Repair Café Waste Diversion Impact Calculator
This Repair Café Waste Diversion Impact Calculator helps you estimate how much waste your events keep out of landfill, how much embodied carbon you avoid, and how many volunteer hours and specialist follow-ups you are likely to need. It is designed for repair café organizers, circular economy nonprofits, and municipal waste teams who want quick, order-of-magnitude impact numbers for planning and reporting.
How this repair café impact calculator works
The tool takes your typical repair café cadence (events per month), item flow (items brought and successfully repaired), and staffing pattern (volunteers and shift length). It then scales those monthly inputs to show approximate annual diversion, carbon savings, and labor needs.
At a high level, the calculator follows these steps:
- Estimate items successfully repaired per event.
- Convert successful repairs into diverted weight and avoided embodied carbon.
- Scale results from per event to monthly and annual totals.
- Estimate volunteer hours available and typical diagnosis capacity.
- Approximate how many items will require specialist follow-up.
Key formulas
Let:
- E = repair café events per month
- I = average items brought per event
- R = successful repair rate (percent)
- W = average weight per item (kg)
- C = embodied carbon per item (kg CO₂e)
- V = volunteers per event
- H = volunteer shift length (hours)
- D = average diagnosis time per item (minutes)
- T = percentage of items needing specialist follow-up (percent)
A core calculation is the number of items successfully repaired per event:
From this, the calculator derives monthly and annual landfill diversion (by weight) and carbon savings:
-
Items repaired per month =
Items_repaired,event × E -
Items repaired per year =
Items_repaired,event × E × 12 -
Landfill diversion per month (kg) =
Items_repaired,event × E × W -
Landfill diversion per year (kg) =
Items_repaired,event × E × W × 12 -
Carbon savings per month (kg CO₂e) =
Items_repaired,event × E × C -
Carbon savings per year (kg CO₂e) =
Items_repaired,event × E × C × 12
Volunteer hours and triage capacity are based on simple time estimates:
- Volunteer hours per event =
V × H - Volunteer hours per month =
V × H × E - Diagnosis capacity per event (items) ≈
(V × H × 60) ÷ D - Items needing specialist follow-up per event =
I × (T ÷ 100)
Understanding landfill diversion and embodied carbon
Landfill diversion in this context means the total weight of items you keep in use through repair rather than sending to disposal. It is a proxy for avoided waste and can be reported in kilograms or tonnes per year.
Embodied carbon (kg CO₂e) is the greenhouse gas impact associated with producing and distributing an item, expressed as kilograms of carbon dioxide equivalent. When you extend the life of a product, you delay or avoid the need for a replacement, which effectively “saves” part of that embodied carbon. This calculator uses your input for embodied carbon per item and scales it by the number of successful repairs.
How to interpret your results
The output panels typically show:
- Monthly and annual diverted weight – useful for waste reports and circular economy dashboards.
- Monthly and annual carbon savings – indicative climate impact, often used in funding or CSR reporting.
- Total volunteer hours – helps with scheduling, volunteer recruitment, and recognizing contributions.
- Diagnosis capacity – checks whether your volunteers can realistically assess all incoming items.
- Specialist follow-ups – a rough count of items that may need external repair partners or follow-up clinics.
In broad terms, for a neighborhood-scale repair café:
- Diverting a few hundred kilograms per year is a solid start and shows that your events are working.
- Crossing 1,000–2,000 kg/year suggests a mature, well-attended program with strong community engagement.
- Above 5,000 kg/year often indicates a larger city-wide network or frequent events with high throughput.
Worked example
Suppose a community group runs:
- 3 repair café events per month (E = 3)
- 48 items brought per event (I = 48)
- 62% successful repair rate (R = 62)
- Average weight 3.2 kg per item (W = 3.2)
- Embodied carbon 45 kg CO₂e per item (C = 45)
- 22 volunteers per event, 4-hour shifts (V = 22, H = 4)
- Average diagnosis time 18 minutes per item (D = 18)
- 22% of items need specialist follow-up (T = 22)
Items successfully repaired per event:
Items_repaired,event = 48 × (62 ÷ 100) ≈ 29.8 ≈ 30 items
Diversion and carbon savings per year:
-
Items repaired per year ≈
30 × 3 × 12 = 1,080 items -
Landfill diversion per year ≈
30 × 3 × 3.2 × 12 ≈ 3,456 kg(about 3.5 tonnes) -
Carbon savings per year ≈
30 × 3 × 45 × 12 = 48,600 kg CO₂e(about 48.6 tonnes CO₂e)
Volunteer effort and capacity:
-
Volunteer hours per event =
22 × 4 = 88 hours -
Volunteer hours per month =
88 × 3 = 264 hours -
Theoretical diagnosis capacity per event ≈
(22 × 4 × 60) ÷ 18 ≈ 293 items, comfortably above the 48 items expected.
Items needing specialist follow-up per event:
Specialist items,event = 48 × (22 ÷ 100) ≈ 10.6 ≈ 11 items
Over a year, this is around 11 × 3 × 12 ≈ 396 items where you may want partnerships with specialist repairers or follow-up sessions.
Example scenarios and typical ranges
The table below compares three stylized scenarios to give you a feel for scale. These are not presets in the calculator, just illustrative benchmarks.
| Scenario | Events / month | Items / event | Repair rate | Approx. annual diversion |
|---|---|---|---|---|
| Minimal pilot café | 1 | 20 | 50% | ~230 kg/year (assuming 2.0 kg/item) |
| Typical community program | 3 | 40–60 | 55–65% | ~2–4 tonnes/year (3–4 kg/item) |
| Ambitious city network | 6+ | 75–100 | 60–75% | 5+ tonnes/year (varied item mix) |
Use this table as a sense check. If your inputs suggest much higher or lower diversion than expected for your scale, revisit your assumptions around item weights, repair success rate, or embodied carbon per item.
Assumptions, limitations, and data sources
This calculator is intentionally simple and makes several assumptions:
- Average item weight and carbon – You provide a single average weight and embodied carbon value per item. In reality, a mix of textiles, electronics, and furniture will have very different profiles. If you have better category-level data, adjust your averages accordingly.
- Repair success is independent per item – The model assumes each item has the same probability of being successfully repaired, which may not hold if you specialize in a few repair types.
- Linear scaling over 12 months – Monthly activity is simply multiplied by 12 to produce annual figures. Seasonal variations, special events, or one-off campaigns are not explicitly modeled.
- Embodied carbon attribution – The tool treats each successful repair as if it “saves” the full embodied carbon of a replacement item. In practice, life cycle assessments often allocate only a portion of embodied carbon to life extension, depending on how much additional life you add.
- Diagnosis time and capacity – The diagnosis capacity is a rough theoretical upper bound and does not account for breaks, complex jobs, or time spent on education and conversation.
For embodied carbon and typical weights, many programs draw on published life cycle assessment (LCA) databases, academic studies, or manufacturer environmental product declarations. If your municipality or organization has its own factors for common product categories, you can substitute those values for more accurate reporting.
Using this tool alongside other resources
This calculator is best used as a planning and communication aid rather than a formal inventory. For detailed greenhouse gas accounting, you may also want to reference broader carbon footprint or waste diversion tools, and, where available, local guidance on reporting reuse and repair outcomes.
Pairing these quick estimates with qualitative stories from volunteers and participants can help make a stronger case to funders, policymakers, and community stakeholders for sustaining and scaling your repair café work.
Why Repair Cafés Need Their Own Impact Calculator
Repair cafés transform the throwaway economy by teaching neighbors to mend electronics, appliances, textiles, and furniture that might otherwise head to the landfill. Yet many repair crews struggle to quantify their impact when approaching funders, policymakers, or local climate offices. Spreadsheets often focus on monetary donations rather than the hours of skilled labor, the volume of materials diverted, or the greenhouse gas emissions avoided when a toaster is revived instead of replaced. This calculator highlights those hidden numbers. It gives volunteer coordinators a way to translate event logistics into annualized waste diversion metrics, carbon savings, and staffing commitments so they can celebrate victories, make the case for grants, and plan for growth.
The inputs mirror the questions coordinators typically ask after each event: how many repair parties happen per month, how many items come through the door, the share that leave working, the average weight and embodied carbon of each item, the number of volunteers and their shift lengths, how long diagnostics take, and how big the parts budget needs to be. The tool also tracks what percentage of items require specialist follow-up, such as sewing machine timing or smartphone micro-soldering. By submitting the form, you trigger JavaScript that validates each entry, converts units, and calculates total material diverted, carbon emissions avoided, volunteer hours, and triage case load. The results show both monthly and annual estimates so you can communicate the magnitude of community care.
How Diversion and Labor Are Calculated
Landfill diversion hinges on three core variables: the number of items brought in, the average weight per item, and the success rate. Multiply those together and you get the kilograms diverted per event. To annualize, the calculator multiplies by events per month and then by twelve. Carbon savings use a similar approach but leverage the embodied carbon of each item. When an item is repaired rather than replaced, you prevent emissions associated with manufacturing and distribution. The MathML below shows the annual diversion formula:
where is annual kilograms diverted, is events per month, is items per event, is weight per item, and is the repair success rate as a decimal. Volunteer hours per month are calculated by multiplying volunteers per event by shift length and events per month. Diagnosis time per item is converted to total volunteer minutes needed and compared against available volunteer hours to flag whether the crew is at risk of burnout. The parts budget simply multiplies by events per month, giving coordinators clarity on the fundraising targets they must hit.
Worked Example: Library-Based Repair Crew
Picture a repair café hosted at a public library. Volunteers run three events per month. Each event welcomes about forty-eight items ranging from blenders to denim jackets. The crew boasts a 62 percent repair success rate. The average item weighs 3.2 kilograms and carries 45 kilograms of embodied carbon. Twenty-two volunteers show up per event, each offering a four-hour shift. Diagnosing each item takes eighteen minutes on average. The parts table usually needs $260 per event, and twenty-two percent of items are referred to specialists for follow-up.
Entering those numbers, the calculator reports 95.5 kilograms diverted per event (48 items × 3.2 kg × 0.62). Over a month, that becomes 286.5 kilograms, and over a year it hits 3,438 kilograms. Carbon savings add up to 1,337.6 kg CO₂e per event and 16,051 kg CO₂e annually. Volunteer hours total 264 per month (22 volunteers × 4 hours × 3 events). The diagnostic workload is 2,592 minutes per month (48 items × 18 minutes × 3 events), equivalent to 43.2 hours. Because the available volunteer hours far exceed the diagnostic load, the result encourages rotating in apprentices or partnering with youth programs to build skills. The parts budget target is $780 per month. With twenty-two percent of items needing specialist follow-up, the team plans for roughly 32 items per month requiring additional coordination.
Scenario Comparison Table
Use the following table to compare different investment levels and their impact on diversion metrics. These scenarios help demonstrate the value of growing volunteer ranks or raising parts funding.
| Scenario | Events / Month | Annual Diversion | Annual Carbon Savings | Volunteer Hours / Month | Notes |
|---|---|---|---|---|---|
| Current Operations | 3 | 3,438 kg | 16,051 kg CO₂e | 264 | Healthy volunteer buffer |
| Monthly Expansion | 4 | 4,584 kg | 21,402 kg CO₂e | 352 | Requires extra parts funding |
| Quarterly Mega Fair | 5 | 5,730 kg | 26,752 kg CO₂e | 440 | Watch volunteer burnout |
Triage Capacity Table
Coordinators often wonder how many specialists they need on call. The table below translates the specialist follow-up percentage into monthly caseloads at different item volumes.
| Items per Event | Specialist Rate | Items Needing Follow-Up / Month | Recommended Specialists |
|---|---|---|---|
| 40 | 22% | 26 | 4 rotating specialists |
| 60 | 22% | 40 | 6 rotating specialists |
| 80 | 22% | 53 | 8 rotating specialists |
Limitations and Assumptions
The calculator assumes every repaired item would have been landfilled otherwise, which may overstate diversion if some participants would have pursued commercial repair. It also treats the embodied carbon figure as a fixed number per item, even though electronics, textiles, and furniture vary widely. For a conservative estimate, choose lower carbon numbers or run multiple scenarios. Volunteer hours are assumed to be entirely available for diagnostics and repairs, but in practice coordinators must budget time for intake, food, documentation, and safety protocols. The model does not account for the educational value of teaching participants how to repair their own items, nor does it quantify the emissions savings from deferred purchases down the line.
The success rate is treated as static even though it tends to improve as crews gain experience and build spare parts libraries. Weather, supply chain delays for replacement components, and volunteer skill mix can all swing success rates from one month to the next. The calculator also assumes that specialist follow-up is handled outside the main event. If your repair café schedules separate clinics for complex items, you may want to add those to the events per month input for a more accurate workload picture. Finally, the model does not monetize the social value of connecting neighbors or reducing loneliness, though those qualitative benefits often drive continued participation.
Related Planning Tools
Repair cafés frequently collaborate with other community infrastructure. When events run late or require portable power, organizers can reference the tool library maintenance rotation planner to ensure shared equipment stays in top shape. To evaluate the climate resilience of the venues hosting the café, pair this tool with the community mesh network uptime and backhaul planner, which helps keep registration and ticketing systems online during outages. Linking these calculators paints a full picture of circular economy readiness.
By quantifying impact, repair cafés can inspire policy changes such as right-to-repair legislation, municipal grants for reuse centers, and school partnerships that teach repair skills. Use the outputs to craft annual impact reports, apply for funding, and recruit volunteers by showing how their labor translates into tangible environmental wins. Numbers are not the only story, but they help allies understand the scale of commitment required to keep the fix-it culture thriving. Keep revisiting the calculator as your café grows, and share the link with other organizers building a global network of repair justice.