With Grundheim's SIA 102 fee calculator you estimate the architect's fee for a new build or conversion in Switzerland in a few minutes. Enter the fee-determining construction costs, the building category under SIA 102 (factor n from 0.7 to 1.3), the sub-phases 31 to 53 you want and an hourly rate. The calculator shows the fee net and with 8.1 % VAT, the share of construction costs, the split across preliminary project, building project, permit, tender, execution planning, site management and completion, plus a guide-value band. In "Check offer" mode you compare a fee offer you received with the guide value. Important: since the 2020 edition the SIA publishes neither a fee formula nor tariffs; every figure is a guide value for negotiation, not a tariff.
SIA 102 is the "Regulation for Services and Fees of Architects". It describes the basic services per sub-phase (31 preliminary project, 32 building project, 33 permit procedure, 41 tender, 51 execution planning, 52 execution, 53 commissioning and completion) and knows three fee models: by time, by fee-determining construction costs and as a lump sum. The former formula with the coefficients Z1 and Z2 (art. 7) has not been published since 2020 after an intervention of the Competition Commission. The calculator uses it only in expert mode with the last published values from 2015.
In "Guide value" mode a fee rate in percent of the fee-determining construction costs is derived: it falls as construction costs rise (around 15 % at CHF 800,000, around 12 % at CHF 5 million) and is multiplied by the factor n of the building category, the conversion factor and the share of the selected sub-phases. In "Time" mode the calculator derives the hours with the SIA logic (B × p/100 × n × q/100 × r × U with p = Z1 + Z2/∛B) and multiplies them by your hourly rate. In "Check offer" mode it relates an offer you received to the guide value: below 80 % low, 80 to 120 % within the band, up to 140 % high, above that clearly above.
SIA 102 (2014 edition, art. 7.6) distinguishes seven building categories with a factor n from 0.7 (very simple requirements) to 1.3 (highest requirements); category IV with n = 1.0 is the reference. The allocation list in art. 7.6.5 has not been published since the 2018 calculation aid; it listed condominiums, single-family houses and holiday homes in three tiers (average, with individual requirements, with the highest requirements). In practice a single-family house is usually costed with n = 1.0 to 1.2. Each tier changes the fee by around 10 %, so the factor is the most important point of negotiation.
The KBOB recommendation 2026 no longer states amounts in francs, only the qualification categories A to G. The maximum rates some cantons publish for direct awards serve as a guide: Zug and Schwyz (as of 2024) range from CHF 104 (category G, auxiliary staff) to CHF 251 (category A, management of large projects) per hour, excluding VAT. Private offers for single-family houses usually sit between CHF 120 and CHF 180 per hour as a blended rate.