TPU hardness selector for 3D-printed insoles
Tell us how you'll use the insoles and get a starting firmness plus a top-cover suggestion. On a 3D print you set firmness two ways — the TPU durometer and the printed lattice density — so the same design can run plush or rigid. This is a design starting point, not medical advice.
1 · What will you mostly do in them?
2 · Comfort vs support preference
Your starting point
Pick an activity above ↑
Choose how you'll use the insoles and we'll suggest a firmness and top cover, with why.
Firmness here is a design starting point, not a medical recommendation. Body weight, foot shape and comfort all shift the right answer — print, wear, and re-export a firmer or softer version if it's not right. For foot pain or a diagnosed condition, see a podiatrist or clinician.
Firmness by activity — the reference
This tool is based on Ergono3D's own guidance. The pattern is simple: more load or force transfer → firmer; more comfort or impact cushioning → softer.
| Use case | Firmness | Starting durometer | Why |
|---|---|---|---|
| Everyday standing & walking | Softer | ~85A | Some support, but prioritise cushioning and comfort for casual standing and walking. |
| Run-and-jump sport | Medium | ~90A | Balance support, cushioning and rebound — firm enough to avoid the energy loss of a too-soft insole. |
| Hiking / backpacking (light load, long duration) | Medium–firm | ~90–95A | Moderate load but long time on feet, so support has to hold without packing out. |
| Heavy strength work (lifting) | Very firm | ~95A | Under maximal load you want a stable, near-zero-deformation base for force transfer. |
How firmness actually works on a 3D print
Firmness comes from both the TPU durometer and the printed internal structure. Because you control the lattice density as well as the filament, you can dial the same insole design from plush to rigid without changing its shape. A typical top cover is a soft EVA (around 25–40 Shore C, 2–3 mm) that adds comfort without compromising the shell's support; Poron adds durable cushioning that resists packing out, and leather suits dress shoes. Full detail in the TPU hardness & top-cover guide.
Source: Ergono3D — TPU hardness & top-cover guide and how to 3D print custom insoles.