Use this UK child maintenance calculator to estimate weekly, monthly, and annual payments using the CMS 2026 guide rates requested for this page. You can enter gross weekly income, number of children, benefit status, and shared care nights to model likely outcomes quickly. The guide below explains each rate band in plain English, includes worked examples, and compares CMS with family-based arrangements so you can decide the most practical route for your situation.
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This tool applies the exact 2026 rate logic specified on this page: nil rate, flat rate, reduced sliding scale, basic percentages, and shared care reductions. Enter your values below, then click Calculate Payment.
Enter your details and calculate to see your estimated child maintenance amount using the CMS 2026 guide method shown below.
Important: This is an independent estimator for planning. It is not a legal determination and does not replace an official CMS decision.
The calculator and guide implement the exact rate statements requested for this page. If you are trying to budget, this is usually enough to model realistic payment ranges before formal contact with CMS. If you are in a dispute, always keep written records and confirm figures through official channels.
| Rate Band | Income Range / Trigger | How This Page Calculates It |
|---|---|---|
| Nil rate | Income under £7/week or receiving qualifying benefits | Payment = £0/week |
| Flat rate | Income £100 to £100.99/week | Payment = £7/week |
| Reduced rate | Income £100 to £199.99/week | Sliding scale estimate from £7 at £100 toward the basic-rate value by £200 |
| Basic rate | Applied using gross weekly income above £100 | 1 child = 12%, 2 children = 16%, 3+ children = 19% of amount above £100 |
The reduced band can be confusing because it is deliberately transitional. In practice, it bridges the jump between a fixed low payment and a percentage-based payment. This guide uses a transparent linear estimator so you can see each step and understand why the amount changes as weekly income increases through the £100 to £199.99 range.
| Shared Care Nights Per Year | Reduction Applied | Multiplier Used In Calculator |
|---|---|---|
| 1 to 3 nights | 0% reduction | 100% of calculated amount |
| 52 to 103 nights | 1/7 reduction | 6/7 of calculated amount |
| 104 to 155 nights | 2/7 reduction | 5/7 of calculated amount |
| 156 to 174 nights | 3/7 reduction | 4/7 of calculated amount |
| 175+ nights | Half rate | 50% of calculated amount |
Key point: shared care is applied after the initial rate amount is calculated. First identify nil, flat, reduced, or basic treatment. Then apply the nights reduction.
Most parents first ask a simple question: “How much will I actually pay or receive each week?” The practical answer is that CMS style calculations are income-led, child-count sensitive, and adjusted by overnight care. This is why two households with similar salaries can still end up with different outcomes if shared care patterns differ or if one parent is on qualifying benefits. The calculator on this page is designed to make those moving parts visible rather than hiding them behind a single number.
Start with gross weekly income. In this guide, income below £7 per week or qualifying benefits immediately triggers nil rate. If income is £100 to £100.99, flat rate of £7 per week applies. The reduced rate then operates across £100 to £199.99 as a sliding amount. Once income is high enough for the basic formula, the calculation uses only the portion above £100 and applies child-count percentages: 12% for one child, 16% for two, and 19% for three or more. This “income above threshold” approach prevents sudden shocks around the first £100 and keeps the method easy to audit.
After that, shared care is applied. If there are 1 to 3 nights per year, no reduction is applied. At 52 to 103 nights, the payer receives a one-seventh reduction. At 104 to 155 nights, it becomes two-sevenths. At 156 to 174 nights, three-sevenths. At 175 nights or more, the amount is reduced to half rate. This matters because care patterns can change over a school year. If nights move into a new band, maintenance can also shift, so keeping an accurate overnight log is essential.
Many disputes happen not because the percentages are unclear, but because parents rely on memory for nights, round income differently, or fail to update arrangements when work changes. If you want fewer arguments and fewer surprises, keep documentation simple and frequent: store weekly income evidence, track overnight stays monthly, and revisit calculations whenever circumstances materially change. A transparent calculation history is often the fastest way to maintain cooperation and avoid escalation.
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The reduced band exists to bridge low and standard liability levels. A fixed payment can feel manageable at low earnings, while a percentage model is more proportional at higher earnings. If the formula switched instantly from flat to full percentage, the jump could be too steep at the threshold, so a sliding method is used. For this page, we calculate that slide in a straight line from £7 at £100 to the equivalent basic-rate outcome at £200. That approach keeps budgeting straightforward and avoids black-box calculations.
Example: assume two qualifying children and income of £150. The basic percentage for two children is 16%. At £200, the basic-rate value on the “above £100” portion would be 16% of £100 = £16. The reduced-band estimate therefore moves gradually between £7 and £16 as income rises from £100 to £199.99. At £150, you are roughly halfway through that interval, so the estimated reduced amount before shared care is roughly halfway between £7 and £16. Then any shared care reduction applies.
This method is intentionally transparent. You can replicate it with a calculator and confirm each step yourself. Transparency matters in family finance, because confidence in the process often reduces conflict more effectively than arguing about a final number. If both parents can see the same formula and the same inputs, discussions usually become practical rather than emotional.
Note on planning: if your income is close to a band edge, small changes in overtime, commission, or working hours can shift the weekly result. Use a buffer in your budget, not just the exact number shown today.
Parents generally choose between a private family-based arrangement and the CMS route. A family-based arrangement can be faster to start, often costs less to administer, and can be tailored around school terms, travel costs, and practical realities that a formula may not capture. It can work very well where communication is stable and both parents are consistent. The weakness is enforceability: if payments become irregular, rebuilding trust can be difficult and arrears can grow before either parent acts.
CMS offers structure. It sets out a defined method, keeps records, and provides a route to enforcement when payments break down. For households where communication is low, conflict is high, or financial reliability is uncertain, formal process can reduce uncertainty. The trade-off is reduced flexibility. Some parents find that a strict formula does not reflect specific household costs, and case administration can feel procedural compared with direct agreement.
In practical terms, the best route depends on reliability and documentation. If both households can agree quickly, maintain records, and adapt calmly when income changes, a family-based arrangement can be effective. If there is repeated non-payment, unresolved disagreement on nights, or frequent income disputes, CMS structure may become necessary. Neither option is automatically better in every case; fit depends on behavior over time.
| Area | Family-Based Arrangement | CMS Route |
|---|---|---|
| Flexibility | High flexibility on amounts, schedules, and practical extras | Lower flexibility; formula-led approach |
| Speed to start | Can start immediately if both agree | Formal process and administration steps |
| Enforcement | Limited without legal escalation | Formal enforcement pathways available |
| Transparency | Depends on quality of shared records | Structured calculation and case records |
| Suitability | Best where trust and communication are strong | Best where reliability or agreement is weak |
The application fee in this guide is £20. For many households this is the first practical consideration, but it should not be the only one. The larger question is whether the arrangement will stay reliable over time. A low upfront cost is less valuable if payments then become irregular and require repeated chasing. For that reason, many parents first run a clear estimate, discuss expectations, and document agreed assumptions before selecting a route.
Good setup practice is simple. First, agree what income evidence will be used and how often it will be refreshed. Second, agree how shared care nights will be logged and what counts as an overnight stay. Third, set review points in advance, for example every six or twelve months, or whenever income changes materially. Fourth, record any additional child-related costs separately from base maintenance so that one-off expenses do not distort the core calculation.
If an agreement starts privately, keep a written summary signed by both parents and date each revision. If discussions break down later, that history can help clarify what was previously accepted. If you proceed through CMS, keep copies of submissions, notices, and payment records in one file. In either route, consistent record-keeping is usually the difference between smooth adjustments and repeated disputes.
When circumstances shift, act early. Waiting months to address changed income or care patterns often creates larger corrections and harder conversations. A practical approach is to run this calculator whenever there is a new work pattern, major overtime shift, or sustained change in care nights. Treat the estimate as a budgeting baseline, then confirm through the formal process when needed.
Example 1: Flat rate scenario. Gross weekly income is £100.50, one qualifying child, and 10 shared care nights. This falls in the page’s flat-rate band (£100 to £100.99), so the amount is £7 per week before shared care. Shared care at 10 nights is below the reduction thresholds, so no discount applies. Final estimate is £7 weekly, around £30.33 monthly, and £364 annually.
Example 2: Reduced rate with shared care deduction. Gross weekly income is £160, two children, and 80 shared care nights. Two-child basic percentage is 16%. Basic-rate reference value at £200 is 16% of £100 = £16. Reduced estimate at £160 is partway between £7 and £16. Then shared care of 80 nights gives a 1/7 reduction, so the final weekly amount is multiplied by 6/7. This produces a lower total than the pre-reduction estimate and shows how nights can materially affect budgeting.
Example 3: Basic rate with two-sevenths reduction. Gross weekly income is £450, one child, and 120 shared care nights. Basic formula uses income above £100: £450 - £100 = £350. One-child percentage is 12%, so base amount is £42 weekly. Shared care at 120 nights gives a 2/7 reduction, so final amount is 5/7 of £42, or £30 weekly. This illustrates why both income and care data are necessary; income alone would overstate liability.
Example 4: Three-plus children with half-rate shared care. Gross weekly income is £700, three or more children, and 182 shared care nights. Income above threshold is £600. Percentage is 19%, giving £114 before shared care. Because nights are 175+, half rate applies, so final estimate is £57 weekly. This is a large adjustment and demonstrates why accurate annual night totals are critical in high-care shared arrangements.
Example 5: Nil-rate due to qualifying benefits. Gross weekly income may vary, but qualifying benefits are in payment. Under the rule set for this page, nil rate applies and estimated maintenance is £0 weekly. If benefit status ends or income structure changes, re-run the calculation immediately so both households can plan around updated expectations.
Use the same definitions each time. Agree what counts as gross weekly income and what documents prove it. Agree what counts as an overnight stay. Keep one shared record with dates and totals so nobody has to reconstruct a year from memory. Review the amount when there is a clear, sustained change rather than reacting to one unusual week.
When discussions become tense, return to process: same inputs, same formula, same review date. This prevents conversations from turning into personal disputes and keeps focus on child-related stability. If direct agreement is no longer workable, moving to a formal pathway early is usually better than allowing arrears and frustration to build.
Budget conservatively. Maintenance values can change with earnings, hours, and care patterns. A cautious household budget includes a buffer rather than relying on one precise point estimate. That approach protects both households and supports consistent spending for children across the year.
No. It is an independent UK calculator that applies the 2026 guide rates and shared care rules shown on this page. It helps with planning, budgeting, and understanding formula mechanics. Official liability can only be confirmed through the formal CMS process and case-specific evidence. Use this estimator as a practical starting point, then verify formally if you need a binding figure.
The reduced band is transitional between a fixed amount and a percentage model. To keep the method transparent, this page estimates the band by moving from £7 at £100 income toward the basic-rate value at £200. That creates a smooth curve in everyday budgeting and avoids abrupt jumps. It is intentionally easy to audit, but you should still confirm final liability through official channels when required.
This page uses 12% for one child, 16% for two children, and 19% for three or more children. These percentages are applied to gross weekly income above £100 in the basic band. After that, shared care reductions are applied based on annual overnight stays. Always check both inputs together, because changing either one can move the final weekly payment meaningfully.
Shared care deductions are banded by annual nights. 1 to 3 nights gives no reduction. 52 to 103 nights gives a 1/7 reduction, 104 to 155 gives 2/7, 156 to 174 gives 3/7, and 175+ gives half rate. The reduction is applied after the initial rate calculation. Keep a dated overnight record, because evidence quality often determines whether a deduction is accepted without dispute.
The guide value on this page is a £20 application fee to open a CMS case. Some applicants may be exempt depending on circumstances, so eligibility should be checked before applying. In practical budgeting, treat the fee as setup cost and focus primarily on long-term payment reliability. A predictable arrangement usually matters more than the one-time entry fee.
If both parents communicate well, keep records, and pay reliably, a family-based arrangement can be efficient and flexible. If communication is difficult or payments are inconsistent, CMS structure may reduce uncertainty through defined processes and enforceability. The best choice depends less on preference and more on whether your current arrangement performs consistently over time without repeated disputes.
Review when income changes materially, when shared care nights shift into a new band, or when family circumstances change. Even if life appears stable, an annual review is sensible. Regular recalculation helps avoid sudden corrections, keeps both households informed, and supports steady child-focused planning. Consistency in review timing is often as important as the formula itself.