> ## Documentation Index > Fetch the complete documentation index at: https://docs.charle.agency/llms.txt > Use this file to discover all available pages before exploring further. # Overview > How work estimation works in CharleOS Accurate estimation is the foundation of profitable delivery and predictable client costs. CharleOS uses a structured t-shirt sizing system combined with scoping best practices to estimate work consistently. ## Why Estimation Matters Good estimation enables: Accurate estimates create margin when delivery is efficient Realistic quotes build confidence and long-term relationships Precise estimates enable better scheduling and resource allocation Identifying complexity upfront prevents overruns ## The Estimation System CharleOS combines two complementary approaches: **Relative estimation using standardized time ranges** Instead of precise hours, work is sized using XS, S, M, L, XL, and XXL categories. Each size maps to a time range with a minimum, maximum, and average. **Benefits:** * Faster than precise hourly estimates * Accounts for uncertainty with ranges * Consistent across the team * Easy to explain to clients **Example:** * "Homepage update" → **M** (3-6 hours) * Simple, clear, and feeds into billing formula **Breaking work into estimable pieces** Before sizing, requirements are scoped to ensure clarity. Good scoping means: * Understanding what's included (and excluded) * Identifying dependencies and unknowns * Breaking large work into smaller pieces * Comparing to similar past work **Benefits:** * Reduces estimation errors * Clarifies expectations with clients * Makes work easier to schedule * Catches complexity early **Example:** * "Checkout flow" → Breaks into design, development, payment integration, testing * Each piece gets its own t-shirt size ## How It Works Together The estimation process follows a logical flow: Review the client's request or requirement description. Ask clarifying questions if anything is ambiguous. Understand the desired outcome. Define what's included: * What deliverables are expected? * What's explicitly excluded? * Are there design and development components? * What dependencies exist? Break large requirements into smaller, estimable pieces. For each scoped piece, select the appropriate t-shirt size: * Consider complexity, unknowns, and dependencies * Reference similar past work * Choose the size that fits the range Remember: Each size includes core work PLUS QA/feedback buffer. Review the total estimate: * Does it feel reasonable compared to similar work? * Have you accounted for risks and complexity? * Is the scope clear enough to justify the estimate? Adjust if needed before finalizing. ## Estimation in CharleOS ### Where Estimates are Used When creating quotes, each requirement block is assigned a t-shirt size. The quote shows the time range to the client (e.g., "M: 3-6 hours") and calculates the total estimated time. Requirements can have both **design** and **development** sizes for work with multiple components. When quotes are converted to tasks, the t-shirt sizes carry over. Tasks inherit the estimate, which becomes the billing cap. Task-level estimates feed into: * Scheduling and capacity planning * Billing calculations (MIN/MAX formula) * Efficiency tracking (actual vs estimate) Estimates are used to allocate capacity to the schedule. The system calculates how much time is needed and distributes it across available days. The 80/20 split (core work vs QA/feedback) helps allocate work to the right team members. ## Common Estimation Scenarios ### Scenario 1: Simple, Well-Defined Work **Example:** "Update footer copyright year and add privacy link" **Approach:** * Work is clear and specific * No unknowns or dependencies * Quick change with minimal testing * **Size:** XS (0-30 minutes) ### Scenario 2: Moderate Complexity **Example:** "Add product filtering by category on shop page" **Approach:** * Requires backend query changes and frontend UI * Existing patterns to follow * Standard testing required * **Size:** M (3-6 hours) ### Scenario 3: High Complexity **Example:** "Build custom booking system with availability calendar" **Approach:** * Multiple components (calendar, booking form, admin) * Complex logic (availability, conflicts, notifications) * Extensive testing needed * **Break it down:** * Calendar UI: L (8-16 hours) * Booking logic: XL (24-40 hours) * Admin panel: M (3-6 hours) * Testing & polish: L (8-16 hours) * **Total:** 43-75 hours across multiple sizes XXL sizes (40-120 hours) should be rare. If a requirement is XXL, consider breaking it into smaller deliverables to reduce risk and improve scheduling. ### Scenario 4: Unknown or Discovery Work **Example:** "Investigate API integration options for \[third-party service]" **Approach:** * Treat discovery as its own task * Size the discovery phase separately (usually S or M) * Estimate the implementation after discovery is complete * **Discovery:** S (1-2 hours) * **Implementation:** TBD (after discovery) ## Estimation Best Practices If you're torn between two sizes, choose the larger one. It's better to deliver faster than expected (creating banked time) than to consistently overrun. Example: Feels like a large S or small M? → Choose M. Smaller estimates are more accurate than large ones. Instead of one XL task, consider three M tasks. This also improves scheduling flexibility. Rule of thumb: If it's XXL, try to split it. Look at similar completed tasks: * How long did they actually take? * What was the estimated vs actual? * What unexpected issues arose? Use history to calibrate your estimates. Factors that increase complexity: * Working with unfamiliar tech * Client's codebase is messy or undocumented * Multiple dependencies or stakeholders * High-risk changes (payment, auth, etc.) Add buffer by sizing up when these factors are present. T-shirt sizes include core work AND QA/feedback time. Don't just estimate the happy path—account for: * Internal QA finding bugs * Client feedback requiring revisions * Multiple fix/review rounds The 20% buffer is built in, but complex work may need a larger size. ## How Estimates Feed Billing Estimates directly impact billing through the value-based formula: ```formula theme={null} Billable = MIN(maximum, MAX(average, actual)) ``` **Example: M size (3-6 hours, average 4.5 hours)** **Actual:** 3 hours\ **Billable:** 4.5 hours (average)\ **Result:** 1.5 hrs banked (profit) **Actual:** 5 hours\ **Billable:** 5 hours (actual)\ **Result:** No margin, but fair **Actual:** 7 hours\ **Billable:** 6 hours (maximum)\ **Result:** 1 hr overage (absorbed) **Why this matters:** * **Underestimating** consistently creates chronic overruns, hurting profitability * **Overestimating** creates unrealistic client expectations and may lose deals * **Accurate estimation** balances risk and opportunity ## Tools and Resources Complete reference on size ranges, how to choose, and what's included Best practices for breaking down and defining work before estimating How estimates feed into the value-based billing formula Step-by-step guide to applying estimates in quotes