "tracks" refers to the number of parallel recording channels across the tape width. More tracks per tape width means each track is narrower, which reduces high-frequency fidelity and signal-to-noise ratio.
- Full-track mono — one track uses the entire tape width; maximum signal level, best S/N ratio
- Half-track (2-track) stereo — two channels side by side; by far the most common home and hi-fi format
- Quarter-track (4-track) stereo — two stereo pairs in opposite directions; flipping the reel plays/records the second stereo pair, doubling content per reel
- Quarter-track mono (4-track mono) — four separate mono tracks; used for multitrack home recording on consumer machines
Frequently Asked Questions
How do I calculate reel-to-reel tape recording time?
Divide the tape length in inches by the speed in inches per second. For example, 1,200 feet = 14,400 inches. At 7½ IPS, that's 14,400 ÷ 7.5 = 1,920 seconds, or 32 minutes per side. If you have a quarter-track deck and flip the reel, multiply by 2 for total content time. The formula is: Recording Seconds = (Feet × 12) ÷ IPS.
What does IPS mean on a reel-to-reel tape deck?
IPS stands for inches per second — the speed at which tape travels past the record and playback heads. The five common speeds are 1⅞, 3¾, 7½, 15, and 30 IPS. Higher speeds consume more tape but reproduce audio with better high-frequency response, lower noise, and less print-through. Lower speeds stretch recording time at the cost of fidelity.
How long does a 7-inch reel record at 7.5 IPS?
It depends on tape thickness: Standard-play (1.5 mil, ~1,200 ft) gives about 32 minutes. Long-play (1.0 mil, ~1,800 ft) gives about 48 minutes. Double-play (0.5 mil, ~2,400 ft) gives about 64 minutes — all for a single-sided pass with half-track stereo. Quarter-track decks with a reel flip can double those totals.
Does track configuration affect recording time?
Not the physical run time per pass — that's purely tape length ÷ speed, regardless of whether you're recording full-track, half-track, or quarter-track. Track configuration determines audio quality (track width), channel count, and whether a second pass by flipping the reel is practical. Quarter-track decks can flip for a second stereo pass, effectively doubling total content per reel.
What is the most common tape speed for home reel-to-reel recording?
7½ IPS is by far the most common for consumer and prosumer home recording. It offers a good balance between fidelity and tape economy. Serious audiophiles often choose 15 IPS for its wider frequency response and lower inherent noise — particularly valuable when recording vinyl or live performances.
Is thinner tape (Double Play / 0.5 mil) worth using?
Double-play tape fits twice as much footage on a reel, but the thinner base is prone to stretching, breakage, and — most critically — print-through (magnetic "bleed" from one layer to the adjacent one when the tape is stored wound). Most engineers avoid it for music. Long-play (1.0 mil) is generally the sweet spot between capacity and reliability for home use.
How much does reel-to-reel tape cost in 2025–2026?
New production tape (e.g., ATR Magnetics, RMG/RMGI, Mulann 468/911) currently runs roughly $30–$80 for a 7-inch reel and $60–$150+ for a 10.5-inch NAB reel, depending on the formulation and retailer. NOS (new old stock) vintage tape varies widely. Used or re-recorded tape can be found cheaply but carries condition risks. Always degauss and clean used tape before recording.