Mortar Mix Calculator

Mortar holds masonry together, but it does far more than that: it cushions differential movement, sheds water, and patiently lets old buildings breathe. Different structures need different strengths, and a mortar that is too hard is not a small mistake — it cracks the very bricks it is meant to protect. That is why the mix is not just "cement and sand", but a carefully proportioned blend of cement, lime, sand and water chosen for the job.

Mortar Mix Calculator estimates the cement, lime, sand and water for masonry mortar by wall area, wall volume or repointing area, across the four standard mortar types (M, S, N, O) plus custom ratios in both imperial and metric units. It returns bags of cement, lime and sand by volume and weight, and even approximates ready-mix bags and brick counts so the estimate matches what you actually buy.

The learning guide explains what each mortar type is for, why lime is the friend of old masonry, and how to read a hand-mixed ratio. Everything runs in the browser — nothing is uploaded.

• By area or volume: Enter wall dimensions and thickness, or jump straight to a known mortar volume.
• All standard types: Type M, S, N and O with their true proportions, plus a custom cement : lime : sand ratio.
• Brick-count estimate: Approximate number of standard bricks or blocks a batch covers based on your joint settings.
• Ready-mix conversion: Switch to prepackaged mortar and see the number of 25 or 40 kg bags instead of components.
• Full material bill: Cement bags, lime bags, sand by volume and weight, and water in litres — everything the mix needs.
• Imperial or metric: Feet, inches and meters mix freely, with volumes in cubic feet, cubic yards and cubic metres.
• Waste adjustment: A 5–10 percent waste default for site losses and dropped batches.
• Live estimate: Material quantities update as you type, with the dry-volume factor shown at every step.
• Export: Copy or download the full mortar report as text, CSV or JSON.
• Learning guide: Type-uses table, ratio explainer, repointing notes and masonry best practice built in.

1. Pick the input mode. Wall measurements for new masonry, or direct volume/area for repointing and repairs.
2. Enter wall length, height and thickness. The mortar volume is derived from the wall volume using your mortar-percent setting.
3. Choose the mortar type. Type N for general above-grade walls, Type S for load-bearing and below-grade, Type O for repointing historic masonry, Type M for heavy concrete foundations.
4. Set the ratio if you choose custom. Enter cement, lime and sand parts directly — the proportions shown do the rest.
5. Pick ready-mix or site batch. For acknowledged bag mixes choose ready-mix; otherwise the tool splits components.
6. Set the waste allowance. 7 percent is a healthy default for a tidy site.
7. Read the estimate. Cement, lime, sand and water appear instantly, with brick counts beneath.
8. Review the working. The maths line shows volume × mortar-percent × dry factor / parts so every number is traceable.
9. Export the report. Copy or download as text, CSV or JSON for the supplier.
10. Check the guide. The learning tab covers type selection and lime safety.

Example 1 — House wall. A 30×8×0.66 ft wall (30×8×8-in) with 25% mortar = 39.6 cu ft of dry mortar. Type N 1:1:6 gives about 1.4 bags of cement, 100 lb of lime and 0.9 cu yd of sand.

Example 2 — Retaining wall. A 4-inch, 20×6 ft wall in Type S (1:0.5:4): ~4 cu ft of mortar ≈ 0.9 bags of cement, 45 lb lime and 0.2 m³ sand, strong enough for lateral soil pressure.

Example 3 — Repointing a chimney. Repointing 400 sq ft of brick at 3/8-inch joint needs roughly 1.3 cu ft of lime-rich Type O per 100 sq ft — about 5 cu ft total for the chimney, batched in small lime putty mixes.

Example 4 — Block wall metric. A 6 m × 2.5 m × 0.2 m block wall with 25% mortar = 0.75 m³ dry mortar; on 1:1:6 that is ~2.2 bags of 50 kg cement, ~55 kg lime and ~0.6 m³ sand.

Example 5 — Checking a quote. A contractor orders 30 bags of "mortar mix" for a garage wall. The calculator at 1:1:6 says 28 bags of components equivalent — the quote is right, and now you know why.

• Right mortar for the wall: Type guidance keeps old brick and new block both in the mix they need, not just the strongest one on the shelf.
• Order components or bags: Batched cement/lime/sand or ready-mix bags — the bill matches how you buy.
• Know the ratio: Custom ratios make clear where strength comes from and avoid accidentally strong or weak mixes.
• Brick-count sanity check: See how much masonry a batch covers before investing in a full wall order.
• Explainable maths: Volume → mortar-percent → dry factor → parts, with every step visible.
• Export-ready: Text, CSV and JSON reports drop into purchase orders and quotes.
• Free and private: No uploads, no accounts, no logging.