Turntable calculators for stylus hours, tonearm nulls, and platter cents.
These benches use the same constants as the StrobeHz studio on iPhone: 21 minutes per LP side, IEC 60098 groove radii at 60.325 mm and 146.05 mm, and musical cents as 1200 times log2 of actual over target. The arithmetic stays in the browser. Nothing is sent to a server, and there is no account.
33 1/3, 45, and 78.26 RPM, in percent and in cents.
A belt that runs 0.8 percent fast is about 14 cents sharp. The strobe guide turns a measured RPM into signed speed error, pitch in cents, and peak-to-peak wow and flutter when you have a slow reading and a fast reading.
Diamond hours for ten reference cartridges.
Enter LP sides or full albums. Each side counts as 21 minutes. The ceiling follows the diamond profile in the StrobeHz catalog: bonded elliptical 300 h, conical 400 h, nude elliptical 500 h, MicroLine 800 h.
| Cartridge | Diamond | Rated life |
|---|---|---|
| Ortofon 2M Red | Bonded Elliptical | 300 h |
| Ortofon 2M Blue | Nude Elliptical | 500 h |
| Ortofon 2M Bronze | MicroLine | 800 h |
| Audio-Technica AT-VM95E | Bonded Elliptical | 300 h |
| Audio-Technica AT-VM95ML | MicroLine | 800 h |
| Nagaoka MP-110 | Bonded Elliptical | 300 h |
| Nagaoka MP-200 | Nude Elliptical | 500 h |
| Sumiko Rainier | Bonded Elliptical | 300 h |
| Denon DL-103R | Conical | 400 h |
| Rega Nd5 | Nude Elliptical | 500 h |
| Arm | Pivot to spindle | Where the distance comes from |
|---|---|---|
| Technics SL-1200 | 215 mm | 215 mm, from 230 mm effective length minus 15 mm overhang |
| Rega Planar | 222 mm | 222 mm mounting distance, published for RB220, RB330, and RB880 |
| Pro-Ject Debut | 200 mm | 200 mm pivot-to-spindle, published for the 8.6 inch Debut arm |
Overhang, offset, and null radii for three tonearm families.
Pivot-to-spindle distances come from Technics, Rega, and Pro-Ject documentation, cited on each page. The table then solves Baerwald, Lofgren B, and Stevenson. Null radii are fixed by the IEC groove. Overhang and offset change with the arm.
Questions about these calculators
Do these pages measure my turntable?
No. The iPhone app reads the gyroscope. These pages compute from numbers you type: sides played, a pivot-to-spindle distance, or an RPM you already measured with a strobe disc, a test record, or the app.
Why do the factory overhang figures differ from the Baerwald column?
Technics, Rega, and Pro-Ject publish their own factory alignment. Baerwald, Lofgren B, and Stevenson are separate geometry targets on the same mounting distance. Each tonearm page shows the factory figures and the three curves, and it does not relabel the factory number as Baerwald.
The iPhone studio measures the platter you cannot type in.
StrobeHz on iPhone and iPad reads Z-axis rotation, logs stylus sides beside the listening chair, and prints a 1:1 arc protractor. These browser benches stay free of accounts. The app, including its passes, is described on the home page.