The right running shoe should feel secure without restricting the natural movement of your foot. Because every KARHU running model has its own shape, cushioning and intended use, sizing can vary slightly between models.
Use this guide to compare the fit, width and sizing recommendations of the current KARHU running shoe collection, including the Fusion 5.0, Ikoni 3.5, Ikoni ATR, Ikoni Trail and Mestari Run 2.0.
Our most accurate sizing advice: measure the length of both feet in millimetres while standing, then compare the longer measurement with the KARHU size chart. If you are between sizes, the larger size is often the better choice for longer runs.
The table below provides a quick comparison. Always check the product page before ordering, as recommendations can differ between standard and weather-resistant versions.
| Model | Fit profile | Size advice | Width options | Best suited for |
|---|---|---|---|---|
| Fusion 5.0 | Secure through the midfoot with additional room in the toe box. | Order 0.5 size up | Regular Men's HiVo 2E Women's HiVo D | Responsive everyday road running and faster daily training. |
| Ikoni 3.5 | Balanced and supportive with an adaptable knitted upper. | Order 0.5 size up | Regular Men's HiVo 2E Women's HiVo D | Everyday running, neutral runners and mild overpronation. |
| Ikoni ATR | Balanced and supportive road-to-trail fit. | True to size Weather-resistant versions: order 0.5 size up. | Regular | Mixed surfaces, gravel paths and light trails. |
| Ikoni Trail | Secure trail fit with more forefoot volume for natural toe movement. | True to size Consider 0.5 size up when wearing thicker socks. | Regular | Trail running, uneven terrain and longer off-road runs. |
| Mestari Run 2.0 | Plush, secure and supportive with a max-cushioned feel. | True to size | Regular Men's HiVo 2E Women's HiVo D | Long runs, recovery runs and comfortable high-mileage training. |
Selected KARHU running models are offered in both Regular and HiVo fits. Choosing the correct width can provide more comfort than simply selecting a longer shoe.
The Regular fit is designed for runners with an average-width foot. It should hold the heel and midfoot securely while allowing the toes enough room to move naturally.
HiVo versions provide additional room across the shoe. Men's HiVo models use a 2E width, while women's HiVo models use a D width. HiVo changes the width and internal volume, not the length of the shoe.
If the length feels correct but the sides of the shoe feel tight, consider a HiVo version instead of automatically choosing a longer size.
The Fusion 5.0 combines a secure midfoot feel with more room around the toes. Its fit supports a responsive and propulsive ride while allowing the forefoot to move naturally during toe-off.
The Ikoni 3.5 offers a balanced and supportive fit for everyday training. Its adaptable upper and wider underfoot platform help create a comfortable, guided feel for neutral runners and runners with mild overpronation.
The Ikoni ATR is designed to move comfortably between pavement, gravel and light trails. It provides a balanced and supportive fit for runners who want one shoe for varied surfaces.
The Ikoni Trail provides a secure trail-running fit with slightly more volume in the forefoot. This gives the toes space to spread and can improve comfort during longer runs on uneven terrain.
The Mestari Run 2.0 delivers a plush and secure fit with maximum cushioning and additional stability. It is designed for runners seeking comfort during long runs, recovery sessions and high-mileage training.
Your toes should be able to move naturally without touching the front of the shoe. Remember that feet can swell during longer runs.
The heel should remain comfortably in place while running. A small amount of movement can be normal, but excessive slipping may cause irritation.
The shoe should hold the middle of your foot securely without pressure, pinching or numbness.
If a shoe feels tight at the sides but has sufficient length, a wider HiVo fit may be more suitable than moving up another size.
Start with your foot measurement, compare the fit profiles and choose the KARHU running shoe that matches your preferred cushioning, terrain and training style.
