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Compliance/Effective Mass Calculator
Dozens of compliance calculators exist on the web. They all use the same ancient formula that is not supported by the measurements. They all give you the same useless one-number result.

Ours is different. Instead of giving you one number, we will plot acceleration and displacement charts based on your data. If the charts are mostly in the green zone, you're good. There is a more detailed interpretation guide below the charts.
Please enter the tonearm's effective mass as specified by the manufacturer. If it is given without a cartridge and headshell, please enter their respective masses too. For a tonearm without a removeable headshell, leave the last field empty unless you use particularly heavy mounting hardware.
The "Compliance" field is for the cartridge compliance. Please note that for some Japanese cartridges, the dynamic compliance given at 100 Hz is a completely different measure, given to estimate the tracking at specified downforce.

After you press "Calculate", the charts below the entry form would be updated based on your data.
How to Interpret the Results
Acceleration: your line should be in the green zone.
If it isn't, expect attenuated low frequencies as more energy is transmitted into the tonearm and less is converted into the electrical signal. Tracking might also suffer as the tonearm has to work a lot harder.

Empirically, it doesn't seem to matter much whether the chart for your combination is at the bottom or at the top of the green zone. Stay below 0.05g, and you'll be fine.
Excursion: aim for smaller overshoot
The amplitude of stylus movement is given as 0.1mm. Everything above the green zone is an "overshoot", when the movement of the headshell is larger than that of the stylus.

It's inevitable in an elastic system. Empirically, the overshoot that's spread over a wide frequency range is worse than the one that's more concentrated. But having a short sharp overshoot below 5 Hz might not work very well with some high compliance cartridges—they might reach their cantilever travel limits.

Examples
35 gram effective mass, 15 μm/mN compliance. We're all good, this is a combination that works really well. A small overshoot at about 5 Hz should be harmless.
14 gram effective mass, 5 μm/mN compliance. Say, a DL-103 on a light arm. Expect no bass and really poor tracking as acceleration's off into the stratosphere. The excursion overshoot is spread from 5 to 15 Hz.
40 gram effective mass, 40 μm/mN compliance. For example, a Grado F3+ on a vintage Micro-Trak arm. Short sharp excursion overshoot at 2-3 Hz. The stylus might hit the hard stops on warped/excentric LPs.