# How to Read a Position-Size Calculation Read a position-size calculation through its budget, distance, and unit value. Keep the arithmetic separate from an order instruction or an actual loss. By OPT Team | Published 2026-11-05 | Updated 2026-11-05 [Read the canonical HTML article](https://www.onepurposetrading.com/blog/how-to-read-a-position-size-calculation) ## What does the calculation describe? ## Summary A position-size calculation connects a stated budget with a stated amount per unit. Read it as arithmetic with explicit assumptions, keeping the quotient separate from an order instruction. CME's position-size example multiplies a tick distance by the value of a tick to calculate a per-contract amount. [CME Group](https://www.cmegroup.com/education/courses/trade-and-risk-management/proper-position-size) Preserve the units at each step before interpreting the final number. Start with a calculation card, not an order ticket. Name the budget, the chosen distance, and the value assigned to one distance unit. Keep the source of every input beside its value. The exercise on this page uses fictional numbers to follow multiplication and division. It does not select a contract, choose a stopping price, or prescribe a quantity for a real account. A completed equation can still leave practical questions unanswered. Keep those questions visible instead of treating the arithmetic as a complete decision. ## Which inputs belong in the record? ## Summary Keep the budget, distance, and unit value in separate fields, with their units written out. Record whether each number is supplied for an example or copied from a dated source. A calculation should be traceable without guessing whether a distance is measured in ticks, points, or another unit. Use one row for the budget and another for the per-unit amount. Under the second row, show the multiplication that produces it. Write the quotient only after those inputs have been labeled. For a real document review, preserve the source title, relevant contract identity, and the time at which a value was recorded. If a specification or account figure is missing, leave that field unresolved. Do not copy a number from a similarly named product into a blank field. Keep the identity question with the record until the relevant source has been checked. This is a reading procedure for a calculation. The record should distinguish source values, chosen assumptions, and derived numbers. ## How do you read a fictional example? ## Summary Use a fictional budget of `100` currency units, distance of `5` ticks, and value of `2` currency units per tick per unit. Multiplying distance by tick value gives `10` currency units per unit. Dividing the supplied budget by that amount gives a quotient of `10` units. Write the first line as `5 ticks x 2 currency units per tick = 10 currency units` for one unit of the fictional position. Write the second line as `100 / 10 = 10`. Label the result “arithmetic quotient under the supplied assumptions.” It is not a direction to place an order. Keep the budget of one hundred separate from the quotient of ten. The first is a currency amount; the second is a count. Their units explain why the division has the shape it does. This example is illustrative only and does not indicate typical results. No actual contract, account, execution price, commission schedule, or subsequent outcome is supplied. Retain those omissions beside the equation rather than filling them with familiar-looking values. ## What remains outside the arithmetic? ## Summary The arithmetic does not establish an actual loss amount. A stop-loss or stop-limit order does not necessarily limit a loss to its intended amount, because market conditions can prevent execution. [National Futures Association](https://www.nfa.futures.org/members/member-resources/files/cta-disclosure-documents.pdf) Keep the chosen calculation inputs separate from execution conditions and any later account record. A budget written on a planning card is not a record of what ultimately happened. List the items the example leaves unspecified: actual contract terms, transaction costs, execution details, and account circumstances. Do not present the quotient as though those fields had been resolved. If the calculation is later compared with an actual record, give the observation its own date and source. Preserve the original assumptions instead of silently changing them to match the later entry. Keep the regulator's limitation attached to the discussion of intended amounts. Do not reduce it to a small-print note while describing the arithmetic as a loss cap elsewhere on the page. Trading involves the risk of loss. ## How do you preserve assumptions? ## Summary Preserve the calculation as a dated version with its inputs, units, source references, and unresolved questions. If a value changes, record a new version and identify the changed field. Keep the earlier arithmetic intact so the reason for the difference remains visible. Write a short assumption note beside each supplied input. For the fictional card, the note can say “chosen for arithmetic illustration.” For a sourced value, retain the source and observation time. Keep rounding decisions separate from the unrounded quotient. This example happens to divide evenly; it does not establish a rounding policy for a different calculation. Use a question field for missing information. “The tick-value source is absent” is a specific record problem. A broad statement that the calculation looks reasonable does not resolve it. Store the original card with the revised versions so the sequence of changes can be followed during review. ## What belongs in the later review? ## Summary Review the equation from its input units through its multiplication and division, then read the unresolved questions separately. Keep the arithmetic result distinct from any real trading decision or outcome. A later review should be able to identify exactly which assumptions produced the recorded quotient. Place the recording procedure in [your written trading plan](/blog/why-a-trading-plan-matters-more-than-a-prediction). Name where source documents, calculation cards, and version notes are retained. For the fictional example, trace the budget of `100` and per-unit amount of `10` into the quotient of `10`. Keep the absence of a real contract and execution record visible. [Our educational approach](/about) gives the wider context for learning calculations while retaining responsibility for decisions. The immediate task here is to understand the equation and its limits. ## Key takeaways - Label the budget, distance, unit value, and quotient separately. - Preserve units and sources at every arithmetic step. - Keep an intended budget separate from an actual loss. - Record missing assumptions and revisions explicitly. ## Disclosure ## Next step Continue learning to read trading calculations with their assumptions visible. [See what we offer →](/what-we-offer) ## Frequently asked questions ### What does ten represent in the fictional result? It is the arithmetic quotient of the supplied budget and per-unit amount. ### Does the example choose a real contract or order? No. Those details are not supplied. ### What belongs beside the equation? Input units, source references, assumptions, and unresolved questions. ## Risk disclosure This article is educational content from One Purpose Trading. It is not financial, investment, tax, or legal advice, and nothing here is a recommendation to buy or sell any security or instrument. Trading involves substantial risk of loss and is not suitable for everyone. You can lose more than your initial investment. Any examples, figures, or scenarios are illustrative only. Results are not typical, and past performance does not guarantee future results. You are responsible for your own decisions. Trade only with capital you can afford to lose, and consider consulting a licensed professional about your individual situation.