Best Endeavours Meaning: Best vs Reasonable Endeavours Clauses Explained

If you run a small business, you’ve probably seen “best endeavours” tucked into contracts with customers, suppliers, landlords, or collaborators.

It can look harmless - even reassuring - but a best endeavours clause can shift real risk onto you if something gets difficult, expensive, or time-consuming.

This guide breaks down what “best endeavours” generally means in a UK commercial context, how it compares to “reasonable endeavours”, and how to use these clauses in a way that protects your business (without scaring off the other side).

This article is general information for UK businesses and isn’t legal advice. Endeavours obligations are fact-specific, so get advice on the wording in your contract.

What Does “Best Endeavours” Mean In UK Contracts?

In plain English, a best endeavours obligation usually means:

• You must take all steps you reasonably can to achieve a particular outcome; and
• You can’t just do the easy or cheap steps and stop when it becomes inconvenient.

It’s important to spot the difference between:

• An obligation to do something (for example, “You must deliver by Friday”), and
• An obligation to try to achieve something (for example, “You must use best endeavours to obtain planning approval”).

“Endeavours” language is usually used where the result isn’t entirely within your control. For example, you might need a third party to approve something, a regulator to issue a licence, or a supplier to deliver a component on time.

Even though it’s not a guarantee of success, a best endeavours obligation is still a serious legal commitment. If you don’t do enough to try, you may be in breach of contract - even if the outcome was never achievable.

Because endeavours clauses are a form of contractual promise, they sit within the wider rules around what makes a contract enforceable. If you’re unsure how these promises become binding in the first place, it helps to understand the basics of Contract formation.

What Does “Best” Actually Require?

UK contracts don’t come with a universal checklist for “best endeavours”. Instead, what’s required depends on:

• the wording of the clause (and the contract as a whole)
• what the parties knew at the time they signed
• industry norms (what a sensible business in your position would do)
• the cost, time, and practicality of possible steps
• whether the steps would seriously harm your business

A common trap for small businesses is assuming “best endeavours” just means “try hard, within reason.” In practice, it can mean you need to take multiple steps, pursue alternatives, and keep going for longer than you’d like - especially where there are obvious further actions available.

Reasonable Endeavours Vs Best Endeavours: What’s The Difference?

Many business owners search for “reasonable endeavours vs best endeavours” because these phrases sound similar - but they can place very different levels of pressure on you.

Here’s a practical way to think about the spectrum (from weakest to strongest) - noting that the exact standard can vary depending on the contract wording and context:

• “Reasonable endeavours” - take reasonable steps, but you may be able to stop once further steps become disproportionate, too costly, or unlikely to succeed.
• “All reasonable endeavours” - often treated as stronger than “reasonable endeavours”; you may need to take a broader range of reasonable steps (possibly trying multiple routes), but not necessarily every step imaginable.
• “Best endeavours” - typically the strongest; you may need to take all steps a prudent and determined business would take to achieve the result, even if that involves some extra cost or effort (short of seriously jeopardising the business).

A Simple Small Business Example

Let’s say you’re a growing ecommerce business, and your supplier contract says you must use “best endeavours” to source substitute stock if their shipment is delayed.

That could push you to:

• contact multiple alternative wholesalers, not just one
• accept a higher unit price (within reason)
• pay for expedited shipping
• adjust your production schedule
• prove you followed up consistently and kept proper records

Under “reasonable endeavours”, you might reasonably decide the extra cost is too high, or the chance of success is too low - and stop earlier.

So when people compare best endeavours v reasonable endeavours, what they’re really comparing is how far you must go before you’re allowed to stop.

Where Does “Commercially Reasonable Efforts” Fit In?

Sometimes you’ll see “commercially reasonable endeavours/efforts” (often in contracts influenced by US drafting).

The idea is usually: take steps that are reasonable in a commercial sense - meaning you don’t have to destroy your profit margin or business stability to achieve the outcome.

If this wording is being proposed, it’s worth aligning it with the rest of your agreement so you don’t end up with vague obligations that are hard to manage. This broader concept is often discussed in the context of Commercially reasonable efforts.

When Do Best Endeavours Clauses Usually Appear (And Why)?

You’re most likely to see a best endeavours clause where a contract outcome depends on factors outside one party’s direct control.

Common scenarios include:

• Approvals and licences (planning permission, industry accreditations, regulatory consents)
• Third-party cooperation (landlords consenting to fit-out works, suppliers providing materials, platforms approving integrations)
• Time-sensitive milestones (launch dates, completion dates, “go-live” deadlines where delays can happen)
• Fundraising or investment steps (e.g. a founder must use best endeavours to secure a key hire or sign a strategic deal)
• Dispute resolution obligations (using best endeavours to settle or mitigate losses)

From a practical perspective, the other side often wants “best endeavours” because it feels safer: it reduces the risk that you’ll do the bare minimum and walk away.

But as a small business, you need to be careful - your cashflow, staffing, and supplier leverage might not support a heavy “best endeavours” obligation.

Why Best Endeavours Clauses Can Be Risky For Small Businesses

Best endeavours clauses become risky when they’re vague and connected to outcomes that are costly or hard to evidence.

Here are the key issues we regularly see for SMEs:

1) You Might Be Expected To Spend Money You Didn’t Budget For

A best endeavours obligation can effectively force you to absorb extra costs (for example, paying overtime, hiring contractors, using premium suppliers, or fast-tracking deliveries) if that’s what it takes to try to hit the target.

This doesn’t always mean “spend unlimited money”, but it can still mean spending more than you’re comfortable with - especially if the contract doesn’t set boundaries.

2) It Can Create Arguments About “What You Should Have Done”

If the outcome isn’t achieved, the dispute often becomes: did you do enough?

That can lead to time-consuming back-and-forth about:

• which alternatives you considered
• how quickly you acted
• how often you followed up
• whether you should have escalated internally
• whether you should have tried a different supplier/approach

In other words, it’s not always the failure that triggers liability - it’s the failure to evidence effort.

3) It Can Clash With Your Other Contract Promises

Sometimes businesses accept a best endeavours obligation without checking whether it conflicts with:

• delivery timeframes elsewhere in the contract
• service levels and performance metrics
• your staffing capacity (especially if you’re a lean team)
• your duty to comply with law and safety obligations

If you’re signing multiple documents (like order forms plus terms and conditions), you’ll want the endeavours language to be consistent across the whole deal, including your Terms and conditions.

4) It Can Increase Your Damages Exposure

If the other party claims you didn’t use best endeavours and they suffered loss, they may seek damages. The scale of those damages depends on the contract and what losses were foreseeable.

This is one reason endeavours clauses should be reviewed alongside your risk allocation provisions, including Limitation of liability wording.

How To Draft (Or Negotiate) Endeavours Clauses So They’re Clear And Fair

The goal with endeavours clauses isn’t to avoid responsibility - it’s to make sure you’re agreeing to something you can realistically manage, measure, and prove.

Here are practical ways to do that.

1) Define The Outcome Clearly

Instead of vague obligations like:

• “The Supplier must use best endeavours to deliver the Services promptly.”

Try to tie it to something more concrete:

• a milestone date (“use best endeavours to deliver by 30 June 2026”)
• a particular approval (“use best endeavours to obtain Landlord consent”)
• a specific process (“use best endeavours to submit the application within 5 business days”)

The clearer the target, the easier it is to manage expectations (and reduce disputes later).

2) List What Steps Are Required (Or Not Required)

This is one of the most business-friendly ways to reduce ambiguity.

You can spell out what “endeavours” includes, such as:

• making a set number of follow-up attempts
• contacting named alternative suppliers
• escalating internally to a director
• providing weekly progress updates

And you can also clarify what it doesn’t require, such as:

• starting legal proceedings against a third party
• incurring costs above an agreed cap
• agreeing to terms that are materially adverse
• disclosing confidential information beyond what is necessary

This kind of drafting turns a fuzzy “try your best” promise into a practical action plan.

3) Add A Cost Or Resource Cap (Where Appropriate)

Especially for small businesses, it’s reasonable to set boundaries. For example:

• “…provided that the party is not required to incur costs exceeding £X”
• “...provided that the party is not required to materially disrupt its business operations”

Whether the other party will accept this depends on leverage and context, but it’s often better to negotiate a cap than to sign an open-ended obligation you can’t realistically meet.

4) Link Endeavours To Timeframes And Information Duties

If a clause says you must use best endeavours “as soon as possible”, you can end up arguing about what “soon” means.

To avoid that, consider:

• clear response times (e.g. within 2 business days)
• reporting requirements (e.g. progress updates every week)
• clear triggers (e.g. “if X happens, you must do Y”)

This is particularly useful where delays can cause knock-on effects in your supply chain or project plan.

5) Make Sure The Contract Is Properly Executed

Even the best-drafted endeavours clause won’t help if the contract signing process is messy.

For example, questions about who signed, whether the right entity signed, or whether the agreement was properly executed can become a problem if there’s a dispute later. If your deal needs to be signed as a deed (or you’re not sure), it’s worth getting comfortable with Executing deeds and contracts.

How Do You Prove You Used Best (Or Reasonable) Endeavours?

If you ever have to defend your efforts, you’ll want evidence that you acted proactively, consistently, and sensibly.

That means building simple habits into your operations - nothing fancy, just enough to show what happened.

What Evidence Helps Most?

• Email trails showing follow-ups, escalations, and attempted solutions
• Call notes (date, time, who you spoke to, what was agreed)
• Alternative quotes from substitute suppliers or providers
• Internal task tracking (even a simple project board or checklist can help)
• Progress updates sent to the other party (so they can’t say you went quiet)

Be careful not to assume “it’s fine because we spoke on the phone.” When there’s a disagreement later, it’s far easier to prove effort with written records. This is one reason businesses still rely heavily on email, and why questions like Email agreements matter in day-to-day contract management.

What If The Other Side Refuses To Cooperate?

Sometimes, you can do everything right and still face an unresponsive third party (for example, a landlord who won’t reply, a platform that won’t approve, or a customer who won’t provide information).

If you have an endeavours obligation in that situation, your focus should be on:

• following up at reasonable intervals
• offering practical alternatives
• clearly communicating what you need from them
• documenting silence or refusal

In many cases, the best protection is having the contract say what happens when third parties don’t cooperate (for example, extension of time, suspension rights, or a termination right).

Key Takeaways

• In UK business contracts, “best endeavours” generally means taking all reasonable steps to achieve the stated outcome, not just the easiest or cheapest steps (but what’s required depends on the wording and context).
• When comparing reasonable endeavours vs best endeavours, the practical difference is often how far you must go before you’re allowed to stop - with best endeavours usually the stronger obligation.
• Endeavours clauses are common where outcomes rely on third parties (like approvals, consents, or supply chain dependencies), but they can be risky if they’re vague.
• You can reduce risk by defining the target outcome, listing required steps, setting cost/resource limits, and adding timeframes and reporting obligations.
• If there’s ever a dispute, evidence matters - keep written records (emails, follow-up notes, alternative quotes) to prove the efforts you made.
• Endeavours obligations should be reviewed alongside the rest of your contract, including your key commercial terms and your limitation of liability position.

If you’d like help reviewing or drafting a contract with a best endeavours clause (or negotiating it so it’s workable for your business), you can reach us at 08081347754 or team@sprintlaw.co.uk for a free, no-obligations chat.