• This formula can be used after a design system is established to calculate how much ROI a design system can bring to an organization over different time periods.

• The calculation timeline can be split into stages such as initial, mid-term, and mature stages, or year-by-year increments for rolling tracking—for instance, 1-year, 2-year, 3-year, and 5-year ROI. If you need to use a design system to reduce costs and increase efficiency for the company, or if you need to report the benefits of the design system to your superiors or other stakeholders, this formula may be needed.

• All calculation periods (M) in the formula should use the same monthly value

• In the early stage of the design system (requirements research, component setup), a large investment is needed, and the benefits are not yet fully visible. Especially in the first year, ROI is often quite low or even negative, which is normal.

• As the design system matures and the Scale Efficiency (SE) and Uniformity Value (UV) gradually increase, ROI becomes much more significant.

Design System ROI = [(TE + QE + SE + SCE) - (IC + MC)] / (IC + MC) × 100%

Meaning of the formula: Design System ROI = (Total benefits – Total costs) / (Total costs) × 100%

This is a way to measure what percentage return the “Design System” delivers given a certain level of investment.

TE = (Td × Rd × Dhd + Th × Rh × Dhh) × M

• Td (Time cost of Designer): Designer’s average hourly wage (USD/hour)• Rd (Rate of Design saving): Proportion of design time saved (e.g., 0.3)

• Dhd (Design working Hours): Monthly hours spent by designers on interface design

• Th (Time cost of Developer): Developer’s average hourly wage (USD/hour)

• Rh (Rate of Development saving): Proportion of development time saved (e.g., 0.4)

• Dhh (Development working Hours): Monthly hours spent by developers on interface development

• M (Months): Calculation period (months)

This item measures time savings (work hours × saving rates) for both designers and developers in UI design and development, converts those savings into direct manpower cost savings, and multiplies by the number of months (M).

QE = [(Bb - Ba) × Fp × Cd + (Ib - Ia) × Fp × Ci + UV] × M

• Bb (Bug density Baseline): Baseline bug density before a design system was used (bugs per function point, measured over a defined period)

• Ba (Bug density Actual): Actual bug density after the design system was implemented (same measurement period as Bb)

• Ib (Inconsistency Baseline): Number of inconsistencies before using the design system (inconsistencies per function point, measured over a defined period)

• Ia (Inconsistency Actual): Number of inconsistencies after implementing the design system (same measurement period as Ib)

• Fp (Function Points): Average monthly function points

• Cd (Cost per Debug): Average cost per bug fix (USD) (see 2.1)

• Ci (Cost per Inconsistency): Average cost per inconsistency fix (USD) (see 2.2)

• UV (Uniformity Value): Uniformity value (see 2.3)

• M (Months): Calculation period (months)

This measures cost savings from reduced bugs and inconsistencies, plus the comprehensive value that system uniformity (UV) brings.

Cd = Σ(Hd × Ch) / Nb

• Hd (Debug Hours): Total hours spent debugging and fixing bugs (defined period)

• Ch (Cost Hour): Average hourly wage (USD/hour)

• Nb (Number of Bugs fixed): Total number of bugs fixed in the same period

This formula calculates the “average cost to fix a single bug.” If the design system reduces bug density from Bb to Ba, that translates into (Bb - Ba) × Cd in repair cost savings.

Ci = [(Hd × Md) + (Hh × Mh)] / Ni

• Hd (Hours - designer): Total hours designers spend fixing interface inconsistencies (defined period)

• Md (Manhour cost - designer): Designer’s average hourly wage (USD/hour)

• Hh (Hours - developer): Total hours developers spend fixing inconsistencies (same period as Hd)

• Mh (Manhour cost - developer): Developer’s average hourly wage (USD/hour)

• Ni (Number of Inconsistencies): Total number of inconsistencies fixed in the period

First, calculate total cost by summing the hours designers and developers spend fixing inconsistencies and multiplying by their respective hourly rates; then divide by the total number of inconsistencies fixed in that period to get Ci.

UV = (RV + CV + QV) × BU

• RV (Rework Value): See 2.3.1

• CV (Communication Value): See 2.3.2

• QV (Quality Assurance Value): See 2.3.3

• BU (Brand Uniformity Coefficient): Recommended range 1.0 ~ 1.5

Uniformity Value captures benefits from “less rework, less communication overhead, less acceptance overhead.” If brand uniformity is critical, BU will amplify (or slightly adjust) the overall ROI.

RV = ((Rd × Td) + (Rh × Th)) × Rn_nonDefect × M

• Rd (Rework hours saved by Designer): Designer hours saved from rework (defined period)

• Td (Time cost of Designer): Designer’s hourly wage (USD/hour)

• Rh (Rework hours saved by Developer): Developer hours saved from rework (same period)

• Th (Time cost of Developer): Developer’s hourly wage (USD/hour)

• Rn_nonDefect (Rework Numbers - non-defect): Monthly rework requests not caused by bugs or inconsistencies

• M (Months): Calculation period (months)

To avoid double counting the bug/inconsistency fixes already covered in QE, only “non-defect” rework (caused by requirement changes, business strategy shifts, aesthetic changes, etc.) is counted here.

CV = [(Dm × Td) + (Hm × Th)] × Cm × M

• Dm (Designer meeting hours saved): Designer meeting hours saved (defined period)

• Td (Time cost of Designer): Designer’s hourly wage (USD/hour)

• Hm (Developer meeting hours saved): Developer meeting hours saved (same period)

• Th (Time cost of Developer): Developer’s hourly wage (USD/hour)

• Cm (Communication meetings reduced): Monthly reduction in communication meetings (same period)

• M (Months): Calculation period (months)

A standardized design language can reduce the need to repeatedly align on requirements or style, thus reducing meeting frequency and duration, saving costs.

QV = (Qd × Td × Pn) × M

• Qd (QA time saved per Design): Time saved in acceptance per page (hours)

• Td (Time cost of Designer): Designer’s hourly wage (USD/hour)

• Pn (Page Numbers): Monthly number of pages requiring acceptance

• M (Months): Calculation period (months)

A well-structured design system can reduce rework during design acceptance; “time saved per page × number of pages” estimates the total benefit.

SE = (Td_comp × Cdev) × Rr × Pn

• Td_comp (Time duration per Component): Development hours per component (hours)

• Cdev (Cost per Developer hour): Developer’s average hourly wage (USD/hour)

• Rr (Reuse Rate): Number of times components are reused (defined period)

• Pn (Project Numbers): Number of projects using the design system (same period)

When components are reused, you save the cost of building them from scratch. By multiplying the reuse rate (Rr) by the number of projects (Pn), you measure the overall reusable value.

SCE = (Sd × Rd × Sa × M) + (Hd × Rh × Sa × M)

• Sd (State design cost): Designer’s average hourly wage (USD/hour)

• Rd (Rate of state Design saving): Proportion of time saved for designing state pages (e.g., 0.5)

• Hd (State development cost): Developer’s average hourly wage (USD/hour)

• Rh (Rate of state development saving): Proportion of time saved for developing state pages (e.g., 0.6)

• Sa (State Amount saved): Number of state pages saved (pages × states)

• M (Months): Calculation period (months)

When pages or components have multiple states (hover, active, loading, etc.), a design system can provide standardized, consistent solutions that reduce repeated design and development work.

IC = Dc + Cc + Tc

• Dc (Design specification Cost): Cost of creating design specifications

• Cc (Core Component Cost): Cost of developing core components

• Tc (Technical document Cost): Cost of building technical documentation

Before using a design system, you incur the cost of creating design specifications, developing core components, and writing documentation. These together form the initial cost.

Dc = Dcd + Dct

Dcd (Design specification Cost for designers)= Dhdd × Cdd × Nd

• Dhdd (Design hours - designer): Hours each designer spends drafting the design specification (hours)

• Cdd (Cost per hour - designer): Designer’s hourly rate (USD/hour)

• Nd (Number of designers): Number of designers involved

Dct (Design specification Cost for developers)= Dhdt × Cdt × Nt

• Dhdt (Design hours - developer): Hours each developer spends assisting with the design specification (hours)

• Cdt (Cost per hour - developer): Developer’s hourly rate (USD/hour)

• Nt (Number of developers): Number of developers involved

Both designers and developers contribute effort to formalize the design language or specification, which adds up to the total cost of design specification creation.

Cc = Ccd + Cct

Ccd (Core Component Cost for designers)= Chdd × Cdd × Nd

• Chdd (Core hours - designer): Hours each designer spends defining UI/visual specs for core components (hours)

• Cdd (Cost per hour - designer): Designer’s hourly rate (USD/hour)

• Nd (Number of designers): Number of designers involved

Cct (Core Component Cost for developers)= Chdt × Cdt × Nt

• Chdt (Core hours - developer): Hours each developer spends coding and testing core components (hours)

• Cdt (Cost per hour - developer): Developer’s hourly rate (USD/hour)

• Nt (Number of developers): Number of developers involved

A design system needs reusable core components, which requires both design and development effort. This section covers the cost of that effort.

Tc = Tcd + Tct

Tcd (Technical document Cost for designers)= Thdd × Cdd × Nd

• Thdd (Tech doc hours - designer): Hours each designer spends creating/maintaining design guidance documents (hours)

• Cdd (Cost per hour - designer): Designer’s hourly rate (USD/hour)

• Nd (Number of designers): Number of designers involved

Tct (Technical document Cost for developers)= Thdt × Cdt × Nt

• Thdt (Tech doc hours - developer): Hours each developer spends writing/maintaining technical guides and example code (hours)

• Cdt (Cost per hour - developer): Developer’s hourly rate (USD/hour)

• Nt (Number of developers): Number of developers involved

Beyond specifications and components, you also need documentation to ensure the design system is easy to use and maintain.

MC = (Mrd + Rct) × M

Mrd (Maintenance & Response Cost Designer) = Mhd × Cmd × Nd

• Mhd (Maintenance hours designer): Monthly hours designers spend on maintenance/support (hours/month)

• Cmd (Cost designer maintenance): Designer’s hourly rate (USD/hour)

• Nd (Number of designers): Number of designers providing support

Rct (Response Cost Technical) = Rht × Crt × Nt

• Rht (Response hours technical): Monthly hours developers spend on support (hours/month)

• Crt (Cost developer response): Developer’s hourly rate (USD/hour)

• Nt (Number of technical): Number of developers providing support

• M (Months): Calculation period (months)

You do not need to calculate all these formulas manually; simply fill in the relevant numbers for each calculation item and ask an AI to compute them. Then you can request the ROI for Year 1, Year 2, Year 3, and so on.

• This formula can be used after a design system is established to calculate how much ROI a design system can bring to an organization over different time periods.

• The calculation timeline can be split into stages such as initial, mid-term, and mature stages, or year-by-year increments for rolling tracking—for instance, 1-year, 2-year, 3-year, and 5-year ROI. If you need to use a design system to reduce costs and increase efficiency for the company, or if you need to report the benefits of the design system to your superiors or other stakeholders, this formula may be needed.

• All calculation periods (M) in the formula should use the same monthly value

• In the early stage of the design system (requirements research, component setup), a large investment is needed, and the benefits are not yet fully visible. Especially in the first year, ROI is often quite low or even negative, which is normal.

• As the design system matures and the Scale Efficiency (SE) and Uniformity Value (UV) gradually increase, ROI becomes much more significant.

Design System ROI = [(TE + QE + SE + SCE) - (IC + MC)] / (IC + MC) × 100%

Meaning of the formula: Design System ROI = (Total benefits – Total costs) / (Total costs) × 100%

This is a way to measure what percentage return the “Design System” delivers given a certain level of investment.

TE = (Td × Rd × Dhd + Th × Rh × Dhh) × M

• Td (Time cost of Designer): Designer’s average hourly wage (USD/hour)• Rd (Rate of Design saving): Proportion of design time saved (e.g., 0.3)

• Dhd (Design working Hours): Monthly hours spent by designers on interface design

• Th (Time cost of Developer): Developer’s average hourly wage (USD/hour)

• Rh (Rate of Development saving): Proportion of development time saved (e.g., 0.4)

• Dhh (Development working Hours): Monthly hours spent by developers on interface development

• M (Months): Calculation period (months)

This item measures time savings (work hours × saving rates) for both designers and developers in UI design and development, converts those savings into direct manpower cost savings, and multiplies by the number of months (M).

QE = [(Bb - Ba) × Fp × Cd + (Ib - Ia) × Fp × Ci + UV] × M

• Bb (Bug density Baseline): Baseline bug density before a design system was used (bugs per function point, measured over a defined period)

• Ba (Bug density Actual): Actual bug density after the design system was implemented (same measurement period as Bb)

• Ib (Inconsistency Baseline): Number of inconsistencies before using the design system (inconsistencies per function point, measured over a defined period)

• Ia (Inconsistency Actual): Number of inconsistencies after implementing the design system (same measurement period as Ib)

• Fp (Function Points): Average monthly function points

• Cd (Cost per Debug): Average cost per bug fix (USD) (see 2.1)

• Ci (Cost per Inconsistency): Average cost per inconsistency fix (USD) (see 2.2)

• UV (Uniformity Value): Uniformity value (see 2.3)

• M (Months): Calculation period (months)

This measures cost savings from reduced bugs and inconsistencies, plus the comprehensive value that system uniformity (UV) brings.

Cd = Σ(Hd × Ch) / Nb

• Hd (Debug Hours): Total hours spent debugging and fixing bugs (defined period)

• Ch (Cost Hour): Average hourly wage (USD/hour)

• Nb (Number of Bugs fixed): Total number of bugs fixed in the same period

This formula calculates the “average cost to fix a single bug.” If the design system reduces bug density from Bb to Ba, that translates into (Bb - Ba) × Cd in repair cost savings.

Ci = [(Hd × Md) + (Hh × Mh)] / Ni

• Hd (Hours - designer): Total hours designers spend fixing interface inconsistencies (defined period)

• Md (Manhour cost - designer): Designer’s average hourly wage (USD/hour)

• Hh (Hours - developer): Total hours developers spend fixing inconsistencies (same period as Hd)

• Mh (Manhour cost - developer): Developer’s average hourly wage (USD/hour)

• Ni (Number of Inconsistencies): Total number of inconsistencies fixed in the period

First, calculate total cost by summing the hours designers and developers spend fixing inconsistencies and multiplying by their respective hourly rates; then divide by the total number of inconsistencies fixed in that period to get Ci.

UV = (RV + CV + QV) × BU

• RV (Rework Value): See 2.3.1

• CV (Communication Value): See 2.3.2

• QV (Quality Assurance Value): See 2.3.3

• BU (Brand Uniformity Coefficient): Recommended range 1.0 ~ 1.5

Uniformity Value captures benefits from “less rework, less communication overhead, less acceptance overhead.” If brand uniformity is critical, BU will amplify (or slightly adjust) the overall ROI.

RV = ((Rd × Td) + (Rh × Th)) × Rn_nonDefect × M

• Rd (Rework hours saved by Designer): Designer hours saved from rework (defined period)

• Td (Time cost of Designer): Designer’s hourly wage (USD/hour)

• Rh (Rework hours saved by Developer): Developer hours saved from rework (same period)

• Th (Time cost of Developer): Developer’s hourly wage (USD/hour)

• Rn_nonDefect (Rework Numbers - non-defect): Monthly rework requests not caused by bugs or inconsistencies

• M (Months): Calculation period (months)

To avoid double counting the bug/inconsistency fixes already covered in QE, only “non-defect” rework (caused by requirement changes, business strategy shifts, aesthetic changes, etc.) is counted here.

CV = [(Dm × Td) + (Hm × Th)] × Cm × M

• Dm (Designer meeting hours saved): Designer meeting hours saved (defined period)

• Td (Time cost of Designer): Designer’s hourly wage (USD/hour)

• Hm (Developer meeting hours saved): Developer meeting hours saved (same period)

• Th (Time cost of Developer): Developer’s hourly wage (USD/hour)

• Cm (Communication meetings reduced): Monthly reduction in communication meetings (same period)

• M (Months): Calculation period (months)

A standardized design language can reduce the need to repeatedly align on requirements or style, thus reducing meeting frequency and duration, saving costs.

QV = (Qd × Td × Pn) × M

• Qd (QA time saved per Design): Time saved in acceptance per page (hours)

• Td (Time cost of Designer): Designer’s hourly wage (USD/hour)

• Pn (Page Numbers): Monthly number of pages requiring acceptance

• M (Months): Calculation period (months)

A well-structured design system can reduce rework during design acceptance; “time saved per page × number of pages” estimates the total benefit.

SE = (Td_comp × Cdev) × Rr × Pn

• Td_comp (Time duration per Component): Development hours per component (hours)

• Cdev (Cost per Developer hour): Developer’s average hourly wage (USD/hour)

• Rr (Reuse Rate): Number of times components are reused (defined period)

• Pn (Project Numbers): Number of projects using the design system (same period)

When components are reused, you save the cost of building them from scratch. By multiplying the reuse rate (Rr) by the number of projects (Pn), you measure the overall reusable value.

SCE = (Sd × Rd × Sa × M) + (Hd × Rh × Sa × M)

• Sd (State design cost): Designer’s average hourly wage (USD/hour)

• Rd (Rate of state Design saving): Proportion of time saved for designing state pages (e.g., 0.5)

• Hd (State development cost): Developer’s average hourly wage (USD/hour)

• Rh (Rate of state development saving): Proportion of time saved for developing state pages (e.g., 0.6)

• Sa (State Amount saved): Number of state pages saved (pages × states)

• M (Months): Calculation period (months)

When pages or components have multiple states (hover, active, loading, etc.), a design system can provide standardized, consistent solutions that reduce repeated design and development work.

IC = Dc + Cc + Tc

• Dc (Design specification Cost): Cost of creating design specifications

• Cc (Core Component Cost): Cost of developing core components

• Tc (Technical document Cost): Cost of building technical documentation

Before using a design system, you incur the cost of creating design specifications, developing core components, and writing documentation. These together form the initial cost.

Dc = Dcd + Dct

Dcd (Design specification Cost for designers)= Dhdd × Cdd × Nd

• Dhdd (Design hours - designer): Hours each designer spends drafting the design specification (hours)

• Cdd (Cost per hour - designer): Designer’s hourly rate (USD/hour)

• Nd (Number of designers): Number of designers involved

Dct (Design specification Cost for developers)= Dhdt × Cdt × Nt

• Dhdt (Design hours - developer): Hours each developer spends assisting with the design specification (hours)

• Cdt (Cost per hour - developer): Developer’s hourly rate (USD/hour)

• Nt (Number of developers): Number of developers involved

Both designers and developers contribute effort to formalize the design language or specification, which adds up to the total cost of design specification creation.

Cc = Ccd + Cct

Ccd (Core Component Cost for designers)= Chdd × Cdd × Nd

• Chdd (Core hours - designer): Hours each designer spends defining UI/visual specs for core components (hours)

• Cdd (Cost per hour - designer): Designer’s hourly rate (USD/hour)

• Nd (Number of designers): Number of designers involved

Cct (Core Component Cost for developers)= Chdt × Cdt × Nt

• Chdt (Core hours - developer): Hours each developer spends coding and testing core components (hours)

• Cdt (Cost per hour - developer): Developer’s hourly rate (USD/hour)

• Nt (Number of developers): Number of developers involved

A design system needs reusable core components, which requires both design and development effort. This section covers the cost of that effort.

Tc = Tcd + Tct

Tcd (Technical document Cost for designers)= Thdd × Cdd × Nd

• Thdd (Tech doc hours - designer): Hours each designer spends creating/maintaining design guidance documents (hours)

• Cdd (Cost per hour - designer): Designer’s hourly rate (USD/hour)

• Nd (Number of designers): Number of designers involved

Tct (Technical document Cost for developers)= Thdt × Cdt × Nt

• Thdt (Tech doc hours - developer): Hours each developer spends writing/maintaining technical guides and example code (hours)

• Cdt (Cost per hour - developer): Developer’s hourly rate (USD/hour)

• Nt (Number of developers): Number of developers involved

Beyond specifications and components, you also need documentation to ensure the design system is easy to use and maintain.

MC = (Mrd + Rct) × M

Mrd (Maintenance & Response Cost Designer) = Mhd × Cmd × Nd

• Mhd (Maintenance hours designer): Monthly hours designers spend on maintenance/support (hours/month)

• Cmd (Cost designer maintenance): Designer’s hourly rate (USD/hour)

• Nd (Number of designers): Number of designers providing support

Rct (Response Cost Technical) = Rht × Crt × Nt

• Rht (Response hours technical): Monthly hours developers spend on support (hours/month)

• Crt (Cost developer response): Developer’s hourly rate (USD/hour)

• Nt (Number of technical): Number of developers providing support

• M (Months): Calculation period (months)

You do not need to calculate all these formulas manually; simply fill in the relevant numbers for each calculation item and ask an AI to compute them. Then you can request the ROI for Year 1, Year 2, Year 3, and so on.